A powerful earthquake struck southwestern Japan Tuesday afternoon local time, collapsing part of a shopping mall, toppling a stone wall at the centuries-old Kumamoto Castle, and sending more than 150,000 people to evacuation shelters, the BBC reported.

The quake, which the U.S. Geological Survey (USGS) measured as a magnitude 6.8, hit at 4:27 p.m. local time near Kumamoto, a city of more than 700,000 people located on the island of Kyushu in southern Japan.

Thousands of homes lost power, and roads buckled across the region. The second floor of a shopping center collapsed, trapping shoppers inside, according to the BBC report; some of these people were evacuated and later hospitalized. A brief tsunami warning was issued and lifted within an hour.

The USGS measurement is different from the magnitude 7.1 reported by the Japan Meteorological Agency, "primarily because the agencies are reporting different magnitude types," the USGS reported. While Japan is looking at local magnitude, the USGS measured the moment magnitude, which is derived from the physical size of the fault rupture and gives the "most reliable estimate of earthquake size" for large earthquakes, since local-magnitude scales can lose accuracy once a rupture grows big enough, the USGS reported.

These measurements are helpful, as "different magnitude types capture different characteristics of earthquake source processes," the USGS noted. Local magnitude, for example, reflects how strongly the ground shook nearby, while moment magnitude reflects the total energy released across the fault.

Why this quake is scientifically interesting

Japan sits atop one of the most active plate boundaries on Earth, where the Philippine Sea Plate dives beneath the Eurasia Plate. That process, known as subduction, is responsible for the massive, tsunami-generating earthquakes that periodically strike offshore Japan, and it's been studied intensively for decades.

But Tuesday's earthquake didn't occur at the boundary itself. Instead, the rupture happened within the Eurasia Plate, more than 60 miles (100 kilometers) inland from where the plates meet, Jeffrey Park, a theoretical seismologist at Yale University, told Live Science. Roughly 90% of earthquakes happen at plate boundaries, where the constant grinding of two plates builds up stress until a fault gives way. Quakes that strike farther inside a plate — sometimes called intraplate earthquakes — are rarer and less understood, though scientists suspect that stress transmitted through the plate can reactivate old, dormant faults far from the boundary that produced it.

According to Park, the fault in Tuesday's earthquake moved in a way that suggests the plate tore horizontally as it was twisted by subduction occurring at an angle.

The USGS describes this event as shallow strike-slip faulting: the two sides of the fracture slid past each other horizontally, rather than one side thrusting up and over the other. This faulting style, combined with the shallow depth of just 6 miles (10 kilometers) down, points to the same type of rupture behind Kyushu’s deadly 2016 Kumamoto earthquake sequence.

That inland location is also why the quake didn't generate a damaging tsunami, despite the brief precautionary warning. Tsunamis are produced when a big event ‪—‬ such as an earthquake, volcanic eruption or landslide ‪—‬ displaces water; the force from that displacement then propagates as a wave.

Tuesday's rupture stayed entirely on land, so it never pushed the seafloor up the way offshore quakes do. That's why the tsunami risk stayed low, even with the brief precautionary warning. Still, an inland quake isn't automatically off the hook: if the shaking triggers a landslide that spills into the sea, that alone can generate a tsunami.

The depth mattered just as much as the location. The quake was shallow enough to concentrate its energy near the surface, which Park said explains the structural damage.

"Because it is shallow it will cause more structural damage than a similar-sized event that might occur deeper and offshore," he told Live Science in an email.

Earthquake country

Several earthquakes have already clustered in the area, and numerous aftershocks are expected over the coming days. Japan experiences roughly 1,500 earthquakes annually, making it one of the most seismically active countries on the planet — a byproduct of sitting at the junction of several tectonic plates.

To protect itself, Japan has spent decades — and learned from painful lessons from disasters like the 2011 Tohoku earthquake and tsunami — engineering a response system built for exactly this scenario.

Bullet trains are programmed to halt automatically the instant seismic sensors detect a major earthquake, a safeguard Park pointed to as a defining feature of the country's earthquake readiness. That automatic shutdown extends to other transit and utility systems, part of a broader early-warning network that alerts the public within seconds of a quake's detection, giving people crucial time to take cover before shaking arrives.

Japan's investment in its infrastructure may help to explain why, even after a magnitude 7 event near a city of 700,000, Japan's death toll and damage have historically been far lower than those from comparable quakes elsewhere in the world.

Search-and-rescue efforts are continuing in Kumamoto, with CNN reporting that between 20 and 30 employees remained unaccounted for at the Aeon Mall in Kashima Town, where the building’s second floor had collapsed. Firefighters were also working to reach the site and contain nearby fires.

About a decade ago, the Japanese government spotted a worrying pattern: Pediatricians were doling out a ton of antibiotics, well beyond what should be needed to treat the bacterial infections coming through their doors.

Antibiotics treat bacterial infections, not those caused by viruses, fungi or parasites. Yet doctors were often sending young patients home with antibiotics for illnesses unlikely to be bacterial. Treating nonbacterial infections with antibiotics can fuel antimicrobial resistance (AMR) and the rise of superbugs by unnecessarily exposing bacteria to the drugs, pressuring those bacteria to evolve strategies to survive. Resistant bacteria can then spread their adaptations to others, thereby compounding the problem.

In the long run, resistance could make common infections impossible to treat with existing drugs, raising the risk of serious illness and death across the population.

When pediatricians in Japan did treat bacterial infections, they were overusing the antibiotics that are likely to fuel resistance — "broad-spectrum" drugs that target many bacteria at once. When compared against 35 other high-income countries in 2015, Japan ranked dead last in the appropriateness of antibiotic choices for kids under 5.

One way to slow the development of AMR is to get antibiotic prescriptions under control. So Japan focused on one of its biggest sources of problematic antibiotic use: pediatric outpatient clinics.

"The clinics are a particular problem," said Dr. Yusuke Okubo, chief of clinical epidemiology and health services research at the National Center for Child Health and Development, a research center and hospital in Tokyo. Looking at Japan's overall antibiotic use, "90% of prescriptions are [from] outpatient clinics, not hospitals," Okubo told me. (Outpatient practices account for a similar proportion of antibiotic prescriptions in the U.S.)

A large proportion of problematic prescriptions were being written for children under 3 years old, especially those with upper respiratory tract infections, which nine times out of 10 are caused by viruses, Okubo said. The stomach bug gastroenteritis was another biggie for overprescription, despite most often being caused by a virus.

Government officials hatched an idea: What if each time a pediatrician chose not to prescribe an antibiotic in these cases, they earned a small financial reward — a tip for making a better choice? Each tip would be small, amounting to about $5 per claim at today's exchange rate, but could translate to thousands of extra dollars of annual income for individual clinics. That's no small matter for Japanese pediatricians, who Okubo estimates earn roughly $90,000 to $100,000 a year.

This incentive program, rolled out in 2018, has proved a success, so much so that it's since been expanded to cover more patients, more clinics and a wider variety of diseases. But what made the program work? I went to Japan to find out what systemic and cultural factors contributed to the program's success. Ultimately, I wanted to see whether other countries, like the U.S., could learn from this nationwide experiment.

The quietly rising threat of resistance

With bacteria, as with animals, it's survival of the fittest. When exposed to antibiotics, a percentage of bacteria die, while others survive. That surviving population has traits that help them withstand the drug's effects, which are encoded in "resistance genes." Bacteria can transfer those genes to the next generation by multiplying, as well as physically pass those genes to nearby bacteria. Plus, they can pick up new resistance genes through random DNA mutations.

All antibiotics come with the risk of pressuring bacteria to evolve resistance — it's an inherent feature of the drugs. However, broad-spectrum drugs carry the greatest risk, because they place pressure on a wider variety of bacteria than narrow-spectrum drugs do. The 2015 cross-country comparison found that Japanese doctors prescribed antibiotics with the lowest risk of resistance only 35% of the time, meaning most antibiotic prescriptions were for broader-spectrum drugs.

It's sometimes necessary to use broad-spectrum drugs — such as when an infection is resistant to narrow-spectrum options — but using broad-spectrum antibiotics when they're not needed hastens the development of AMR. So does using antibiotics for nonbacterial infections. In both scenarios, you're introducing evolutionary pressure that could have otherwise been avoided.

Globally, resistance is rising among common disease-causing bacteria; it's far outpacing the development of alternatives to antibiotics. In 2021, resistant bacterial infections directly caused 1.14 million deaths worldwide and contributed to another 3.57 million deaths. Those numbers could climb dramatically by 2050 if swift action isn't taken now.

Common pathogens already show high rates of resistance in Japan, and resistant germs contribute to thousands of deaths each year, with most occurring among older adults. People over 65 make up about 30% of Japan's population. As that percentage grows in the coming years, AMR-related illness may also increase, health officials worry.

Japan's youngest residents are also at risk, though, as resistant bacteria can sometimes pass from mothers to newborns at birth and can cause serious complications, like sepsis. Resistance has also been detected among respiratory bugs that frequently infect kids, such as Mycoplasma pneumoniae, said Dr. Takemi Murai, deputy head of the Infectious Diseases Division at Nagano Children's Hospital in Azumino. "There have been outbreaks of Mycoplasma that are resistant to antibiotics," he said.

Yet not long ago, the unrestrained use of antibiotics was a mainstay of Japanese medicine. (I'll dig into the myriad reasons why in later installments of this series.)

National insurance data sampled from 2005 showed that 60% of patients in Japan with nonbacterial upper respiratory tract infections were prescribed antibiotics, mostly broad-spectrum ones like third-generation cephalosporins, macrolides and quinolones. Most of those prescriptions came from clinics.

Something had to shift.

Tips for appropriate treatment

In 2016, Japan got serious about reducing its antibiotic misuse, releasing its first National Action Plan on Antimicrobial Resistance. It aligned with a global plan from the World Health Organization, which aimed to raise awareness of AMR and optimize the use of antimicrobials, including antibiotics, among its member states.

Two of Japan's big goals were to slash overall antibiotic use by 33% and broad-spectrum antibiotic use by 50% by 2020. The country came very close to hitting those ambitious targets by the deadline, and doing so was no small feat. The tipping program was just one of a slew of initiatives introduced to improve AMR awareness and antibiotic use.

Prior to the incentive's introduction, Japan's Ministry of Health, Labour and Welfare (MHLW) — whose role is somewhat analogous to the U.S. Department of Health and Human Services — rolled out educational campaigns for doctors and patients and wrote a manual for antibiotic use, with the first edition directed primarily at outpatient doctors. It emphasized that most acute respiratory tract infections and acute diarrheal diseases don't require antibiotics.

Among kids, children under 5 saw the highest antibiotic prescription rates, often receiving the drugs for respiratory infections. Data showed this overprescription problem was the worst in children under 3 being assessed for upper respiratory infections or acute gastroenteritis. The government's solution? Pay doctors extra to withhold antibiotics when faced with cases that don't warrant them.

"If the clinicians provide more appropriate medical services, we add additional payment," said Dr. Takuma Kato, a counselor at the Permanent Mission of Japan to the United Nations who previously worked on the incentive program for MHLW. In this case, they pay "a little bit more" when doctors don't give patients antibiotics for illnesses that are likely viral, he said.

A "little bit more" is accurate. Each tip is 800 yen, equivalent to about $7.20 when the program launched in April 2018 and about $5 at today's exchange rate.

Here's how it works: A caregiver brings in their sick infant or toddler for an initial visit, and the pediatrician determines the child likely has an acute upper respiratory tract infection or gastroenteritis. These illnesses are typically caused by viruses, so the doctor decides not to provide an antibiotic. The doctor explains this rationale to the caregiver and provides guidance for home care. If the appointment checks those boxes, the clinic can claim an extra 800 yen when they seek reimbursement.

Because mild viral infections typically resolve on their own in a few days, a strategy called "watchful waiting" can help clarify if a bacterium is actually at fault. So if a doctor does prescribe an antibiotic at the first visit, they'll often encourage the caregiver to bring the child back if their condition remains the same or worsens within a few days. The incentive and this "waiting" strategy go hand in hand.

There are a few technicalities. For example, the children being assessed must have no underlying conditions that might complicate their case, such as a weakened immune system. If children test positive on a formal diagnostic test for influenza or COVID-19, the incentive cannot be claimed. To qualify for the incentive, clinics must specialize in pediatrics and use a "comprehensive" payment system, meaning patients pay a standardized amount for the whole appointment rather than the itemized "fee for service" that is ubiquitous in the U.S.

Despite this fine print, the perk is pretty appealing for the clinics that claim it. "I think pediatric doctor associations are really happy," Okubo said.

Doctors say "small incentives add up"

The Japanese government generally incentivizes doctors to adjust their behaviors, rather than penalizing them for poor practices, Okubo said.

"It's a constructive message from the government: 'You changed your behavior, so we'll pay something,'" Okubo said. "This constructive approach motivates physicians, especially pediatricians, to apply their common sense to their actual practice."

This system is readily accepted by Japanese doctors, who have historically held a lot of political power, Kato noted. Just like in the U.S., their professional groups, such as the Japan Medical Association, lobby the government and typically push against policy proposals that they view as potential threats to their bottom line.

By contrast, an incentivizing approach is "very, very welcome, especially by the doctors' associations," said Dr. Norio Ohmagari, director of disease control and prevention at the National Center for Global Health and Medicine, part of the Japan Institute for Health Security (JIHS) in Tokyo. Ohmagari also leads the AMR Clinical Reference Center, which collaborates with the WHO on AMR countermeasures.

Doctors I asked confirmed that they like the incentive, namely because it boosts their profits.

"I apply for the pediatric antibiotic appropriate use support premium each time" it's applicable, said Dr. Yusuke Shibata, who runs the Shibata Pediatric Clinic in Asakusa, a historic district in Tokyo's Taito ward. "I appreciate the premium, as pediatric clinics already have low profits" compared with clinics that care for adults, Shibata told me in an email after I visited his clinic.

For first visits with kids under 6, clinics are paid a base rate of 6,040 to 7,210 yen, or about $38 to $45 at current exchange rates. An extra 800 yen (about $5) increases that fee by more than 10% — "a huge amount," Okubo emphasized.

Shibata estimates that his clinic sees about 30 to 40 patients with an acute respiratory infection or diarrhea each week, depending on the season. He can potentially claim the incentive for the first visit with each of these patients, assuming they don't have any conditions that would disqualify the claim.

On the high end, Shibata estimates that he might claim the incentive 180 times in a single busy month, which would total 144,000 yen, or about $900.

Dr. Atsushi Miyahara, who runs the Karugamo Clinic in the Setagaya ward in Tokyo, said he was already conservative about using antibiotics so the incentive rewards him for sticking with his status quo.

Fifteen years ago, when Miyahara opened his clinic, he noticed that other physicians prescribed a lot of antibiotics, and he questioned the practice due to the potential to fuel resistance. He provides his patients with informational flyers that explain the risks of resistance and how avoiding unnecessary prescriptions can reduce that risk. When antibiotics are needed, he predominantly uses narrow-spectrum drugs that pose a relatively low risk of resistance.

Miyahara said the local government and medical associations announced the antibiotic incentive when it was launched, and he felt its introduction has been very positive. It's increased his revenue and encouraged him to continue his stewardship practices. He estimates that for every 50 of his first visits with patients, he claims the incentive 10 to 15 times, so it applies to at least 20% of those visits.

The incentive's impact

Because some pediatric clinics qualified and others didn't — due to fee-for-service clinics being excluded — Okubo and his colleagues could directly measure whether the policy worked.

To assess the incentive's effects in its first year, the researchers looked at insurance claims from over 10,000 medical facilities from just before and after the policy's introduction. About 3,000 of the facilities qualified and claimed the incentive 316,770 times, totaling 253 million yen ($2.29 million at the time). These eligible clinics saw a 17.8% reduction in their total antibiotic use over a year without any negative effects for patients, such as higher hospitalization rates.

To see if those effects lasted, the team drew years of data from over 165,000 young children who went to either eligible or ineligible clinics. Within the first month of the policy's implementation, the former group of children saw a nearly 45% reduction in total antibiotic prescriptions, compared with the other kids. Cumulatively over the next four years, their overall antibiotic use and broad-spectrum-antibiotic use was 20% and 24% lower, respectively.

The decrease in antibiotic prescriptions did not come with an uptick in hospitalizations or healthcare costs, although there was a slight increase in the total number of doctor's visits. But that's what you'd expect as doctors track an infection over time, Okubo explained, meaning they likely employed the watchful-waiting strategy and had parents bring their kids back in if they didn't improve quickly.

Okubo's team has continued to track pediatricians' antibiotic use, and he noted that they're seeing "spillover effects" among age groups not covered by the incentive. In the under-20 age group, outpatient antibiotic prescriptions fell by 50% between 2011 and 2022. He thinks the incentive is a key driver of this trend, directly reducing prescriptions for the youngest kids while also triggering ripple effects in older groups. (This research will soon be published in a peer-reviewed journal.)

That said, there's room to improve doctors' selection of antibiotics when they are used, as the ratio of broad- to narrow-spectrum drugs is still too high. "Total antibiotic use was reduced, but its quality should be improved further," Okubo said.

The incentive's evolution

While the 800-yen tip has proved significant to clinicians, the incentive represents a very small slice of overall government healthcare spending, which totaled 468 billion yen ($3.1 billion) in 2022.

"This program is not large compared to the whole budget," Dr. Kosuke Sasaki, who works in the MHLW's health insurance bureau, told me. The program's budget has no upper limit, so if the number of claims from clinics increased, there isn't a cap on how many could be paid out. "The number of doctors using this program has increased while the number of antibiotic prescriptions has decreased since the start," Sasaki's colleague Dr. Tomonori Aoki added, noting that the government isn't concerned about how to pay that rising bill.

The program's measurable impact and low price tag may explain its growth over the years.

Every two years, Japan's Ministry of Finance hands the MHLW its slice of the government budget, and MHLW then revises the pricing for drugs, medical devices and healthcare services. The antibiotic incentive falls under this revision process and has been expanded several times.

During its first revision in 2020, the incentive was extended to children under 6. In 2022, ear, nose and throat specialists (ENTs) newly qualified for the incentive; like pediatricians, they treat many acute infections in kids and tend to overuse antibiotics, insurance data suggested. That same year, doctors could start claiming the fee for ear infections and sinus infections.

"I see a tendency for pediatric clinics to avoid prescribing antibiotics, but I do see some ENT clinics prescribing antibiotics carelessly," Shibata, the clinic owner in Asakusa, Tokyo, told me. So ENTs seem to be a logical next target.

In 2024, a separate, facility-level incentive was introduced as a complement to the 800-yen incentive. It encourages clinics to submit data to a government database that tracks antibiotic use. If first-line, narrow-spectrum antibiotics make up a certain percentage of the clinic's overall prescriptions, that clinic earns extra money, Okubo explained.

Ultimately, the 800-yen incentive helped put AMR on the radar of doctors who didn't take it as seriously as experts like Kato, who told me "AMR is kind of my life's work." Kato and researchers like Okubo see the program as a success, although they pointed to room for improvement in antibiotic selection. Ministry officials like Sasaki and Aoki said the program is easy to implement and makes a difference. Clinic doctors like Shibata and Miyahara appreciate the incentive and use it consistently. All in all, at just $5 a claim, the incentive has been remarkably effective.

In speaking with experts in Japan and the U.S., I've learned that U.S. doctors have historically faced the same pressures and showed similar lapses in antibiotic use that Japanese doctors have. However, the U.S. does not have an incentive program like Japan's. Should it launch one?

In the next installment of this series, I'll explore a central feature of this problem: the motivations behind pediatricians' antibiotic misuse. What are they, and do those motivations differ between doctors in the U.S. and Japan? Answers to those questions will help determine whether a similar incentive might have the same impact in both places.

The wreck of a Japanese prison ship that was sunk by U.S. warplanes and went down with more than 1,000 Allied prisoners of war in 1944 has been discovered in the Philippines.

The vessel was one of the notorious "hellships" used by the Japanese to ferry POWs between work camps. Many of the prisoners who died when the ship sank had worked on the infamous Burma-Thailand "Death Railway."

"Sadly, a lot of these prisoner transport ships were sunk by the Allies," expedition leader and American TV show host Josh Gates told Live Science. "The ships were painted to just look like military vessels, and they were inside the Japanese convoys — so the Allies thought they were legitimate military targets."

Gates teamed up with the Hellships Memorial Foundation, a U.S.-registered non-profit based in Subic Bay in the Philippines, to investigate the sinking of the hellship Hōfuku Maru. Its wreck had never been found, probably because searchers were guided by incorrect U.S. records to look too far north, he said.

But Japanese wartime records were more precise about the wreck's location, helping the team find the remains of the Hōfuku Maru in January, Gates said. His team has since made five dives to the wreck, which sits a few miles off the west coast of the main Philippines island of Luzon at a depth of about 160 feet (50 meters).

Prison ships

Japan used more than 130 hellships during World War II, but the wrecks of only a few have been found. Many hellships, including the Hōfuku Maru, were converted freighters. The Hōfuku Maru was used as a prison ship from 1942 until its sinking about two years later.

Gates said the vessel was part of a Japanese military convoy sailing from the Philippines to Japan when it was attacked on Sept. 21, 1944. U.S. warplanes had spotted the convoy, and one dropped a torpedo that cut the Hōfuku Maru in half. It quickly sank.

But the ship had roughly 1,200 Allied POWs on board, from the British and Dutch armies, many of whom had been forced to work on the Death Railway. Some were able to swim ashore, but they were recaptured by the Japanese. About 1,040 died in the sinking, Gates said.

War captives

The 1929 Geneva Convention placed strict limits on the use of prisoners of war for labor, but Japan was infamous for flouting these rules during World War II, claiming that it never ratified the convention and that wartime made POW labor important. Japan used POWs for slave labor on railways and docks, as well as in factories and mines. Of the roughly 132,100 prisoners captured from the United States and United Kingdom armies, nearly a third of them — about 35,000 people — died of exhaustion, malnutrition and disease.

Gates said the Japanese hellships used to ferry thousands of POWs between work camps were miserable places themselves: there was little light, air or food, and prisoners might be kept there for months. Human remains have been identified on the newfound wreck, and it will now be considered a war grave, he said. International conventions aim to prevent such wrecks from being disturbed.

The team first spotted the wreck with sonar, and then dove to identify parts of the structure that confirmed it as the Hōfuku Maru. They also mapped the wreck with a remotely operated underwater vehicle, which helped them determine that the ship had split into separate parts, just as accounts of the sinking had reported.

The Hellships Memorial Foundation would now work to try to locate the families of the victims, Gates said.

Scientists in Japan have discovered a way to transmit data at a speed of 112 gigabits per second (Gbps) at a specific spectrum band that's vital for the build-out of next-generation 6G wireless networks.

To achieve this breakthrough, the researchers developed a new kind of terahertz wireless communication system driven by microcombs — special photonic devices fitted onto microchips that generate optical frequencies for wireless networks. When used with high-order modulation techniques — advanced ways to enable higher data-transfer rates in limited bandwidth — the team delivered these blistering wireless communication speeds in the 560 gigahertz spectrum band.

Achieving such speeds — at a frequency above 420 GHz for the first time — showed how this system can overcome the limitations of signal power and noise that plague conventional electronics at these ultrahigh frequencies, thereby limiting them to much slower data rates. The researchers outlined their findings May 16 in the journal Communications Engineering.

"This result represents a major step toward practical 6G wireless systems and ultra-high-speed mobile backhaul," said Takeshi Yasui, a professor in Tokushima University's Institute of Post-LED Photonics and co-author of the study, said in a statement.

Let there be light

Although 5G wireless speeds are notably fast, with average speeds of approximately 300 megabits per second (Mbps) in the U.S., work is already underway to engineer and roll out 6G networks across the world. In the future, scientists predict speeds to reach a theoretical maximum of 1 terabit per second — more than 3,000 times faster than today's average 5G speeds and 50 times faster than 5G's theoretical limit.

Commercial 6G networks are expected to launch by 2030 or beyond, but significant work is still needed to build out these networks. But to ultimately support the delivery of 6G, a fast backhaul wireless network that taps into super-high-frequency terahertz waves is needed. These sit in the spectrum band that goes beyond 350 GHz. Below that frequency, the electronic spectrum is already congested with 5G signals and lacks the frequency to deliver large amounts of data at next-generation speeds.

When conventional electronics are used to push into the terahertz spectrum, their electronic signals get blighted by a lack of power or "phase noise" — essentially, fluctuations in a signal — that make it hard to separate desired signals from unwanted ones. This leads to limitations in signal stability and the amount of data electronic signals can carry at frequencies above 350 GHz.

Photonics — the use of light to carry data — is therefore seen as a way to forge a path to 6G networks. But conventional photonic systems have required bulky laser systems that need precise optical alignment to work well, and they are still hindered by phase noise.

To address these challenges, scientists are exploring optical microcombs as a way to generate a series of precise lines of light. Their optical stability minimizes phase noise. However, they need precise optical alignment; in a real-world network deployment, vibrations could disrupt such alignments and thus interfere with established connections.

In the new study, the researchers noted that these microcombs didn't "simultaneously achieve stable signal generation and high-order modulation for high-speed data transmission."

Building bonds

The breakthrough comes from directly bonding an optical fiber to a silicon nitride microresonator – a microcomb photonic structure used to convert laser light into millions of precise laser lines. Combining fiber optics with microcombs bypasses the challenge of precise optical alignment, whereas in more conventional photonic systems, laser light needs to be carefully aligned across multiple axes and stages through the use of optical microscopes so it can be directed into microchips.

To send data using the microcomb system, the researchers generated two optical signal carriers — with high stability and a high signal-to-noise ratio — by injection locking the microcomb with lasers. They coded data into these signals using the QPSK and 16QAM high-order modulation formats — essentially, a way to squeeze as much data as possible into a single wave transmission. Then, they converted the optical signals into the 560 Ghz terahertz wave through a technique called photomixing, before transmitting them to a receiver.

In experiments, they achieved 84 Gbps speeds with QPSK and 112 Gbps speeds with 16QAM. The results mean the team researchers made a compact and stable terahertz signal source capable of data transmission speeds exceeding 100Gbps via a transmitter that's just 0.2 inches (5 millimeters) across. For comparison, a conventional microcomb system is 17.7 inches (450 mm).

They also integrated a temperature control function into the microresonator so it could withstand temperature fluctuations, therefore more reliably reproducing the required optical resonance characteristics.

The researchers plan to find ways to further curtail phase noise and boost the output power of their systems to deliver even faster data-transfer speeds. But the study opens a way to create a technological foundation for an ultra-high-speed wireless backhaul network. Such a network could bypass the need for underground fiber-optic cabling as the backbone for high-speed networks and lead the way to practical 6G deployments.

The samurai of Japan are famous for being skilled warriors who followed a code of honor. In popular culture and museums, samurai are often depicted as men, which raises a question: Were any samurai women?

Female samurai existed and there is some evidence that they fought in battle, several experts told Live Science. But how often they fought is a matter of debate, with some scholars calling it very rare and others suggesting it happened more often.

One important point in answering this question is that the samurai were an entire social class, sometimes called the "bushi" class. Anyone born into this class was a "samurai," regardless of whether they fought or practiced any form of martial arts.

"Any woman born in the samurai status group was a 'female samurai' even if she never picked up a weapon, just as any man born into that status group was a samurai, no matter how wimpy/untrained/etc. he may have been," Sean O'Reilly, a professor of Japan studies at Akita International University, told Live Science in an email.

It's unclear how often female samurai fought in battle, however. Women who fought in battle are sometimes called "onna-musha," which translates to "women warriors."

"I must say, as an historian, that onnamusha ‪—‬ female warriors ‪—‬ were probably not as frequent or as militarily significant as most people today believe," O'Reilly said.

Some particularly good evidence for female samurai participating in battle comes from the late 19th century, near the time when the samurai class was abolished, Diana Wright, who was a professor at Western Washington University, wrote in a 2001 article in the journal "War in History."

At that time, Japan was in a civil war as supporters of the Tokugawa Shogunate, which ruled Japan from around 1603 to 1868, battled those who wanted to overthrow the shogunate and return some of the military governor's powers to the emperor. The Boshin War, as it is sometimes called, lasted from January 1868 to June 1869. During that war, there were a number of recorded instances where female samurai, who fought on the side of the shogunate, engaged in battle, Wright noted in her article.

The shogunate forces were led by the Aizu domain (a regional government in northern Japan), and during the siege of the Aizu's capital of Aizu-Wakamatsu, a group of female samurai formed their own unit known as the "Joshigun."

"Although 20 to 30 women are believed to have made up the unit, the names of only 10 are known," Wright wrote. A 22 year-old woman named Nakano Takeko was the unit's unofficial leader.

Armed with only swords and naginatas (pole weapons with curved blades that can both stab and slash), they fought in a battle at Yanagi bridge against a force equipped with rifles, Wright explained. Records indicate that Nakano Takeko killed five or six men with her naginata before she was shot down. Ultimately, the battle ended in defeat and the surviving members of the Joshigun, along with the male troops, had to withdraw to a castle.

During the time of the Tokugawa shogunate, women of the samurai class were required to undergo martial art training with the naginata so they could defend themselves and their families, Wright noted. The amount of training they received varied, with the women of the Aizu domain tending to receive a larger amount.

Remains of female warriors?

A mound located in Numazu, a city in central Japan, may hold the remains of female samurai who fought in battle, some scholars believe. The mound contains human skulls, along with other skeletal bones, and an analysis of the mound's remains was published in Japanese in 1989 in the Journal of Anthropology. The skulls are from about 105 people; all of them were young adults when they died, and about one-third were women. They date to the 16th century, and scientists interpreted them as being the remains of people who were killed in combat, likely in the Battle of Senbonhama (also known as the Battle of Senbon Matsubara), which was fought between the Takeda and Hojo clans.

This mound is "indicative that women of fighting age fought and died in sixteenth century battles," Thomas Conlan, a professor of medieval Japanese history at Princeton University, told Live Science in an email.

However, Karl Friday, a professor emeritus of history at the University of Georgia, said the mound should be regarded with caution, as we can't be sure everyone buried in it actually fought in a battle. It's possible that some of the people buried in the mound were noncombatants who were killed anyway, Friday told Live Science in an email.

Stories and legends of female samurai

A number of stories refer to female samurai fighting in battle. Perhaps the most famous was Tomoe Gozen, who lived during the late 12th century. Stories say she served a lord named Minamoto no Yoshinaka and fought in the Genpei War, which was fought between the Taira and Minamoto clans between about 1180 and 1185, Thomas Lockley, a law professor at Nihon University who has studied and written extensively about the samurai, wrote in a 2022 article in the magazine Medieval World: Culture & Conflict.

One of the chronicles, called "The Tale of the Heike," says that as "a fighter she was a match for a thousand ordinary men, skilled in arms, able to bend the stoutest bow, on horseback or on foot, ever ready with her sword to confront any devil or god that came her way" (translation by Thomas Lockley).

Another famous woman mentioned in stories was Ōhōri Tsuruhime, who lived circa 1526 to 1543. She became the chief priestess of Ōyamazumi Shrine, located on the island of Ōmishima, after her father and brothers were killed while defending the island from a daimyo (a regional governor) named Ōuchi Yoshitaka, Stephen Turnbull, a historian who has written extensively on the samurai, wrote in his book "Samurai Women: 1187-1877" (Osprey Publishing, 2012). Despite being just 16 years old, she took charge of the island's defense force and defended it from the invaders. During her defense, she claimed to have been aided by the shrine's kami (spirit) and has been compared to Joan of Arc, Turnbull noted.

Some of what's said to be Tsuruhime's armor survives today and is displayed at the shrine. Conlan said that it is a suit of 16th century armor that is "tailored to the female anatomy."

However, Friday said we should be cautious when interpreting stories like these. "We do have stories about female warriors, like Tomoe Gozen, Hangaku Gozen, Ohori Tsuruhime, Ueno Tsuruhime, and a few others, but these women are all semi-legendary — especially with regard to their participation in battles," Friday told Live Science in an email.

Regardless of how accurate the stories are, female warriors became famous. "Mythologizing female warriors of yore began in Japan's Kamakura period [circa 1185 to 1333] and intensified in the Edo period [circa 1603 to 1868], with a huge proliferation of woodblock prints showing women holding naginata and so forth," O'Reilly said. Friday said the "very fact that these women became so famous is a pretty good indication of how uncommon female warriors must have been."

Taboos about women and battle

Friday thinks it would have been very rare for female samurai to engage in battle because it was considered taboo.

"One fascinating primer on military conduct, passed down within a branch of the Hōjō family, enjoined against such things as sharing quarters with women for three days prior to battles, allowing pregnant women or women who had recently given birth to touch a warrior's weapons, riding in boats with female passengers while in route to battle, and even allowing women to look upon the backs of officers departing for campaigns!" Friday said.

"The bottom line is that while there almost certainly must have been at least a few cases of women participating in Japanese battles over the course of [the] 8th to 16th centuries … there's absolutely no good evidence to support the conclusion that women warriors were any more common in Japan than they were in medieval France or ancient Sparta, much less that this occurred often enough to justify calling it a practice or even a phenomenon," Friday said.

While the samurai class was effectively abolished during the 1870s, some of the training practices done by female samurai are still carried out today. Eric Shahan, a Japanese translator who specializes in translating martial arts texts, noted that the Yoshin School (a branch of traditional Japanese martial arts) "still practices Naginata in Kimono, reflecting the fact that women may have to suddenly take up arms — and therefore have no time to change into training gear."

Can you identify these historical objects of war? Test your smarts with our weapons of the world quiz!

Aoshima is a tiny, 0.2-square-mile (0.5 square kilometers) Japanese island in the Seto Inland Sea that is home to around 80 feral cats and three elderly people. It is the best known of 11 "cat islands" in Japan where felines easily outnumber humans.

Due to a lack of economic opportunities and the island's aging human population, it's possible that Aoshima will be completely abandoned by people and inhabited only by cats within the next five years, although the cat population is also in decline.

A decade ago, there were about 200 cats on the island, but a mass spaying-and-neutering program in 2018 reduced the number of cats by more than half, and no kittens are known to have been born there since then. All of the remaining cats are older than 7, and a third have diseases caused by decades of inbreeding, according to The Guardian.

"We just take it one day at a time," Naoko Kamimoto, a resident of the island who is in her 70s and known locally as the "cat mama," told The Guardian in 2024. "But the day will come when there are no people left, and no cats. All we can do is make sure we look after them for as long as we're here."

Aoshima was settled in the 17th century and grew into a sardine fishing community with almost 900 inhabitants. Fishers brought a handful of cats to the island to kill rodents that were destroying fishing nets and increasingly becoming pests. But a decline in the fishing industry in the 20th century forced people to leave Aoshima and relocate to the mainland. Many left their cats behind, and the felines reproduced.

Aoshima's cats are fed by food donations from people around Japan. The felines also eat small animals on the island, but their impact on local wildlife is unclear.

The cats occupy abandoned houses and buildings that have crumbled over the years due to weather events such as typhoons and storms. Kamimoto looks after the cats, feeding them twice per day and administering medication.

"People see images online and think they're being neglected, but nothing could be further from the truth," she said. "Some are blind, some are really thin, and others look normal. But that's the reality for wild animals in a place like this."

A 2023 study analyzed the cats' genetic makeup and found significant differences in their coat-color genes compared with cats on other Japanese islands, explaining why most cats on Aoshima are ginger or tortoiseshell. The research showed that Aoshima's cats are descended from a small founder population, confirming that the felines are likely suffering from the effects of inbreeding.

If humans abandon the island, locals are confident that volunteers and shelters will adopt the cats, The Guardian reported. But for now, the felines are a tourist attraction, with visitors taking day trips to the island by boat and helping to feed the cats.

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The Jomon people living in prehistoric Japan had "little to no" Denisovan DNA, suggesting their ancestors may not have been in contact with this now-extinct group of Eurasian humans, a new study reports.

The finding was part of an investigation into hundreds of ancient and modern genomes to determine when and where modern humans (Homo sapiens) mated with our mysterious Denisovan cousins.

"Surprisingly, we found that individuals in the Japanese archipelago from the prehistoric Jomon period [from around 16,000 to 3,000 years ago] carried the least Denisovan ancestry among ancient and present-day East Asians," the researchers wrote in the study, which was published Oct. 20 in the journal Current Biology.

In addition, the team found that ancient mainland East Asians, for example from China and Mongolia, carried more Denisovan genes than any other Eurasian population. These early East Asians got their high amount of Denisovan ancestry from multiple Denisovan groups before the Last Glacial Maximum (roughly 26,500 to 19,000 years ago), the coldest part of the last ice age, the team found.

Meanwhile, ancient Western Eurasians, such as those in Iran and Georgia, harbored the least Denisovan ancestry, the team reported.

The findings are helping scientists to map out early human migrations and how different groups mixed. "Denisovan DNA represents a powerful marker to reconstruct population history," study co-author Stéphane Peyrégne, an evolutionary geneticist at the Max Planck Institute for Evolutionary Anthropology in Germany, said in a statement.

Mysterious Denisovans

Little is known about the Denisovans, who lived in Eurasia from about 200,000 to 30,000 years ago, but researchers have found a handful of their remains and traces of their DNA in present-day Oceanians, East Asians, Southeast Asians and Indigenous Americans.

To track when and where Denisovan DNA entered the genome of modern humans, the team analyzed the genetic makeup of 115 H. sapiens whose ancient remains were found in the U.S., South America, West Eurasia, Siberia and East Asia. The oldest remains were from an individual who lived roughly 45,000 years ago in what is now Bulgaria, while the most recent remains were from a person who lived 766 years ago in what is now Siberia. They also analyzed the genomes of 279 present-day individuals whose data is recorded in the Simons Genome Diversity Project.

The researchers found the most Denisovan ancestry in roughly 40,000-year-old human remains from China, called Tianyuan, with 0.25% of their genome coming from Denisovans. Analyses revealed Tianyuan's DNA came from multiple different Denisovan groups.

The researchers were surprised to find that Japanese people from the prehistoric Jomon period had very little Denisovan ancestry, with one individual who lived 3,755 years ago sporting one-sixth to one-eighth of the Denisovan DNA found in present-day East Asians. (Modern East Asians have around 0.1% Denisovan DNA).

However, Denisovan genes eventually found their way into Japan. People from the Kofun period in Japan (from around A.D. 300 to 710) had more Denisovan DNA than Jomon individuals, with these genes potentially entering genomes following the mass migration of East Asians into Japan during this period.

For now, it's unclear why the Jomon had little Denisovan ancestry, but the team has ideas.

It may be that "some [modern human] groups took different routes during the early dispersals in East Asia," study first author Jiaqi Yang, a doctoral researcher of evolutionary genetics at the Max Planck Institute for Evolutionary Anthropology, said in the statement. "Or, Denisovans were so sparsely distributed that interactions with them were rare."

The researchers cannot be sure on the exact scenario because the data available are limited. Currently, the oldest Jomon genome is only around 9,000 years old, but there is evidence of modern humans living in the Japanese archipelago from around 32,000 years ago. Genetic data from that missing 23,000-year period "might help resolve the early population history in the region," the authors wrote in the study.

Human evolution quiz: What do you know about Homo sapiens?

Scientists in Japan now believe that liquid water once flowed through the heart of the near-Earth asteroid Ryugu, after researchers detected something unusual in the samples of the space rock that were returned to our planet five years ago.

The surprising findings also have potential implications for how Earth acquired its own water, the researchers say.

162173 Ryugu is a roughly 3,000-foot-wide (900 meter) asteroid that orbits the sun every 474 days on a trajectory that frequently overlaps with Earth's. It is unlikely to ever hit our planet, but it is still large enough and comes close enough to us to be considered "potentially hazardous" by NASA.

Ryugu was visited by Japan's Hayabusa2 mission between 2018 and 2019, which deployed a probe that landed on the spinning top-shape space rock and collected samples that were later returned to Earth in December 2020.

In a new study, published Sept. 10 in the journal Nature, researchers unearthed chemical irregularities within these samples, which they say can currently be explained only by the historic presence of flowing water within the asteroid.

"We found that Ryugu preserved a pristine record of water activity," study lead author Tsuyoshi Iizuka, a geochemist at the University of Tokyo in Japan, said in a statement. There is also "evidence that fluids moved through its rocks," he added. "It was a genuine surprise!"

Related: Key building block for life discovered on distant asteroid Ryugu — and it could explain how life on Earth began

The new findings emerged after the team analyzed the radioactive isotopes — rare versions of elements with an altered atomic mass — of lutetium (Lu) and hafnium (Hf) within the samples.

Lu-176 naturally decays into Hf-176 via beta decay, in which an element spits out charged subatomic particles, such as electrons or positrons, transforming them into something else. By working out the ratio of Lu-176 to Hf-176 and comparing it to the half life of Lu-176 — the time taken for half a sample of the isotope to naturally decay — the team aimed to work out how old the samples were.

But when they carried out their analysis, the researchers found that there was far too much Hf-176 in the samples. The researchers argue that the only thing that could properly explain this result was that ancient liquid water had washed away a majority of Lu-176 within the samples, which could have started happening shortly after Ryugu was born.

A watery past

"The most likely trigger [for the water] was an impact on a larger asteroid parent of Ryugu, which fractured the rock and melted buried ice, allowing liquid water to percolate through the body," Izuka said.

Recent analysis from the James Webb Space Telescope (JWST) had suggested that Ryugu's parent asteroid may have also spawned the asteroid Bennu, which was visited by NASA's OSIRIS-REx mission that later returned samples of the asteroid to Earth in September 2023. However, similar signs of flowing water have not been seen within Bennu's samples so far, creating uncertainty about the asteroids' respective origins.

Given that Ryugu likely had flowing water, the researchers also believe that its parent asteroid may have contained ice for at least a billion years after the solar system was formed, which is far longer than most asteroids were thought to be able to hold onto their water.

"This changes how we think about the long-term fate of water in asteroids," Izuka said. "The water hung around for a long time and was not exhausted so quickly as thought."

It is widely accepted that a majority of Earth's water likely came from impacts with asteroids, comets or other planetesimals in the early days of the solar system. The new findings hint that asteroids could have played a much larger role in this process than previously thought, potentially delivering up to three times more water to our planet than expected, the researchers claim.

The study team is now planning to analyze veins of phosphate within the samples, which could pin down a more accurate age for the water that flowed through Ryugu, and look more closely at the isotopes from asteroid Bennu to see if it too has signs of flowing water, according to Live Science's sister site Space.com.

The Narusawa Ice Cave is a lava tube that is brimming with icicles and ice pillars at the base of Mount Fuji in Japan.

Lava tubes are natural tunnels that form beneath solidified lava flows after a volcanic eruption. Lava hardens faster in the top layers of a lava flow, where the molten rock comes into contact with cool air, than in the middle layers, where it stays red hot and fluid. As a result, when a volcano stops erupting, the core of a lava flow drains away while the outside hardens, leaving an empty conduit, or cave.

The Narusawa Ice Cave is one of several caves that formed during a violent eruption of Mount Fuji in A.D. 864. The eruption took place on the northeast side of the volcano, with lava spewing from a new vent called Mount Nagao rather than from Mount Fuji's central summit crater.

The eruption lasted 10 days and created the large lava plain that's now covered by the Aokigahara Forest, a dense woodland also known as the "Sea of Trees." The blast also split a lake in half, carving out two of the five Fuji volcanic lakes.

The ice cave is one of the three largest caves in this area, along with Fugaku Wind Cave and Lake Sai Bat Cave (also called Lake Saiko Bat Cave). Narusawa Ice Cave is 490 feet (150 meters) long and up to 12 feet (3.6 m) high, according to Wind Cave & Ice Cave, the company that manages and offers tours of the cave. The average temperature in the cave is only slightly above 37 degrees Fahrenheit (3 degrees Celsius) due its particular geology, meaning that any moisture is likely to freeze, especially in the winter.

Water that drips from the ceiling of the cave forms stalactites and stalagmites that meet in the middle during the coldest months. The best time to visit Narusawa Ice Cave is in winter or early spring, when these ice pillars can reach up to 1.6 feet (0.5 m) thick and 10 feet (3 m) tall, according to Wind Cave & Ice Cave.

Related: See what would happen to Tokyo if Mount Fuji erupted 'without any warning' in new AI-generated video

The cave is a tourist attraction, but historically, it was used to keep seeds and silkworm cocoons cool. People carved rectangular blocks out of the ice pillars, which they then stacked to create an icebox or refrigerator of sorts, according to Wind Cave & Ice Cave.

"To prevent growth of the cocoons and to preserve the quality of seeds and promote budding, they were stored in a refrigerated environment," the company states on its website.

The cave also holds the remains of ancient trees, which were knocked down by lava flows during the A.D. 864 eruption, pictures on the website show.

The Narusawa Ice Cave sits just half a mile (800 m) east of Fugaku Wind Cave, which extends much deeper belowground, boasts impressive lava formations and houses unusual moss colonies, according to the Japan National Tourism Organization. There is no echo in the wind cave because the walls of pure basaltic rock absorb sound — and unlike in the ice cave, there isn't any frozen water for sound waves to bounce off of.

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A viral video created with artificial intelligence (AI) shows the catastrophic impact that a volcanic eruption at Mount Fuji could have on Tokyo, Japan, and its 37 million inhabitants. Fortunately, the informational video is not timed to any increased risk of an eruption — it's merely a public service announcement tied to Japan’s Volcanic Disaster Preparedness Day 2025.

The AI-generated video, released Aug. 22 by the Tokyo Metropolitan Government, warns of the speed with which volcanic ash could travel from the volcano to Japan's capital city before raining down on its roads, buildings, railways and other infrastructure. Clouds of debris from Mount Fuji could reach Tokyo in just one to two hours, subtitles beneath the video read, paralyzing the city's transport networks, cutting power supplies and affecting the respiratory health of millions of people.

"The moment may arrive without any warning," the subtitles, translating the video's narration from Japanese to English, say. "If Mt. Fuji erupted, volcanic ash may fall on Tokyo and impact us in a wide variety of ways."

In the video, a woman receives an alert on her phone warning of an eruption at Mount Fuji, which is located 60 miles (100 kilometers) southwest of Tokyo's city center. The clip then takes the viewer on an AI-generated tour of the potential impacts of volcanic ash on Tokyo's transport links, power lines, water supplies, residential buildings and inhabitants.

"It only takes a minimal accumulation of ash on runways and rails to render planes and trains unusable," the subtitles in the section of the video about transport infrastructure say. "A small amount of ash on roads may impact the operation of 2WD [two-wheel drive] vehicles, as the ash fall limits visibility and increases the risk of slippage, creating hazardous driving conditions."

Large amounts of ash may block Tokyo's sewers, contaminate freshwater supplies, crush power lines and collapse wooden roofs, according to the video. The city could also be plunged into darkness as ash particles block the sun, and access to food and other essentials may be temporarily suspended. Additionally, people might suffer adverse health effects from inhaling the particles, with pre-exiting respiratory conditions worsening with exposure.

Related: Supervolcanic 'hell' caldera in Japan is home to 17 different volcanoes — Earth from space

Mount Fuji is Japan's highest peak, measuring 12,389 feet (3,776 meters) tall. The last time the volcano erupted was in 1707, and the subsequent ashfall lasted for two weeks, according to the video. While Mount Fuji used to erupt about every 30 years, it has now been dormant for 318 years, but some experts think that it could blow at any moment.

However, the timing of the video is unrelated to any signs of an eruption, and there is no suggestion that Mount Fuji is close to exploding, the Tokyo Metropolitan Government said in a statement seen by CNN. "The simulation is designed to equip residents with accurate knowledge and preparedness measures they can take in case of an emergency," government officials wrote in the statement.

Preparedness measures include stocking up on food and first aid supplies. In the video, parents show their child a pantry filled with canned food, water and medicines ready in case of an emergency.

The video was released for Volcanic Disaster Preparedness Day 2025, but this isn't the first time Tokyo's government has warned of the risk from Mount Fuji, according to CNN. In March, officials published guidelines recommending that people stock two weeks' worth of essential supplies in their homes at all times.

The Japanese government has been modeling earthquake and volcanic eruption scenarios for years, yet these investigations don’t coincide with specific risks from Mount Fuji or other geological features, Naoya Sekiya, a professor and risk communication expert at the University of Tokyo, told NBC News.

"There's no particular significance to the timing," Sekiya confirmed.

Japan is home to 111 active volcanoes — about one-tenth of the world's total — due to its position on the Pacific Ring of Fire, a horseshoe-shaped belt of volcanoes around the Pacific Ocean. The country is located on the border between four tectonic plates that grind against each other and often collide, triggering swarms of earthquakes and volcanic eruptions.

Perhaps the best known natural disaster to strike Japan was the Tohoku earthquake and tsunami in 2011. The magnitude 9 earthquake was the strongest in Japan's recorded history, with warnings going out to Tokyo residents just one minute before the shaking began.

During the Kofun period (300 to 710) of Japanese history, people buried the dead in large mounds with many grave goods. Scattered around the mounds were objects called "haniwa" — clay cylinders topped with clay figures, used in offerings for the dead.

These two haniwa, known as the "Dancing People" or "Haniwa Terracotta Dancers," are in the collection of the Tokyo National Museum. They were discovered in 1930 during the excavation of an ancient cemetery in Saitama prefecture, north of Tokyo, and are thought to have been made about 1,500 years ago.

According to the Tokyo National Museum, haniwa were made throughout the Kofun period and were used exclusively as tomb decorations. Originally simple clay cylinders, haniwa became more elaborate over time, as the cylinders were topped with figures that included humans, animals, houses, armor and boats. They were used to mark grave boundaries, and some haniwa were thought to hold the souls of the deceased.

The Dancing People haniwa are especially striking because of their simplicity. Their mouths and eyes are holes, which make them appear to be wide open. Their arms are stick-like, and their upper bodies end in a cylinder base below a thin belt. Their curving arms and open mouths have led some researchers to conclude they are singers or dancers.

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In a 2008 study of the Dancing People, archaeologist Yoshio Negita suggested that the pair may be a man and a woman. The smaller one has clay on the sides of its head, suggesting a peasant hairstyle, so haniwa may represent a male farmer, Negita proposed. Another theory, put forward by archaeologist Yoshimichi Tsukada in a 2007 study, suggested that the haniwa may depict two male herders holding the reins of their horses.

Thousands of haniwa have been discovered from ancient Japanese graveyards, as each tomb was surrounded by many of these objects.

But video game enthusiasts may recognize haniwa from a 21st century context: In the game "Animal Crossing," the "gyroids" that a player can dig up are called "haniwa" in the Japanese version and are based on the ancient clay sculptures.

Japan has switched on the first quantum computer that has been designed and built with components from the country. The system is now ready to take on workloads from its base at the University of Osaka’s Center for Quantum Information and Quantum Biology (QIQB).

The new system, which went live on July 28, replaces all previously imported components with homegrown technologies, University of Osaka representatives said in a statement. It will also run on open-source software developed in Japan, called the Open Quantum Toolchain for Operators and Users (OQTOPUS).

The system uses a quantum chip with superconducting qubits — quantum bits derived from metals that exhibit zero electrical resistance when cooled to temperatures close to absolute zero (minus 459.67 degrees Fahrenheit, or minus 273.15 degrees Celsius). The quantum processing unit (QPU) was developed at the Japanese research institute RIKEN.

Other components that make up the "chandelier" — the main body of the quantum computer — include the chip package, delivered by Seiken, the magnetic shield, infrared filters, bandpass filters, a low-noise amplifier and various cables.

These are all housed in a dilution refrigerator (a specialized cryogenic device that cools the quantum computing components) to allow for those extremely low temperatures. It also comes alongside a pulse tube refrigerator (which again cools various components in use), controllers and a low-noise power source.

OQTOPUS, meanwhile, is a collection of open-source tools that include everything required to run quantum programs. It includes the core engine and cloud module, as well as graphical user interface (GUI) elements, and is designed to be built on top of a QPU and quantum control hardware.

Related: Scientists hit quantum computer error rate of 0.000015% — a world record achievement that could lead to smaller and faster machines

A new frontier of computing

Quantum computing has the potential to outpace the world's fastest supercomputers and solve problems by making calculations and running simulations far beyond what technology is capable of today. Scientists speculate that quantum computers could be useful in drug discovery, easing traffic flows through a city, and finding the best delivery routes for a logistics company, among plenty of other endeavors.

This is because it can process calculations in parallel, rather than in sequence, by tapping into the weird laws of quantum mechanics. The idea is that the more qubits added to a system, the more powerful the system becomes.

However, there are plenty of barriers to simply adding qubits to quantum computers — in particular, scientists are trying to solve the extremely high error rate that occurs during calculations. For this reason, most research is currently centered on quantum error correction (QEC).

Japan's first quantum computer was showcased at Expo 2025, held in Osaka from Aug. 14 to Aug. 20..At the exhibition, organizers showcased key components in the quantum computer. Visitors could connect to the system remotely through the cloud and run basic quantum programs. The exhibit also included interactive elements enabling visitors to explore quantum entanglement and other quantum phenomena.

Researchers in Japan say they have set a new world record for the fastest internet speed, transmitting over 125,000 gigabytes of data per second over 1,120 miles (1,802 kilometers).

That's about 4 million times the average internet speed in the U.S. and would allow you to download the entire Internet Archive in less than four minutes, according to some rough estimates. This is also more than twice the previous world record of 50,250 GB/s, previously set by a different team of scientists in 2024.

To achieve this new speed — which has not been independently verified — the team developed a new form of optical fiber to send information at groundbreaking speeds over roughly the distance between New York and Florida.

Details about this achievement were presented April 3 at the 48th Optical Fiber Communication Conference in San Francisco, according to a statement from Japan's National Institute of Information and Communications Technology.

1,120 miles of travel

The new type of optical fiber is equivalent to 19 standard optical fibers in its data transmission capacity. The new optical fiber is better suited to long-haul transmission than existing cables because the centers of all 19 fibers interact with light in the same way, so they encounter less light fluctuation, which results in less data loss.

The new cable squeezes 19 separate fibers into a diameter of five-thousandths of an inch (0.127 millimeters), which is the same thickness as most existing single-fiber cables already in use. This effort means the new cable can transmit more data using existing infrastructure.

Related: Internet history timeline: ARPANET to the World Wide Web

In March 2023, the same team reached similar transmission speeds but across less than a third of the distance covered in the new achievement. The biggest hurdles to increasing the range were further reducing data loss, which can happen over long distances, and figuring out how to amplify the data, according to the statement.

Solving these challenges led to increased signal strength, which allowed the data to travel a longer distance.

For this demonstration, the data ran through a transmission system 21 times, finally reaching a data receiver after traveling the equivalent of 1,120 miles.

This record shows technological progress toward developing long-distance, high-capacity, scalable optical communication systems, which could address the increasing global demand for data, the statement suggests.

Data traffic volume worldwide is expected to increase significantly in the near future, so new communications infrastructure may be necessary, the statement suggests. Next, the team hopes to explore practical applications in the telecommunications sphere.

Scientists have discovered evidence of an ancient tsunami in Japan — which is hidden in tree amber that dates to the age of the dinosaurs. The amber samples are deformed in a particular way that suggests trees and plant debris were rapidly swept out to the ocean and sank to the seafloor around 115 million years ago, the researchers said, which the team interpreted as evidence of one or more tsunamis. The scientists published their findings today (May 15) in the journal Scientific Reports.

Scientists typically estimate when tsunamis happened in the past using geological evidence such as giant fossilized boulders that were swept away and deposited onto coasts, or by looking at abrupt changes in sediment deposits near coastlines. However, it can be difficult to differentiate tsunami traces in the fossil record from severe storms, which leave similar deposits.

Amber, which is fossilized tree resin — a fluid produced by trees — can also be transported to the ocean when a tsunami sweeps trees and plant debris out to sea, leaving behind a record of the tsunami event.

In the new study, the researchers analyzed amber-rich silica deposits from the Shimonakagawa Quarry in northern Hokkaido, Japan, which were deposited sometime between 116 million and 114 million years ago, during the Early Cretaceous period (145 million to 100 million years ago), when this region was deep seafloor.

The team used fluorescence imaging — a technique that photographs the amber samples while shining ultraviolet light onto them — to observe the amber's structure.

The amber samples showed a pattern similar to what geologists call "flame structures," a deformation that happens when soft sediment is deposited somewhere and changes shape before fully hardening — resulting in upward-pointing, flame-shaped tongues between the sediment layers. Amber deposits more commonly form other shapes, as tree resin dries when exposed to air.

The research team interpreted the flame structures to mean the amber was suddenly swept out from the land to the ocean by one or more tsunamis, without being exposed to the air (which would have hardened it), then sank to the seafloor. The amber would have then been covered by a layer of silt and preserved for millions of years.

"Identifying tsunamis is generally challenging," and it was not immediately apparent that tsunamis were behind the unusual amber samples, study co-author Aya Kubota, a paleontologist at Chuo University in Tokyo, told Live Science in an email. "By combining detailed field observations with the internal structures of amber, we were able to conclude that the most plausible cause was tsunamis."

Other evidence from the area backed up this hypothesis, including signs of a nearby landslide around the same time that may have been caused by an earthquake; large chunks of mud seemingly ripped up by the destruction of the seafloor; and large tree trunks on what was at the time the seafloor. Severe storm waves would not have affected the seafloor in this way, and if the tree trunks were stacked slowly over time they would have shown evidence of erosion, which these trunks did not — meaning all the evidence points to a huge amount of plant debris being transported quickly and suddenly to the seafloor.

The researchers suggested that looking at ocean floor geological and fossil evidence — that is, beyond just coastal evidence — paints a more complete picture of previous tsunamis, and that examining amber deposits can provide information that helps differentiate tsunamis in the prehistoric record from severe storms.

"Resin offers a rare, time-sensitive snapshot of depositional processes," Kubota said. Although the study of amber has typically focused on organisms like insects trapped inside samples, "the emerging concept of 'amber sedimentology' holds exciting potential to provide unique insights into sedimentological processes," Kubota added.

For many people, the word "ninja" may bring up an image of a person clad almost entirely in black. But is that what they actually wore?

Live Science contacted experts and examined historical texts to learn how these famous warriors really dressed. Ninjas, also known as shinobi, operated throughout Japan and performed espionage, sabotage and, on rare occasions, assassinations. They also occasionally took part in battles. When exactly they originated is unclear, but ninjas operated in Japan until the late 19th century.

When it came to their wardrobe, ninja wore disguises that made it easier to spy and otherwise blend in with the population, experts said.

"Scouts watching an enemy encampment apparently wore simple peasant or merchant clothing," said Balázs Szabó, a researcher in the Department of Japanese Studies at Eötvös Loránd University in Hungary. "Spies infiltrating enemy castles had to wear clothing that helped them to merge in with the inhabitants of the castle."

The all-black uniform that modern-day people imagine ninja wearing comes from puppet theater. "The all-black hooded costume [is] derived from the dress wore by puppet-mover artists in the Japanese puppet theatre" Szabó said.

Related: Did Roman gladiators really fight to the death?

Eric Shahan, a Japanese translator who specializes in translating martial arts texts, agreed that ninja would have worn disguises. "Ninja would most likely wear clothing matching the place they were trying to infiltrate," Shahan said in an email. "This would include carrying everyday items. Wearing all black would most certainly draw attention."

If ninja had to fight in a battle, they likely would have worn armor, according to Iwata Akihiro, an archaeologist and curator at the Saitama Prefectural Museum of History and Folklore in Japan. They would have worn "simple armor which is easy to move [in]," Akihiro said.

Straw-hat ninja

"The Shōninki" — a book written by Natori Masazumi, a ninja who lived in the 17th and early 18th century — provided instructions on how ninja should operate. According to the book, ninja need to be able to change disguises as needed.

"The art of the shinobi consists of learning tricks that can be used at critical moments, such as being able to disguise himself as a priest, a wandering monk, a woman, or a girl of the mountains, and, hidden in the night, perform espionage" (translation by Jon E. Graham), Masazumi wrote in the book, whose full title is "Shoninki: The Secret Teachings of the Ninja: The 17th-Century Manual on the Art of Concealment" (Destiny Books, 2010).

Masuzumi suggested disguises that are good for certain tasks. For instance, dressing up as a Buddhist monk is good for getting close to people, dressing up as a merchant is better if you want to freely mingle in a crowd, and a street entertainer is an appropriate disguise if you want to blend into a crowd.

Masazumi recommended that, if possible, a ninja should wear a straw hat — known as an "amigasa" — as part of their disguise. "Thanks to the amigasa it is easy to hide your face and transform your profile," he wrote. "It is very easy to observe people from underneath your amigasa." Wearing a cape or raincoat can make it easier to observe people and change disguises quickly without being noticed, he added.

The color of a ninja's clothes should reflect their surroundings. "The environment can assume the most varied appearances and you should choose the most appropriate color in order to blend with it," Masazumi wrote. Other suggestions include carrying a piece of cloth that, depending on the situation, can be used as a belt, a headband or a face mask.

"Prepare yourself well by using these different disguises, based on the circumstances," Masuzumi wrote. "It is essential to know yourself, to study the place where you are staying, and to conceal yourself there with a serene heart."

A large proportion of East Asian people carry unique versions of the lactase gene that enables humans to digest the sugars in milk, new research hints.

These genetic variants were likely inherited from humans' extinct cousins, the Neanderthals, tens of thousands of years ago, according to a study published Mar. 10 in the journal PNAS. And it may be that the variants offered an evolutionary advantage by helping early hunter-gatherers thwart infections, new data suggest.

In some people of European or African descent, the lactase gene helps carriers digest a sugar called lactose in milk after they're weaned off of breast milk; this phenomenon is known as "lactase persistence." Many people who carry alternative versions of the gene can't continue breaking down lactose after infancy, so they become lactose intolerant.

The versions of the lactase gene behind lactase persistence are believed to have emerged in populations in Europe and Africa between 5,000 and 10,000 years ago, around the same time humans on these continents began rearing animals and consuming their milk.

Related: Papua New Guineans, genetically isolated for 50,000 years, carry Denisovan genes that help their immune system, study suggests

This has led scientists to theorize that the lactose-tolerance variants were selected for within these populations, meaning they became more common over the course of evolution because they offered an advantage. In this case, they may have increased survival rates by allowing adults to absorb nutrients from milk.

However, until now, little was known about the genetic mechanisms behind lactase persistence and lactose intolerance in East Asians. About 65% of adults worldwide are thought to be lactose intolerant, but this figure rises to between 70% and 100% in East Asian populations.

In the new study, scientists compared thousands of genomes sampled from modern humans, including those with East Asian, European or African ancestry. The data came from individuals in a range of countries, such as China, Japan, Spain, Italy and Nigeria.

The analysis revealed that around 25% of the people with East Asian ancestry carried versions of the lactase gene that are not found within the European or African populations. That's around the same proportion of people who have lactase persistence in East Asian populations. These genetic variants trigger an increase in the activity of the lactase gene in the body, the researchers found.

At first glance, this suggests that these genetic variants may have also been selected for during evolution for dietary reasons, the researchers said. However, further analyses in the same study revealed that this may not have been the case.

Indeed, the researchers went on to compare samples of East Asian genomes with the genome of a Neanderthal who lived in the Altai Mountains in Siberia around 120,000 years ago. This led them to discover that the East Asian variants of the lactase gene were likely inherited by hunter-gatherers from Neanderthals as a result of interbreeding events between the two groups.

Neanderthals and Homo sapiens are known to have interbred on multiple occasions over the millennia. This happened after both species came into contact with one another following the migration of the latter group out of Africa into Eurasia, possibly up to 250,000 years ago.

The new results suggest that the lactose-intolerance variants started being selected for between 25,000 and 28,000 years ago — more than 10,000 years before dairy culture emerged in the Altai Mountain region.

In other words, the variants emerged before people in the region started regularly consuming milk. This suggests that the selective pressure on these variants was not related to improving people's ability to digest lactose.

To figure out what other advantages these variants might offer, the team scoured a database chronicling gene activity in different cells. They discovered that the lactase gene variants seen in East Asian people altered the activity of three genes in immune cells, causing them to expand in number.

Based on this result, the study authors think it's possible that these variants were selected for because they somehow enhanced the ability of East Asian hunter-gatherers to combat infections.

"Neanderthals — having inhabited Eurasia for approximately 400,000 years — likely carried alleles [genetic variants] adapted to local pathogens and environmental challenges," study co-author Shuhua Xu, a professor of human population genetics at Fudan University in China, told Live Science in an email.

Taken together, the findings imply that variants of the lactase gene may have been selected for different reasons across the world, the researchers concluded. These findings may prompt scientists to question why selection of the lactase gene occurred in European and African populations, they added; perhaps the answer isn't solely about drinking milk.

Engineers in Japan have switched on the world's first hybrid quantum supercomputer.

The 20-qubit quantum computer, called Reimei, has been integrated into Fugaku — the world's sixth-fastest supercomputer. The hybrid platform will work to tackle calculations that can take classical supercomputers much longer to process.

The machine, which is housed at the Riken scientific institute in Saitama, near Tokyo, will be used primarily for physics and chemistry research, representatives from Quantinuum, the makers of Reimei, and Riken said in a joint statement.

Quantum computers could one day overtake classical computers, with the potential to complete calculations in minutes or seconds that would otherwise take today's most powerful machines millions of years. However, until quantum computers are large and reliable enough, scientists say that integrating their capabilities into supercomputers can be a stopgap.

Unlike most quantum computers that use superconducting qubits, Reimei uses trapped-ion qubits. This involves isolating charged atoms, or ions, in an electromagnetic field — known as an ion trap — and using lasers to precisely control their quantum state.

Related: Google's Sycamore quantum computer chip can now outperform the fastest supercomputers, new study suggests

This enables the scientists to manipulate the ions so they can be used as qubits that store and process quantum information. Trapped ion qubits encourage more connections between qubits and longer coherence times, whereas superconducting qubits have faster gate connections and are easier to fabricate on chips.

Riken representatives said they chose Quintinuum's quantum computer for the integration because it has a unique architecture that physically moves qubits. This process of "ion shuttling" allows qubits to be moved around a circuit as required, allowing for more complex algorithms.

Error-correcting system

Qubits are inherently "noisy," so to effectively scale up quantum computers, scientists are developing error-correction techniques to increase the fidelity of qubits.

In Reimei, the physical ion qubits have been grouped to create "logical qubits" — meaning a set of physical qubits that store the same information in several places. Logical qubits are a key route to achieving a desired reduction in qubit errors, because distributing the information in different places spreads out the points of failure, meaning a qubit failure does not disrupt an ongoing calculation.

Quaintinuum previously achieved a breakthrough in creating a logical qubit with an error rate 800 times lower than physical qubits, which it integrated into its quantum computing processors.

While Reimei-Fugaku is the first fully operational, integrated hybrid system, other companies have previously tested such systems. In June 2024, IQM integrated a 20-qubit quantum processor into the SuperMUC-NG supercomputer in Garching, Germany.

That system, however, is still in the testing phase, with no confirmed public date when it becomes fully operational. In October, IQM representatives announced the company would integrate a 54-qubit system into the supercomputer in the latter half of 2025 followed by a 150-qubit chip in 2026.

The 20,000-year-old fossilized bones of "Ushikawa Man," thought to be some of Japan's most ancient human fossils, are not what scientists believed they were, new research finds.

Instead, they are the bones of an ancient bear.

The fossils were found in the late 1950s in the city of Toyohashi, about 140 miles (225 kilometers) southwest of Tokyo. But Gen Suwa, an anthropologist at the University of Tokyo who led the new project, told Live Science that doubts about the Ushikawa fossils were first raised in the late 1980s, and had continued since then.

The new research, published Dec. 1, 2024 in the journal Anthropological Science, shows beyond a doubt that the bones are from an ancient brown bear, Suwa said in an email.

He added that the bones of bears were rarely found in archaeological sites in Japan from this time, and so Japanese scientists — including the paleontologists who found the fossils in the 1950s — had a limited understanding of what bear bones could look like. Even so, these scientists had made "detailed and very accurate" descriptions, and also collected large numbers of fossilized skeletal remains over several decades, Suwa said.

Related: Ancient bones reveal previously unknown Japanese ancestors

Old bones in Japan

The fossils are named for the Ushikawa district of Toyohashi, where they were unearthed during excavations at a quarry between 1957 and 1959. Suwa said Japanese scientists at that time thought a different bone fragment known as "Akashi Man" was the earliest human fossil from mainland Japan, perhaps more than 780,000 years old; but the fossil was destroyed in an Allied air raid on Tokyo during World War II.

In the 1980s, an anatomical analysis in the 1980s of a plaster cast of the lost Akashi fossil indicated it was probably a fragment of a recent human arm bone that had been washed into a different archaeological layer and then mineralized. That finding led to greater attention on the Ushikawa fossils, Suwa said.

The Ushikawa fossils were initially presented as a humerus bone from the upper arm and the end or head of a femur bone from the leg of a human who had lived more than 20,000 years ago. But in the new study, a visual examination and computed tomography (CT) scan revealed that the supposed human humerus was probably the radius bone from the forearm of a brown bear (Ursus arctos) from about that time, while the head of the femur was also determined to be from a bear, Suwa said.

Prehistoric fossils

The discovery that the Ushikawa fossils are not human means the oldest human fossils found on the Japanese mainland are from a limestone quarry near the Japanese city of Hamakita, about 25 miles (40 km) east of Ushikawa.

They comprise fragments of a human leg bone, arm bone, collar bone and skull that are thought to be from two different people — one who lived about 14,000 years ago and another who lived about 17,000 years ago.

Human fossil remains have also been found on Japan's Ryukyu Islands — also known as the Nansei Islands — situated about midway between Japan and Taiwan. Scientists think the youngest of these fossils date from about 18,000 years ago, while the oldest may date from up to 32,000 years ago.

The latest finding in Japan is not the first time that human and bear bones have been confused: A bone found in a cave in Alaska in the 1990s was once thought to be from a bear, but new research has shown that it is from a Native American woman who lived about 3,000 years ago.

Name: Doban-kun

What it is: A clay tablet

Where it is from: Northern Honshu, Japan

When it was made: Around 1500 B.C.

Related: Dancing dwarf: A 2,300-year-old ancient Egyptian statue of a godlike man with a muscular 6-pack

What it tells us about the past:

This small, clay tablet was likely a tool used to perform rituals at two prehistoric stone rings in northern Japan over three millennia ago. The holes were used for counting and were arranged in the shape of a person.

Doban-kun, which means "flat clay man" in Japanese, is 2.3 inches (5.8 centimeters) tall and 1.5 inches (3.7 cm) wide and weighs about 1.7 ounces (48.4 grams). It was found near the Ōyu Stone Circles, which were built by the Jōmon culture.

The Jōmon period spanned roughly 14000 to 300 B.C. Although there was no large-scale agriculture in this period, the Jōmon culture was largely sedentary and very complex, creating pottery, jewelry, statues and tools from a variety of natural materials, such as stones, bones and antlers.

According to the Ōyu Stone Circle Center, the site was created from dozens of river rocks around 2000 B.C., in the late Jōmon period. The two larger circles were likely used in rituals that helped strengthen social ties among the surrounding settlements, while the smaller circles were made to mark graves. The sundial-like arrangement of the stones suggests that the Jōmon people understood the movement of the sun.

Numerous small clay tablets were found during excavations at the stone circles over the past several decades, but Doban-kun is unique. Researchers think it was created as a tool for counting. The largest hole, representing the person's mouth, is 1; the eyes are 2; the right side of the chest is 3; the left side is 4; and the vertical line of circles in the center of the chest is 5. Circles on the back of the head represent 6.

There is also a hole in the bottom center that connects to the mouth hole via a channel through the clay body. This could mean that Doban-kun is a female figure, Doban-chan ("flat clay woman").

Either way, the tablet has a cute appearance, according to the Ōyu Stone Circle Center, which may have been a popular style at the time. But whether Doban-kun represents a 3,500-year-old example of kawaii, or "cute culture," is still up for debate.

Researchers have discovered the origins of a 200-year-old volcanic eruption that ejected so much sulfur into the atmosphere that it changed the climate and made the sun look blue.

In 1831, the Northern Hemisphere climate cooled by an average of about 1.8 degrees Fahrenheit (1 degree Celsius), coinciding with reports of gloomy, bleak weather and the sun turning different colors. Scientists knew a massive eruption caused this strange event, but the volcano responsible has remained a mystery — until now.

By studying ash deposited in polar ice cores, scientists traced the eruption to Zavaritskii volcano on the extremely remote island of Simushir, which is part of the disputed Kuril Islands between Russia and Japan. During the Cold War, the Soviet Union used a flooded volcanic crater on Simushir as a secret nuclear submarine base, according to a statement released by the University of St Andrews in the U.K.

The researchers' findings, published Dec. 30, 2024 in the journal PNAS, highlight how little researchers know about volcanic activity on the Kuril Islands.

"Eighteen thirty-one is a relatively recent period of time, but we had no idea this volcano was responsible [for the dramatic eruption]," study lead author William Hutchison, a volcanologist at the University of St Andrews, told Live Science. "It was completely off the radar."

Related: Undersea volcano off Oregon coast could erupt this year, geologists predict

The 1831 eruption was one of several 19th-century eruptions linked to the final phase of the Little Ice Age (1800 to 1850), according to the study. The Little Ice Age wasn't an actual ice age — the last true ice age ended 10,000 years ago — but it did mark the coldest period in the last 500 years.

Hutchison noted that there are no written records of direct observations from the 1831 eruption, likely because the Kuril Islands were — and still are — remote and largely uninhabited, often clouded by thick fog. However, the volcano's impact is well documented.

German composer Felix Mendelssohn wrote of "desolate weather" in the summer of 1831 that was "as cold as winter" as he journeyed through the Alps, the researchers said in the statement. Various accounts in the Northern Hemisphere also mentioned the sun turning blue, purple and green as a result of light scattering and absorption by aerosol particles from the volcano's plume. A similar phenomenon was observed after the 1883 Krakatoa eruption, according to the study.

The eruption's knock-on effects may have been deadly: lower global temperatures preceded major famines in India and Japan in the 1830s, according to the study.

"We know with large volcanic eruptions like this one that when you get cooling, you get changes to rainfall, you get changes to crop yield," Hutchison said. "And that has a knock-on effect that there's simply not enough food for people to eat."

To identify the source of the eruption, Hutchison and his team studied the remnants of ash deposited in 19th-century polar ice cores collected from Greenland. The chemical fingerprint of this ash was similar to ash from volcanos in Japan and nearby islands. Hutchison said that the team ruled out Japan as a location for the eruption because of its dense population and well-documented record of volcanic eruptions. That led the researchers to look at the Kuril Islands.

'Eureka' moment

The team found that the ash deposits at Zavaritskii volcano perfectly matched the chemistry of the ash found in the ice cores. Hutchison said this was a "Eureka-type moment" and similar to finding a fingerprint match in crime scene forensics.

"It was really a terrific day," Hutchison said. "One of the best days I've ever had in the lab."

While the team solved the mystery of the 1831 eruption, Hutchison noted that there still isn't any instrumentation monitoring volcanic activity on the Kuril Islands — this is true for most volcanoes around the world.

"If this eruption were to happen today, I don't think we'd be much better off than we were in 1831," Hutchison said. "It just shows how difficult it will be to predict when and where the next big climate-changing eruption will come from."

Some modern Japanese people may have a higher body mass index, or BMI, thanks to DNA they inherited from prehistoric hunter-gatherers.

In a new study, researchers analyzed the genomes of more than 170,000 people living across Japan, from Hokkaido in the northeast to Okinawa in the southwest, and compared this modern DNA with 22 prehistoric Japanese and Eurasian genomes from a previously compiled dataset.

Specifically, the researchers examined how DNA inherited from the Jōmon people, a cultural group of hunter-gatherer fishers who lived in Japan up to 16,500 years ago, may be associated with 80 different complex traits in modern Japanese people. Complex traits are those encoded by multiple genes and include traits such as height, BMI and the amount of oxygen-carrying cells in the blood.

The scientists found that, on average, Japanese people have inherited around 12.5% of their DNA from Jōmon hunter-gatherers. Of all the traits studied, BMI was the only trait significantly associated with Jōmon DNA — meaning individuals with more genetic evidence of Jōmon ancestry were significantly more likely to have a higher BMI than those carrying less of this prehistoric DNA.

Therefore, this DNA may put the individuals who carry it at a higher risk of obesity, the researchers wrote in the paper.

Related: Papua New Guineans, genetically isolated for 50,000 years, carry Denisovan genes that help their immune system, study suggests

BMI is an imperfect measure of body fat, partly because it doesn't distinguish between fat and lean body mass. It's also mostly based on data from white populations, so its health implications don't always generalize to other demographics. Nonetheless, high BMI has been tied to various health risks, such as type 2 diabetes, and the metric is still in widespread use in medicine.

In addition to analyzing DNA from people in Japan, in separate analyses, the researchers focused on people with Japanese ancestry living abroad, including 2,200 East Asian people living in the U.K. These groups showed similar links between Jōmon ancestry and BMI, underscoring the far-reaching effects of this genetic legacy.

The researchers described these findings in a paper published Nov. 12 in the journal Nature Communications. They said the study is a demonstration of natural selection — the driving force behind organisms evolving useful traits over time. What may have been a positive trait in the past can negatively influence disease risk in a modern context, they concluded.

"It is a really important discovery that ancient hunter-gatherer ancestry is likely to play a key role in the health of modern day populations," study co-author Shigeki Nakagome, an assistant professor in genomic medicine at Trinity College Dublin, said in a statement. "The link to an increased BMI could also help to explain some of the disparities in obesity prevalence among Asian populations residing in Western countries."

The researchers found that Jōmon genes were very active in skeletal muscle cells, which enact voluntary movements. Some of these genes had previously been tied to a higher BMI. The team theorized that this DNA may have helped prehistoric hunter-gathers adapt to the high physical demands of their lifestyle.

Previous research has also shown that several of these Jōmon genes may increase bone mineral density, or the concentration of calcium and other minerals in bone. This is a sign that a person exerts elevated levels of physical activity. Having larger muscles and denser bones might bump up a person's BMI.

The new study also provides further evidence to support an emerging theory in population genetics.

For about three decades, many scientists have hypothesized that modern Japanese people originate from two ancestral groups: Indigenous Jōmon hunter-gatherers and migrants from Northeast Asia. However, recent evidence, including data from this new study, is beginning to turn this theory on its head, suggesting that a third ancestral group from East Asia also left their genetic imprint on modern Japanese people.

"I am sure there is much left to discover, both in Japanese populations, and in others across the globe," Nakagome said in the statement.

Ever wonder why some people build muscle more easily than others or why freckles come out in the sun? Send us your questions about how the human body works to community@livescience.com with the subject line "Health Desk Q," and you may see your question answered on the website!

Searchers have located the wreck of one of the few warships that fought for both the United States and its enemy Japan during World War II.

The remains of the destroyer USS Stewart were found in early August at a depth of roughly 3,500 feet (1,065 meters) in the Cordell Bank National Marine Sanctuary, about 50 miles (80 kilometers) northwest of San Francisco.

It was sunk there during target practice in 1946 by rockets from U.S. warplanes and shells from a U.S. warship. But its exact location was unknown, until the wreck was rediscovered by three autonomous underwater vehicles (AUVs) deployed by the marine robotics company Ocean Infinity.

According to The New York Times, the AUVs searched a 37-square-nautical-mile (49 square miles, or 127 square km) area of the seafloor in under 24 hours.

"We covered it very quickly, and in high resolution," Andy Sherrell, Ocean Infinity's director of maritime operations, told the newspaper.

Related: 30 incredible sunken wrecks from WWI and WWII

On both sides

The Stewart started the war as a U.S. destroyer designated DD-224 and was ordered to Borneo in November 1941, shortly before the U.S. entered World War II. It served as an escort vessel with other American warships in the first months of the Pacific War, but it was badly damaged by gunfire from Japanese warships near Bali in February 1942, during the Battle of Badung Strait.

The Stewart managed to return to Surabaya on the island of Java. But the port came under Japanese attack, so the vessel was scuttled — deliberately sunk — by its own crew, who set off explosives in its hull. A year later, however, Japanese raised the sunken warship and it served as a patrol boat for the Imperial Japanese Navy until the war ended in 1945.

The ship again came under U.S. control when Japan surrendered on Sept, 2, 1945. The vessel was briefly recommissioned as DD-224 by the U.S. Navy, but by then it was in poor shape. It was finally decommissioned in May 1946 and then used for target practice.

Ghost ship

The Stewart was known as the "Ghost Ship of the Pacific" and had been seen by American pilots behind enemy lines during World War II, according to a statement by the archaeology company Search, which was also involved in the discovery. Other participants included the nonprofit Air/Sea Heritage Foundation, the National Oceanic and Atmospheric Administration's (NOAA) Maritime Heritage program and the U.S. Navy.

The mystery was solved only after the end of the war, when the vessel was found afloat in the Japanese port city of Kure, near Hiroshima.

The wreck is in remarkably good shape after nearly 80 years under the sea, according to the statement, and will give insight into early-20th-century naval architecture and technology.

"The USS Stewart represents a unique opportunity to study a well-preserved example of early twentieth-century destroyer design," maritime archaeologist James Delgado, who was formerly with NOAA and is now a senior vice president at Search, said in the statement.

"Its story, from U.S. Navy service to Japanese capture and back again, makes it a powerful symbol of the Pacific War's complexity," he said.

Editor's note: This story was updated at 1:43 p.m. EDT on Oct. 7 to note that the destroyer USS Stewart was not the only warship that fought for both the U.S. and Japan during World War II.

Four texts that discuss how the samurai carried out Seppuku, a ritual death in which a fellow samurai would usually behead another, have been translated into English for the first time. While the popular imagination often has the samurai stabbing themselves in the stomach and taking their own lives, this rarely happened during the Edo period (1603 to 1868).

The earliest of the four translated texts, named "The Inner Secrets of Seppuku," dates to the 17th century. "This document contains secret teachings that are traditionally only taught verbally, however they have been recorded here so that these lessons will not be forgotten and Samurai can be prepared," wrote Mizushima Yukinari, a samurai who lived between 1607 and 1697, a time when a shogun effectively ruled Japan. While the emperor was technically the ruler of Japan, the shogun held actual political control of the country. During the Edo period, the shoguns were descended from Tokugawa Ieyasu, a warlord who rose to power in Japan and became shogun in 1603.

The texts were translated into English by Eric Shahan, a Japanese translator who specializes in translating martial arts texts and published in the book "Kaishaku: The Role of the Second" (self published, 2024). Shahan also holds a San Dan (third-degree black belt) in Kobudo and has translated many Japanese martial arts texts. In the introduction, Shahan notes that the word "kaishaku" or "second" is a person charged with assisting in the ceremony, and often performed the beheading. The four texts were written to help give instructions to the kaishaku.

The texts described the ceremony, showing how it varied depending on a samurai's rank and which crimes, if any, they were considered to be guilty of. The texts note that it was vitally important that those carrying out the beheading do so correctly, noting that one error in particular could bring about great shame.

"It is essential that you do not fail to notice first the eyes and then the feet of the person committing Seppuku," or the person about to die, reads one of the texts called the "Secret Traditions of Seppuku," written in 1840 by a samurai named Kudo Yukihiro. "If you fail to do this due to a personal connection with the condemned, it will be proof that you have lost your martial bearing and bring down an eternal shame upon yourself."

Related: 7.5-foot-long sword from 4th-century Japan may have 'protected' deceased from evil spirits

While the ceremony varied tremendously, many versions of it involve giving sake (rice wine) to the condemned before a knife was brought on a plate. While the condemned could plunge the knife into themselves, this was often not done. Instead, the texts indicate that the kaishaku would often cut off the condemned person's head shortly after the knife was brought out, Shahan told Live Science in an email.

Shahan noted that the Edo period, the time when two of the texts were written, was one of relative peace in Japan and samurai were not always as skilled with knives and daggers as they had been in earlier times.

In earlier times, when samurai did cut open their own stomachs during Seppuku, they did so in an elaborate way that involved "cutting across the belly, from left to right then, pulling the knife out, repositioning it above the solar plexus and then cutting straight down to make a cross shape before removing the knife and placing it on your right knee," Shahan said. The lower level of skill that samurai tended to have in the Edo period made it difficult for them to perform this properly.

Ranking

A person's rank often dictated how the ceremony was conducted. If the condemned included lords and high-ranking samurai, they would be given the highest level of treatment. A samurai who chose to take their own life when their lord died would also be given the highest level of treatment. People at the highest level would be given some discretion as to how they wanted the ceremony carried out and those conducting it were often of the highest rank and wore a new kamishimo, a formal outfit worn by samurai.

The decapitated heads of high-ranking samurai were likely also treated better after death than those of lower-level warriors. The text written by Yukihiro describes how, at least for high level executions, the hair of the decapitated head should be perfumed afterward and wrapped in a white square cloth before being placed in a box.

Those samurai who were of low rank and considered to have committed the most severe crimes could be given "yondan" — fourth level treatment. This consisted of the condemned being bound and having their head cut off before being tossed into a hole.

While the texts say that a high-ranking samurai should be given better treatment during Seppuku, this may not always have happened.

"The highest-ranking person to commit Seppuku is probably Oda Nobunaga, who committed Seppuku in 1582, after his retainer Akechi Mitsuhide betrayed him and attacked him at Honnoji Temple" in Kyoto, Shahan said.

"Oda was a Daimyo, or lord of one of the hundreds of domains ruled by a powerful Samurai. He had been slowly eliminating his opponents and had succeeded in unifying Japan under his rule when he was betrayed," Shahan said. He chose Seppuku, but "due to the extreme circumstances — he was woefully outmatched, and being overrun — it is unclear how his Seppuku ceremony was conducted," Shahan said. So he may not have had the chance to arrange for an orderly ceremony that included drinking sake or having his hair perfumed after death.

From the swimming habits of dead trout to the revelation that some mammals can breathe through their backsides, a group of leading leftfield scientists have been taking their bows at the Massachusetts Institute of Technology for the 34th annual Ig Nobel Prize ceremony. Not to be confused with the actual Nobel prizes, the Ig Nobels recognise scientific discoveries that “make people laugh, then think."

We caught up with one of this year’s winners, Saul Justin Newman, a senior research fellow at the University College London Centre for Longitudinal Studies. His research finds that most of the claims about people living over 105 are wrong.

How did you find out about your award?

I picked up the phone after slogging through traffic and rain to a bloke from Cambridge in the UK. He told me about this prize and the first thing I thought of was the lady who collected snot off of whales and the levitating frog. I said, "absolutely I want to be in this club."

What was the ceremony like?

The ceremony was wonderful. It’s a bit of fun in a big fancy hall. It's like you take the most serious ceremony possible and make fun of every aspect of it.

But your work is actually incredibly serious?

I started getting interested in this topic when I debunked a couple of papers in Nature and Science about extreme ageing in the 2010s. In general, the claims about how long people are living mostly don't stack up. I've tracked down 80% of the people aged over 110 in the world (the other 20% are from countries you can't meaningfully analyze). Of those, almost none have a birth certificate. In the US there are over 500 of these people; seven have a birth certificate. Even worse, only about 10% have a death certificate.

The epitome of this is blue zones, which are regions where people supposedly reach age 100 at a remarkable rate. For almost 20 years, they have been marketed to the public. They’re the subject of tons of scientific work, a popular Netflix documentary, tons of cookbooks about things like the Mediterranean diet, and so on.

Related: Does the Mediterranean diet reduce dementia risk? 20-year study hints no

Okinawa in Japan is one of these zones. There was a Japanese government review in 2010, which found that 82% of the people aged over 100 in Japan turned out to be dead. The secret to living to 110 was, don't register your death.

The Japanese government has run one of the largest nutritional surveys in the world, dating back to 1975. From then until now, Okinawa has had the worst health in Japan. They've eaten the least vegetables; they've been extremely heavy drinkers.

What about other places?

The same goes for all the other blue zones. Eurostat keeps track of life expectancy in Sardinia, the Italian blue zone, and Ikaria in Greece. When the agency first started keeping records in 1990, Sardinia had the 51st highest old-age life expectancy in Europe out of 128 regions, and Ikaria was 109th. It's amazing the cognitive dissonance going on. With the Greeks, by my estimates at least 72% of centenarians were dead, missing or essentially pension-fraud cases.

What do you think explains most of the faulty data?

It varies. In Okinawa, the best predictor of where the centenarians are is where the halls of records were bombed by the Americans during the war. That's for two reasons. If the person dies, they stay on the books of some other national registry, which hasn’t confirmed their death. Or if they live, they go to an occupying government that doesn't speak their language, works on a different calendar and screws up their age.

According to the Greek minister that hands out the pensions, over 9,000 people over the age of 100 are dead and collecting a pension at the same time. In Italy, some 30,000 "living" pension recipients were found to be dead in 1997.

Regions where people most often reach 100 to 110 years old are the ones where there's the most pressure to commit pension fraud, and they also have the worst records. For example, the best place to reach 105 in England is Tower Hamlets. It has more 105-year-olds than all of the rich places in England put together. It's closely followed by downtown Manchester, Liverpool and Hull. Yet these places have the lowest frequency of 90-year-olds and are rated by the UK as the worst places to be an old person.

The oldest man in the world, John Tinniswood, supposedly aged 112, is from a very rough part of Liverpool. The easiest explanation is that someone has written down his age wrong at some point.

But most people don’t lose count of their age…

You would be amazed. Looking at the UK Biobank data, even people in mid-life routinely don't remember how old they are, or how old they were when they had their children. There are similar stats from the US.

What does this all mean for human longevity?

The question is so obscured by fraud and error and wishful thinking that we just do not know. The clear way out of this is to involve physicists to develop a measure of human age that doesn't depend on documents. We can then use that to build metrics that help us measure human ages.

Longevity data are used for projections of future lifespans, and those are used to set everyone’s pension rate. You're talking about trillions of dollars of pension money. If the data is junk then so are those projections. It also means we're allocating the wrong amounts of money to plan hospitals to take care of old people in the future. Your insurance premiums are based on this stuff.

What’s your best guess about true human longevity?

Longevity is very likely tied to wealth. Rich people do lots of exercise, have low stress and eat well. I just put out a preprint analysing the last 72 years of UN data on mortality. The places consistently reaching 100 at the highest rates according to the UN are Thailand, Malawi, Western Sahara (which doesn't have a government) and Puerto Rico, where birth certificates were cancelled completely as a legal document in 2010 because they were so full of pension fraud. This data is just rotten from the inside out.

Do you think the Ig Nobel will get your science taken more seriously?

I hope so. But even if not, at least the general public will laugh and think about it, even if the scientific community is still a bit prickly and defensive. If they don't acknowledge their errors in my lifetime, I guess I’ll just get someone to pretend I’m still alive until that changes.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Japan has announced plans to start constructing the first ever "zeta-class" supercomputer next year. Once fully operational, it will be 1,000 times faster than today's most powerful supercomputers.

The supercharged machine, which could cost more than $750 million to build, will help Japan keep up with the pace of artificial intelligence (AI) development and is expected to be fully online by 2030.

Plans for the new machine — first released on Aug. 28 by Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT) — reveal that the supercomputer could reach speeds on a zetaFLOPS scale, which has never been achieved before.

Floating-point operations per second (FLOPS) is used to measure how fast computers can solve problems — where one floating-point operation is a single calculation. A supercomputer with a speed of 1 zetaFLOPS could make one sextillion (1 followed by 21 zeros) calculations per second. Today's most powerful supercomputers have only just broken the exaFLOPS barrier, meaning they can make just over one quintillion (1 followed by 18 zeros) calculations per second.

The decision to build such a superpowered machine has been made "in order to keep up with the development of scientific research using AI," Japanese news site Nikkei wrote in a translated article.

Related: Computer inspired by Japanese art of paper-cutting has no electronics and stores data in tiny cubes

The proposed supercomputer is being touted as the successor to Japan's Fugaku supercomputer (0.44 exaFLOPS), which previously held the title of the world's fastest supercomputer until it was dethroned in 2022 by the U.S.'s Frontier supercomputer (1.2 exaFLOPS) at Oak Ridge National Laboratory in Tennessee. Fugaku is currently considered to be the fourth most powerful supercomputer in the world.

The new machine, which is currently being referred to as "Fugaku Next," will be built by Japanese companies RIKEN and Fujitsu, which were both involved in the construction of Fugaku. To allow cross-compatibility between Fugaku and Fugaku Next, the latter will likely use components designed by Fujitsu, according to computing news site Tom's Hardware. However, little else is known about the components that will be fitted into the proposed machine.

One of the biggest challenges engineers will face in building the new supercomputer is finding a way to make it run efficiently. In 2023, computer experts predicted that a zeta-class machine built using current supercomputer technologies would require the equivalent energy to the output of 21 nuclear power plants, computing news website HPCwire previously reported.

MEXT has set aside around ¥4.2 billion ($29 million) for the first year of the project but could allocate up to ¥110 billion ($761 million) throughout the project, which is scheduled to be completed by 2030, according to Tom's Hardware.

As long as construction goes to plan and nobody else builds a zeta-class machine first (which seems highly unlikely), then Fugaku Next will likely be the most powerful supercomputer on Earth.

A dolphin attacking swimmers in Japan is probably lonely and sexually frustrated, experts say.

At least 18 people have been injured in dolphin attacks in Fukui prefecture this year in what is becoming an annual occurrence in the region. Most of the injuries are minor bites, but some beachgoers have suffered broken bones since the attacks started in 2022.

Researchers believe a lone male Indo-Pacific bottlenose dolphin (Tursiops aduncus) is likely responsible for the attacks based on photographs and video footage, Nature reported.

"We've seen that this dolphin randomly shows up at a beach, bites if there are people around, wanders off and repeats," Tadamichi Morisaka, a professor in the Cetacean Research Center at Mie University in Japan, told Nature. "To me, he's seeking some kind of interaction with people."

Dolphins engage in gentle biting with each other as part of their normal social behavior, so the dolphin might believe he's got a friendly relationship with the humans, Morisaka said.

"If he really wanted to attack, he could have come tackling at full force and chomped down. But he's keeping the biting gentle for dolphin standards, so it's probably a friendly gesture rather than a full-on attempt to attack," he said.

Related: Dolphins are 'literally acting like jerks' by beating up baby manatees

It's unclear why the dolphin is on his own. Bottlenose dolphins usually live in pods, with males forming long-term partnerships with other males. Paired males bite, chase, rub and engage in sexual behaviors such as pressing their penises against one another as part of these relationships, and Morisaka believes the dolphin in Fukui is trying to treat humans like a male pair mate.

Ryoichi Matsubara, the director of Echizen Matsushima Aquarium in Fukui, told The New York Times that the dolphin was observed trying to press his genitals against people in 2022 and 2023, and that he might be acting out mating behavior — but also biting beachgoers if they approached or tried to touch him.

Other researchers have also suggested that the attacks could partly be the result of the dolphin's desire to mate. Simon Allen, a principal investigator at the Shark Bay Dolphin Research project in Western Australia, told BBC News that dolphins can express their sociality in physical ways.

"Just as in humans and other social animals, hormonal fluctuations, sexual frustration or the desire to dominate might drive the dolphin to injuring the people it interacts with," Allen said. "Since they are such powerful animals, this can lead to serious injury in humans."

Fukui prefecture authorities are discouraging people from interacting with the dolphin. They've put up signs and fliers warning beachgoers, introduced lifeguard patrols and are limiting swimming hours on certain beaches, the Times reported. Authorities have also installed underwater acoustic devices emitting high-frequency noises to deter dolphins.

However, Morisaka is concerned the dolphin could get used to the acoustic devices and instead wants to develop an echolocation detection system to alert beachgoers that a dolphin is nearby. He believes that with people out of the water, the dolphin won't find anything interesting at the beaches and will eventually leave them alone.

If the human-dolphin interactions continue, they could become more dangerous. Morisaka said dolphins can begin attempting to assert their dominance over humans, engaging in aggressive behaviors such as tackling or mounting.

"We saw a bit of this last summer, so I was very concerned," Morisaka said. "They are about 2.5 metres [8.2 feet] long and weigh around 200 kilograms [440 pounds], so if they came charging at 20-30 kilometres per hour [12 to 19 mph], it'd be like getting into a traffic accident."

Japan's commercial whaling activities could soon expand to include fin whales, government officials announced last week.

The move, which experts have heavily condemned, would increase the number of whale species Japan hunts in its territorial waters to four; the other three species are the Bryde's whale (Balaenoptera edeni), the sei whale (Balaenoptera borealis) and the minke whale (Balaenoptera acutorostrata). 

For now, it appears the decision to include fin whales hinges on public approval of changes to the country's marine resource management policy, according to the marine conservation organization OceanCare. 

The fin whale (Balaenoptera physalus) is the second-largest whale species on Earth, after the blue whale (Balaenoptera musculus). Fin whales are named for the distinctive fin that protrudes from their lower back, and they can grow up to 85 feet (26 meters) long. They are found across all the world's oceans. In the first half of the 20th century, however, fin whale populations nose-dived due to commercial whaling and they are still recovering from the shock, according to the International Whaling Commission (IWC), which regulates modern whaling practices.

In 1982, the IWC introduced a moratorium on commercial whaling that went into effect in 1986. Although Japan stopped commercial hunts after 1986, the country resumed taking whales for what it said was scientific research one year later. In 2019, Japan withdrew from the IWC and began catching whales commercially once again, although its whaling activities are now restricted to the country's territorial waters in the North Pacific Ocean.

Related: Hidden DNA found in blue whales reveals they've been mating with other species — and their hybrid offspring

On May 9, officials announced that Japan could start hunting fin whales soon. "Whales are important food resources and should be sustainably utilized, based on scientific evidence," Yoshimasa Hayashi, Japan's minister for foreign affairs, said at a news conference.

According to the IWC's most recently published whaling data, Japan took 25 sei whales, 187 Bryde's whales and 58 minke whales in 2022. In recent years, the country has also imported fin-whale meat from Iceland, according to OceanCare. 

The International Union for Conservation of Nature (IUCN) lists fin whales as vulnerable to extinction globally, although the species was still listed as endangered as recently as 2018 and is considered as such under the Endangered Species Act of 1973. However, there is insufficient data to pinpoint the status of local populations in the North Pacific, according to the IWC. 

Without reliable population estimates, Japan's move to hunt fin whales is an "appalling step backward" for ocean protection, Clare Perry, a senior adviser at the Environmental Investigation Agency (an international NGO that investigates environmental crime and abuse), said in a statement. 

"Fin whales are one of Earth's great carbon capturers and should be fully protected, not least so that they can continue to fulfill their critical role in the marine environment," Perry said.

The announcement comes after Japan unveiled a brand-new whaling "mother ship" in March. The factory ship, called the Kangei Maru, can handle and process large whales, including fin whales, "which could tie Japan into decades more of this destructive, unsustainable, inhumane and outdated industry," Perry said.

Whether or not Japan goes ahead with its plans to hunt fin whales depends on the outcome of a public consultation of the country's newly drafted whaling policy — but it seems likely the changes will be approved, according to OceanCare.

A private Japanese company has taken the world's first close-up photo of an individual piece of space debris, by parking another satellite next to it in orbit. This orbital photo op is the first step in an ongoing mission to capture and destroy potentially hazardous pieces of space junk that are clogging up our sky. 

It's easy to imagine space as a vast, empty frontier. But since the first satellite launched in 1957, the space surrounding our planet has gotten more and more crowded. Human-made space junk — including used rocket stages, decommissioned satellites, frozen fuel and flecks of paint — has been steadily accumulating in Earth's orbit over the past seven or so decades. Now, the space industry is trying to find ways to remove it.

There is currently more than 9,900 tons (9,000 metric tons) of space junk hanging out in Earth's orbit. That debris is a veritable minefield for newly launched satellites and spacecraft; even a tiny piece of debris can tear a hole through a spacecraft with enough momentum. It can even pose a threat to people on the ground when it falls from orbit. And the longer that space debris stays in orbit, the more it multiplies. Collisions between defunct satellites or parts of rockets can break larger debris into smaller pieces, making the resulting fragments harder to track and increasing their chances of hitting an active satellite.

Understandably, space agencies around the world are interested in cleaning up some of that floating garbage before it damages functioning spacecraft. A private Japanese company recently took some of the first steps. 

Related: Sci-fi inspired tractor beams are real, and could solve a major space junk problem

In mid-April, a spacecraft launched by private space company Astroscale successfully identified, approached and photographed a large piece of orbital debris — the upper stage of a Japanese H-IIA rocket that has been circling Earth since 2009. The demonstration was meant to test the craft's ability to maneuver close enough to a piece of space junk to capture it, without crashing into it. By all accounts, the mission was a success, setting the stage for future removal missions. 

This milestone earned Astroscale a partnership with the Japan Aerospace Exploration Agency's (JAXA) Commercial Removal of Debris Demonstration initiative. The company is currently planning the second phase of the mission, which aims to remove a piece of debris, using a robotic arm attached to the craft to push the debris into a fiery descent through Earth's atmosphere.

JAXA is not the only space agency looking to clean up Earth's orbit. The European Space Agency (ESA) has an active space-debris removal mission called ClearSpace-1, which is scheduled for launch in 2025. NASA is currently developing its own debris-removal program in partnership with six private U.S. space companies. And Astroscale's U.K. branch plans to launch a cleanup mission later next year. 

Modern Japanese people largely descend from three ancestral groups, a new study suggests. The research also reveals genetic ties with our closest extinct relatives — the Neanderthals and Denisovans — and how these genes may affect present-day disease risk. 

In one of the largest non-European analyses of its kind, scientists sequenced the DNA of more than 3,200 Japanese people across seven regions of the country, extending from the snowy mountains of Hokkaido in the north to the subtropical southern shores of Okinawa. 

The researchers collated these genetic data, along with relevant clinical information, into a large new database called the Japanese Encyclopedia of Whole-Genome/Exome Sequencing Library (JEWEL).

The team discovered that modern Japanese people mostly descended from three ancestral groups: Neolithic Jomon hunter-gatherers; a group believed to have been the ancient predecessors of the Han Chinese; and an unidentified group with ties to Northeast Asia. This finding further challenges a contested, three-decades-long hypothesis that Japanese people originated from the Jomon people and, later, rice-farming Yayoi migrants from continental Asia.

Related: India's evolutionary past tied to huge migration 50,000 years ago and to now-extinct human relatives

The new analysis also revealed 42 pieces of DNA that Japanese people inherited from Neanderthals and two from Denisovans that could be linked to complex traits, meaning those that are encoded by multiple genes. This inheritance was likely the result of earlier interbreeding events between these ancient groups and early Homo sapiens, the authors wrote in the paper. 

Denisovan-derived DNA within a gene called NKX6-1 was associated with the development of type 2 diabetes (T2D), and within the gene POLR3E, it was tied to height, the authors found. Eleven Neanderthal-derived DNA sequences were found to be associated with seven diseases, including T2D, coronary artery disease, prostate cancer and the inflammatory disorder rheumatoid arthritis. Most of these 44 chunks of ancient DNA are unique to East Asians, the authors said. 

Until recently, large-scale genetic sequencing research has focused on analyzing DNA from people of European descent, leaving a significant gap in our understanding of other human populations, including those in Asia. Therefore, the new findings may provide some long-coveted answers.

"This comprehensive genetic dataset enables us to delve into uncharted territories concerning population and medical genetics of the Japanese population," the authors wrote in a paper describing their findings, published Wednesday (April 17) in the journal Science Advances. 

These discoveries could even supplement research that could lead to the development of personalized medicine, the authors wrote. 

For instance, the team identified gene mutations that could be clinically important within the Japanese population. One notable example is a mutation in a gene called PTPRD that was found in six people in the cohort. Clinical information was available for three of these individuals, who experienced several of the same health conditions, including having heart attacks, kidney failure and high blood pressure. 

JEWEL will serve as a "reference for future genetic research within and beyond the Japanese population," the study authors concluded.

Name: Skeleton panda sea squirt (Clavelina ossipandae)

Where it lives: Off the coast of Kumejima, Japan

What it eats: Plankton and other small organic materials

Why it's awesome: Resembling a baby panda in a Halloween costume, this adorable species of ascidians, or sea squirts, was first described by scientists in 2024.

"The white parts that look like bones are the blood vessels that run horizontally through the sea squirts' gills. The black parts on the head that look like a panda's eyes and nose are just a pattern, and we don't really know why the pattern is there," Naohiro Hasegawa, a researcher at Hokkaido University and co-author of the study that first described the species in the journal Species Diversity, told Reuters.

Related: Barreleye fish — the deep-sea weirdo with rotating eyes and a see-through head

Photos of these unusual animals first appeared online in around 2017. Researchers saw photos posted by a diving center and realized they might be something scientists had never seen before. The researchers then analyzed specimens collected by divers and confirmed it was a never-before-described species. 

The researchers who described the strange animals called them "gaikotsu-panda-hoya, "which translates to "skeleton panda ascidian" because of the distinctive markings that make them look like a bony body with a panda's face and wide-open mouth.

The scientific name of this odd species also refers to its appearance: in Latin, Clavelina means "little bottle" while ossipandae comes from "os" meaning bones, and panda.

Other sea squirts bear similar markings: C. moluccensis — also known as the bluebell sea squirt — has skeletal stripes and dark blue dots on its pale blue body while c. picta — the painted sea squirt — has similar spots and rib-like stripes.

Like other sea squirts, skeleton pandas are filter-feeding marine invertebrates that attach themselves to the substrate and pump water through their siphons to filter nutrients from the water. They grow less than an inch long (20 millimeters) and are found in shallow waters of up to 66 feet (20 meters). 

SLIM's not dead yet.

The SLIM spacecraft, Japan's first-ever successful moon lander, has survived the long, cold lunar night for the second time.

Mission team members announced the news via X on Wednesday (March 27), in a post that also featured a photo newly snapped by the lander's navigation camera.

SLIM, whose name is short for "Smart Lander for Investigating Moon," launched last September and landed on Jan. 19, making Japan just the fifth nation to pull off a soft lunar touchdown. (The other four are the Soviet Union, the United States, China and India.)

Related: 'Everything has changed since Apollo': Why landing on the moon is still incredibly difficult in 2024

The solar-powered SLIM landed on its nose that day, a less-than-optimal orientation for harvesting sunlight. The 440-pound (200 kilograms) probe went dark shortly thereafter but then woke up on Jan. 28 and began gathering data.

The mission team put SLIM into hibernation a few days later ahead of the two-week-long lunar night, during which surface temperatures at its locale dropped to around minus 208 degrees Fahrenheit (minus 130 degrees Celsius).

SLIM had already achieved its primary mission goals — making a precision touchdown, deploying two tiny rovers and conducting a variety of science work — by that point and was not expected to open its eyes again. But the probe did so, waking up late last month.

SLIM now has a second revival under its belt, though the extreme conditions are beginning to take their toll on the plucky little robot.

"According to the acquired data, some temperature sensors and unused battery cells are starting to malfunction, but the majority of functions that survived the first lunar night was ma[i]ntained even after the second lunar night!" mission team members said in another X post on Wednesday night.

SLIM's January touchdown was followed a month later by that of Odysseus, which was built and operated by Houston-based company Intuitive Machines. Odysseus' lunar touchdown was the first ever by a private spacecraft and the first for an American vehicle since Apollo 17 in 1972.

Odysseus operated for a week on the lunar surface, then went silent ahead of its first lunar night. And that silence is forever; Intuitive Machines announced earlier this week that Odysseus' mission is over.

Originally posted on Space.com.

Scientists have identified the largest volcanic eruption in recorded history — an explosion 7,300 years ago that ejected more than twice as much rock and ash as the previous record-holding eruption of Indonesia's Mount Tambora in 1815.

The earth-shattering blast, known as the Kikai-Akahoya eruption, occurred south of Japan's Kyushu island, where the Philippine tectonic plate slips beneath the Eurasian plate. The underwater Kikai volcano is known to have produced three major eruptions in the last 140,000 years, the latest of which was the Kikai-Akahoya eruption, according to a study published online Feb. 1 in the Journal of Volcanology and Geothermal Research.

While scientists already knew about the ancient volcanic blast, the new research has revealed its record scale and pinpointed it as the largest eruption of the current geological epoch. "The eruption has been known for a long time, but these authors are increasing our knowledge of it a lot," Tim Druitt, a professor of volcanology at the University of Clermont Auvergne in France who reviewed the study, told Live Science in an email. 

Scientists had previously found it difficult to pin down the eruption's size and what triggered it because of the inherent challenge in accessing the underwater volcano.

In the new study, researchers gathered seismic data to create a detailed map of the seabed around the volcano. The map revealed vast underwater deposits, which the team sampled by drilling into the seabed in several locations with a remote-controlled robot and extracting sediment cores. 

Related: Underwater Santorini volcano eruption 520,000 years ago was 15 times bigger than record-breaking Tonga eruption

The sediment hauled to the surface revealed a layer spanning 1,740 square miles (4,500 square kilometers) that contained volcanic glass matching the composition and timing of the Kikai-Akahoya eruption. The glass and other volcanic debris amounted to roughly 17 cubic miles (71 cubic kilometers) of material ejected into the sea by the eruption — almost double the estimates published in previous research.

The researchers combined these findings with existing estimates of volcanic debris from the eruption that was deposited on land. They found that the mega eruption expelled a total volume of 80 to 110 cubic miles (332 to 457 cubic km) of material — enough to fill Lake Tahoe in the western U.S. twice over. 

The new estimate means the Kikai-Akahoya eruption is "probably the largest eruption of the Holocene," the researchers wrote in the study. The Holocene Epoch is a geological period that began 12,000 to 11,500 years ago at the end of the last ice age and which we still live in today.

"Their conclusion that it is the largest Holocene eruption is valid," Druitt said. "The Minoan eruption of Santorini has also been proposed as the largest Holocene eruption, but is now known not to be."

The Kikai-Akahoya eruption still pales in comparison to more ancient eruptions, such as the cataclysmic explosion of Sumatra's Toba supervolcano 74,000 years ago, which pumped out an estimated 1,200 cubic miles (5,000 cubic km) of magma. 

On Thursday (Feb. 22), a phone booth-sized spacecraft named Odysseus made history. Landing at the moon’s south pole at 6:23 p.m. ET, Odysseus — built by the Houston-based company Intuitive Machines — became the first U.S. lander to touch down on the moon in more than 50 years, and the first private lander to ever reach the lunar surface.

But this successful landing was far from flawless. Several days after touchdown, it became clear that Odysseus broke one of its six legs upon landing, and had ended up toppled on its side. With limited power reaching the lander's solar cells, engineers powered it down, potentially for good, on Feb. 29.

Odysseus' challenges add to a trend of troubled lunar landings, with five of the previous nine attempted moon landings ending poorly for various nations and private companies.

Weeks earlier, on Jan. 19, Japan's Smart Lander for Investigating the Moon (SLIM) spacecraft successfully completed the country's first moon landing — albeit ending up upside down on the lunar surface due to an engine malfunction during descent. The lopsided lander's solar cells faced the wrong direction and failed to power its instruments and communications, forcing engineers to shut it down in fear of battery discharge. Just 10 days prior to SLIM's landing, a private U.S. moon lander named Peregrine encountered many anomalies after launch, including a propellant leak that prevented the spacecraft from landing on the moon. It was ultimately rerouted to crash into Earth's atmosphere. Other lunar landing attempts made by Japan and Russia in 2023 similarly ended in catastrophic crashes, this time on the moon itself.

Government-funded space agencies of only five countries have successfully touched down on the moon: the United States, the former Soviet Union, China, India and Japan. Just one private company (Intuitive Machines) has succeeded so far, and several high-profile missions have failed due to technical glitches that led to fatal judgments of speed, altitude and orientation — a stark reminder that even after half a century since the Apollo astronauts walked on the moon, our closest celestial neighbor remains a challenging and dangerous destination.

So, what gives? Has humanity gotten worse at lunar landings? Or are we simply grappling with a new era of technological advancements, just like the teams behind the Apollo missions did?

"We did not get 'dumber' since the Apollo landings," Csaba Palotai, a professor of physics and space sciences at the Florida Institute of Technology in Melbourne, told Live Science. Technology is significantly better today; your cellphone has more computational power than computers had in the 1970s. "But since the '70s there have been no astronauts and pilots on the landers to correct what the computers can't or won't," Palotai added.

Acing the technology (again)

Landing on the moon is hard, with or without human pilots.

A major hurdle is the moon's virtual lack of atmosphere. The lunar atmosphere is very thin and varies with time, preventing engineers from including parachutes to slow down spacecraft, Palotai said. Instead, missions use fuel-powered propulsion systems to descend onto the moon's surface, making it challenging to slow the spacecraft from a few kilometers per second to a perfect halt.

Yet this and other lunar exploration challenges are not new.

While the Apollo program was ultimately successful in landing humans on the moon, it was the culmination of a large program that failed many times on its way to success. Early attempts by the U.S. and the Soviet Union to fly a spacecraft to the moon were riddled with failures, including post-launch explosions, malfunctions with guidance systems, and fatal errors with solar panel deployment. Even the historic Apollo 11 mission, which landed astronauts Neil Armstrong and Buzz Aldrin on the moon, was worryingly low on fuel and faced multiple unexpected alarms just before landing on the moon.

"People tend to forget about those mission failures as being part of the learning process," said Jack Burns, director of the NASA-funded Network for Exploration and Space Science at the University of Colorado Boulder. This experiential learning perch is where moon missions, especially a growing number of privately funded ones, currently are. "It's still hard to land on the moon, but far from impossible," he said.

Burns and other experts agree that just about everything has changed since the Apollo program, including the now-antiquated technology that took humans to the moon and back in the '60s and '70s. Engineers with the Apollo program had built the first computers of their time, including sensors that have since been made more powerful in a fraction of their original sizes. Much of the software and architecture customized for the Apollo program is effectively useless for space missions today.

Moreover, "that whole generation is out of the industry at this point, and a lot of that knowledge has been lost," said John Thornton, CEO of Pittsburgh-based Astrobotic Technology, which built and operated Peregrine. "We are relearning how to do this, but we're also learning it with technology that is new and different."

Half a century after humans last walked on the moon, organizations smaller than NASA — powered by a new generation of engineers — have taken on the same challenge that only governments accomplished in the past. Palotai, Thornton and Burns view the recent moon mission failures as the natural progression of a new industry.

"Personally, I'm not worried," Burns said. "It's just part of the growing pains."

Paving the way for affordable moon missions

While technological issues influence the outcome of a mission, funding determines the extent of the software and hardware testing done in advance of launch to reduce risk.

"If we had a billion dollars to do this mission, our chances of success would go way up," Thornton said of the doomed Peregrine, whose mission failure investigation is expected to take a month or two. "But we're trying to do this at a much lower cost, which means you have to try many more times before you get to that breakthrough moment of, 'OK, now we know exactly how to do it at this price point. Let's keep doing it again and again.'"

Back in the '60s and '70s, in the heat of the space race between the U.S. and the Soviet Union, the Apollo program was the crux of NASA's work, and the space agency had 10 times its current budget to do the same thing. Between 1960 and 1973, NASA spent $25.8 billion ($257 billion when adjusted for inflation) on the Apollo program and was backed by nearly 5% of the total U.S. federal budget.

Comparatively, NASA now receives less than 0.5% of the nation's overall federal spending, and that budget also funds missions to destinations beyond the moon.

"That changes everything," Thornton said. Back then, NASA was fine with developing something that cost tens of billions of dollars. In comparison, today the industry is trying to build spacecraft for about $100 million, an affordable price that's key to routine flights. This problem is fundamentally different from those of the Apollo era. "It's going to take time to learn how to do it at that price point," Thornton said.

Lowering mission costs also increases the risk of failure, at least to start, Martin Barstow, a professor of astrophysics and space science at the University of Leicester in the U.K., told Live Science. So "we shouldn't be too surprised if some of these things don't work," Barstow added.

The first commercial victory

The Odysseus spacecraft’s successful landing on Feb. 22 marked a welcome breakthrough for the commercial spaceflight industry.

The lander (nicknamed "Odie") delivered 12 payloads to the moon, including six NASA science instruments. For these, the space agency paid Intuitive Machines $118 million through its Commercial Lunar Payload Services program (CLPS), designed to award private companies contracts to send experiments to the moon rather than NASA doing it itself. (NASA moon missions can cost up to $1 billion each.)

As part of the same CLPS program, Astrobotic plans to launch its second robotic moon lander, Griffin, and a water-hunting rover this November.

Editor's note: This article was updated on March 1 to add new information about the Odysseus lander's mission.

A strange,never-before-seen jellyfish with a distinctive stomach that looks like a red cross has been discovered inside a volcanic structure off the coast of Japan.

Researchers spotted the jellyfish, which has been named the St. George's cross medusa (Santjordia pagesi), 2,664 feet (812 meters) below the Pacific Ocean's surface near Japan's Ogasawara Islands. It was floating around the Sumisu caldera, a 6.2-mile-wide (10 kilometers) hydrothermally active volcano that sits on a volcanic arc, or chain of volcanoes, known as the Ring of Fire.

The umbrella-shaped jellyfish has a diameter of around 4 inches (10 centimeters) and is transparent, except for a bright red cross, which is visible when the creature is viewed from above.

The jellyfish is so rare it has only ever been spotted twice. It was first seen in 2002 by a remotely operated vehicle (ROV) during a dive in the Sumisu caldera. However, researchers could not describe a newfound species based on a single specimen, as it could have been a mutated individual belonging to an already-known species, according to a statement from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC).

Related: City-size seamount triple the height of world's tallest building discovered via gravitational anomalies

In 2020, scientists revisited the region and spotted the mysterious jellyfish again. While they were unable to collect a sample, they filmed the jellyfish swimming around.

This second encounter enabled them to describe the jellyfish as a unique species. The team reported its findings in a study published Nov. 20, 2023, in the journal Zootaxa.

The unusual cross shape at the center of S. pagesi is the jellyfish's stomach. The color helps to disguise the jellyfish and the food it consumes from predators in its dark, deep-sea home. Much of the creature's diet consists of bioluminescent organisms that glow in the dark — having a red stomach diminishes the light they emit, protecting the jellyfish from predators after it has eaten its meal.

S. pagesi differs a great deal to its closest relatives, which include large, deep-sea jellyfish such as Tiburonia granrojo and the giant phantom jelly Stygiomedusa gigantea, according to the statement. The newfound species is much smaller and, unlike its relatives, has tentacles as well as arms, which it uses for feeding. Because of its unusual traits, researchers believe S. pagesi may have a never-before-seen type of venom that could be used in genetic research, for example, in medicines.

The caldera where the jellyfish lives is rich in minerals and could potentially be commercially developed for deep-sea mining. The researchers published information about the jellyfish to try to protect the area and its marine life.

"Maybe it holds secrets more valuable than all the mineral wealth that could be extracted from that place. All this with the advantage of keeping the species and the site intact," André Morandini, a professor of zoology at the University of São Paulo's Institute of Biosciences and part of the research team, said in a statement.

Japan's historic SLIM moon lander has powered down ahead of a likely mission-ending cold lunar nighttime — but not before grabbing some final images and loads of science data. 

SLIM, short for "Smart Lander for Investigating Moon," nailed its precision touchdown on the rim of Shioli crater on Jan. 19, despite engine troubles that saw it land nose-down. As a result, the spacecraft's solar cells face westward and are unable to receive the expected levels of sunlight, initially cutting operations on the lunar surface very short. But SLIM triumphantly reawakened nearly 10 days after landing, as the sun finally shone on its panels.

The Japan Aerospace Exploration Agency (JAXA), which operates SLIM, has spent recent days scanning the nearby lunar surface with the spacecraft's Multi-Band Camera (MBC) to learn about its composition.

MBC is designed to scope out olivine and other minerals through analyzing the light signatures, or spectra, of reflected sunlight, according to the nonprofit Planetary Society.

JAXA's SLIM account on X, formerly Twitter, posted a final image taken by SLIM's navigation camera on Jan. 31 Japan time, while stating that the agency confirmed the spacecraft had entered a dormant state as expected.

JAXA will need to wait out the roughly 14.5-Earth-day-long lunar nighttime and then wait for favorable lighting and temperature conditions later in the next lunar daytime (which starts around Feb. 15) before SLIM can potentially be revived once more. For the probe to awake again, however, its electronics must hold up in the face of equatorial lunar nighttime temperatures of around minus 208 degrees Fahrenheit (minus 130 degrees Celsius).

But whether or not SLIM wakes up, the spacecraft has hit its full and extended mission goals by achieving a precision landing, deploying a pair of small rovers and demonstrating their interoperability, and obtaining a wealth of science data.

SLIM's X account also posted labeled images of targets of MBC's spectroscopic imaging, showing the various rocks and regolith that are being studied.

"Based on the large amount of data we have obtained, we are proceeding with analyses to identify rocks and estimate the chemical composition of minerals, which will help solve the mystery of the origin of the moon," a Google machine translation of a Feb. 1 JAXA statement read.

"We will announce scientific results as soon as they are obtained," the statement added.

Originally posted on Space.com.

Japan has re-established connection with its Smart Lander for Investigating the Moon (SLIM) spacecraft, almost nine days after it touched down on the moon's surface and lost power.

"Communication with SLIM was successfully established last night, and operations resumed!" the Japan Aerospace Exploration Agency (JAXA) posted on X, formerly known as Twitter, on Jan. 28 at around 7:30 p.m. ET.

On Jan. 19, the spacecraft was descending toward its landing spot near the rim of Shioli crater when one of its two main thrusters failed, causing SLIM to topple on its nose. As a result, SLIM's solar panels were initially at the wrong angle and unable to charge, but late on Sunday, the probe started to generate electricity, likely due to a change in the direction of sunlight, Reuters reported.

RELATED: Japan's 'Moon Sniper' lands on lunar surface, but it could be dead within hours

Nicknamed the "Moon Sniper," the spacecraft was designed using a new navigation system that enables precision landings, evidenced by SLIM's impressive accuracy when it touched down within 328 feet (100 meters) of its target despite its technological mishap — making Japan the fifth national space agency to land a spacecraft on the moon. During its descent, SLIM's navigational technology determined its location while cruising by comparing real-time images from its camera to satellite snapshots of the moon.

SLIM will now continue its mission to analyze the composition of olivine rocks — a common mineral in the lunar crust — using a multi-band spectral camera, which captures images beyond the wavelengths of light seen by the human eye. Before the spacecraft initially lost power, JAXA released images taken by the lander's camera of rocks in the surrounding area, then shared a new image of the "toy poodle" rock on the surface of the moon in its tweet last night.

While experts are not yet sure how long SLIM will remain operational, the agency has previously said that SLIM was not designed to survive a lunar night, the next of which begins on Feb. 1.

Japan successfully became the fifth nation to land on the moon on Friday (Jan. 19), when the country's robotic Smart Lander for Investigating the Moon (SLIM) successfully descended to the lunar surface at 10:20 a.m. EST (or 12:20 a.m. on Saturday, Jan. 20 in Japan).

The craft seems to have succeeded in making a soft landing on the moon, as SLIM is currently sending and receiving data from its new home near Shioli crater on the lunar near-side, mission officials said in a televised press conference on Friday. However, the lander may only survive for a few hours there following an error with the lander's solar energy cells, which are not generating electricity as expected, the officials said.

SLIM is currently running on reserve battery power, which will likely run out within a few hours. That gives researchers a limited time to carry out science operations with the lander before it goes offline. SLIM's solar cells may yet be able to generate electricity if the orientation of incoming sunlight changes and hits the panels in the coming weeks, the officials added. However, the lander's ultimate fate remains uncertain.

Despite this setback, Japan joins the United States, Russia, China and India as the only nations to successfully land a spacecraft on the moon.

Related: The Apollo moon landing was real, but NASA's quarantine procedure was not

SLIM — built by Japan's space agency (JAXA) and nicknamed the "Moon Sniper" — was designed to demonstrate a new navigation system capable of achieving pinpoint landings on the lunar surface. The mission's goal was to land the craft within a scant 330 feet (100 meters) of its target landing site, near the rim of Shioli crater, according to Live Science's sister site Space.com. It could take up to a month to verify how close the craft landed to its target, JAXA has said.

SLIM launched from Japan's Tanegashima Space Center in Minamitane on Sept. 6, 2023, and it reached a lunar orbit on Dec. 25. The craft spent the following weeks orbiting the moon and testing various systems before attempting its landing on Friday. 

SLIM, which measures about the size of a small truck, carried two robotic rovers with it, named Lunar Excursion Vehicle 1 and 2 (LEV-1 and LEV-2). The mission called for SLIM to deploy the two rovers during its attempted landing — and one of them (LEV-1) seems to be online.

This was not Japan's first attempted lunar landing. Last year, the private Japanese company ispace attempted to land its Hakuto-R lunar lander, but ground controllers lost contact with the craft during its descent on April 25, resulting in a crash landing. Earlier, in November 2022, a small lander named OMOTENASHI hitched a ride on NASA's uncrewed Artemis I mission. The tiny lander failed to survive its descent to the lunar surface, while the Artemis capsule continued its mission around the moon and then back to Earth.

Several recent lunar landing attempts made by other nations and private companies have also gone awry. 

On Jan. 8, the Peregrine lunar lander designed by U.S.-based space company Astrobotic Technology suffered a critical propellant leak just hours after launching, dooming the craft to burn up in Earth's atmosphere instead of completing its trip to the moon. And in August 2023, Russia's Luna 25 lander crashed into the moon's south pole during its attempted landing, leaving a new 33-foot-wide (10 m) crater behind.

Several weeks later, India's Chandrayaan-3 lander successfully landed at the lunar south pole, making India the first nation to land there, and the fourth to make a soft landing on the moon. However, the craft only remained operational for about a month before losing power. 

The lunar south pole is a popular target for future space missions, due largely to the abundance of frozen water locked up in permanently shadowed craters there.

Satellite images captured striking changes in the coastline of Japan's Noto Peninsula following a massive earthquake on New Year's Day.

A 7.6 magnitude earthquake struck Japan on Jan. 1 around 2:10 a.m. EST (0710 GMT, or 4:10 p.m. local time in Japan), prompting orders for residents to evacuate affected coastal areas that experienced significant uplift. Satellite imagery of the area before and after the quake shows that the intense uplift extended the coastline by up to 820 feet (250 meters), which is greater than the length of two American football fields.

Images of Japan's Noto Peninsula shared on X (formerly Twitter) by Nahel Belgherze show coastal areas where the seafloor has risen above the water, creating newly exposed beaches. The photos capture the coastline changes after the earthquake and tsunami had already subsided, leaving some ports completely dry and inaccessible to boats.

"During a field investigation along the northwest coast of the Noto Peninsula, we found evidence at 10 locations, from Kaiso to Akasaki sites, of coseismic coastal uplift related to the Noto Peninsula Earthquake (M7.6)," researchers with the Earthquake Research Institute at the University of Tokyo said in a statement on Jan. 4. 

Related: Deadly swarm of earthquakes in Japan caused by magma moving through extinct volcano

"The pattern of estimated coseismic coastal uplift appears to be decreasing southward from Kaiso to Akasaki," they added.

The area near Akasaki port also experienced nearly 14-foot-high (4.2 meters) tsunamis, according to the university's field investigations that revealed water stains on building walls.

The Japan Aerospace Exploration Agency's (JAXA) Advanced Land Observing Satellite-2 (ALOS-2) also captured the coastal uplift caused by the earthquake. Satellite images compare the coastline from June 2023 to Jan. 2, showing how the shoreline shifted seaward in multiple areas, including Nafune port, Wajima city and Minazuki bay, according to a statement from the Geospatial Information Authority of Japan.

While the satellite images capture significant changes following the Jan. 1 earthquake, investigations along the coast are still ongoing, according to the statement.

Originally posted on Space.com.

2024 is slated to be an exciting and prolific year for space missions.

In the first half of the year, there will be four attempts to land on the moon — two from the U.S. and one each from Japan and China — and each successful mission would make history. The second half of the year will feature the debut of Europe's Ariane 6 rocket, another trip to the asteroid Dimorphos, a mission to assess the habitability of Jupiter's icy moon Europa, and more.

Here are the coolest space missions to look forward to this year.

1. Peregrine moon lander

For the first time since the Apollo program ended more than 50 years ago, spacecraft are set to land on the moon. Two private companies, Pittsburgh-based Astrobotic and Houston-based Intuitive Machines, are each planning to land a spacecraft on the moon early this year.

On Jan. 8, Astrobotic will launch its box-like, four-legged Peregrine lander from Cape Canaveral, Florida. If all goes according to plan, the spacecraft would touch down on Feb. 23 in Sinus Viscositatis (aka "The Bay of Stickiness") and operate for eight days. Equipped with 20 payloads from various government and private entities, the spacecraft would be the first to study an enigmatic patch known as Gruithuisen Domes, the region adjacent to its landing site. While the domes appear to have been created from magma rich in silica, scientists cannot explain how these domes would have formed on the moon without water and plate tectonics.

The second U.S. mission to the moon, Intuitive Machines' IM-1, will now launch in mid-February after unfavorable weather conditions delayed the original Jan. 12-16 launch window. The mission would deliver the Nova-C lander to the rim of the Malapert A crater near the moon's south pole.

Related: Humanity's future on the moon: Why Russia, India and other countries are racing to the lunar south pole

2. Japan's "moon sniper"

On Jan. 20, the Japan Aerospace Exploration Agency (JAXA) plans to touch down its robotic Smart Lander for Investigating Moon (SLIM) lander, nicknamed "moon sniper," on the near side of the moon. Its goal is to arrive within 328 feet (100 meters) of its target landing site, the rim of the Shioli impact crater, which may reveal more insight into how the moon formed. If successful, Japan would become only the fifth nation to land a spacecraft on the moon (after the Soviet Union, the U.S., China and India).

3. China's sample-return mission from the moon's far side

In May, China plans to send its Chang'e 6 spacecraft to collect rocks from the moon's far side. While China's space agency has not revealed the spacecraft's precise landing site, the touchdown region would be the South Pole-Aitken Basin, a 4 billion-year-old impact basin and the largest well-preserved area on the lunar far side. Samples collected in this region are thought to be blasted from the moon's mantle and may hold hints about early evolution of the moon, Earth and perhaps even the solar system.

4. Ariane 6's inaugural launch

The debut launch of Europe's long-delayed Ariane 6 heavy-lift rocket will occur between June 15 and July 31, European Space Agency officials announced in late November. Europe currently does not have independent access to space; Ariane 6's predecessor, Ariane 5, was retired in July 2022, and another smaller rocket, Vega-C, remains grounded due to technical failures. So Ariane 6's successful first flight would be momentous for the continent, allowing it to once again independently launch satellites into orbit.

5. Hera mission to asteroid Dimorphos

In September 2022, the Double Asteroid Redirection Test (DART) spacecraft tested a planetary defense method by smashing into the asteroid Dimorphos, located about 6.8 million miles (11 million km) from Earth, shortening its orbit by 32 minutes. To study the aftermath of this collision, a European sequel mission, Hera, will launch in October, with a goal to rendezvous with Dimorphos in late 2026 or early 2027. The mission is designed to study the crater DART left behind and to document the physical properties of Dimorphos and its asteroid companion, Didymos.

Related: The 8 most Earth-shattering asteroid discoveries of 2023

6. Japan's sample return mission from Martian moon Phobos

For decades, scientists have puzzled over the origins of the two moons of Mars, Phobos and Deimos. The moons could simply be captured asteroids — or, they may be fragments of Mars that coalesced into moons after an asteroid struck the planet's surface long ago.

To learn more, Japan plans to launch a sample return mission, Martian Moon eXploration (or MMX), in September to study Phobos, the larger of the two moons. The three-module spacecraft would first arrive in an orbit around the Red Planet in 2025. Then, the craft is expected to move into an orbit around Phobos and land a sample-collection module on the moon for a few hours to scoop about 0.02 pounds (10 g) of material from the surface. In the current plan, the MMX spacecraft will return with the collected sample and land in 2029 in an Australian military facility called the Woomera Prohibited Zone.

7. Europa Clipper

Despite being smaller than our own moon, Jupiter's moon Europa is thought to host a saltwater ocean underneath its icy shell, with twice as much water as Earth's oceans. To learn if the tiny world is hospitable to life as we know it, NASA plans to launch Europa Clipper in October as the first mission to explore an oceanic world other than Earth.

Rather than directly orbit Europa itself, the spacecraft will enter an orbit around Jupiter in 2030 such that it would spend much of the time out of the gas giant's intense radiation and intermittently fly by Europa for observations of its ocean structure and chemical makeup.

8. "Blue" and "Gold" Mars satellites

To study how and when Mars lost its atmosphere, NASA is sending two satellites — nicknamed "Blue" and "Gold" after the school colors of the University of California, Berkeley, which leads the mission — around the Red Planet in October.

The satellites are part of the Escape and Plasma Acceleration and Dynamics Explorers (EscaPADE) mission to study how the Martian atmosphere interacts with solar wind. Per the current mission plan, the satellites would provide simultaneous data from different orbital positions around Mars beginning in 2026.

9. Artemis II prepares for launch

NASA's Artemis II mission, the first to send astronauts near the moon since 1972, could launch as soon as Nov. 2024 from the Kennedy Space Center in Florida. During the 10-day trip around the moon, four astronauts — three from NASA and one from the Canadian Space Agency — will test functionality of the Orion spacecraft to determine readiness of the Artemis program for longer-duration crewed missions to the lunar surface.

10. First private mission to Venus

Finishing off 2024 would be Rocket Lab's mission to Venus. The mission is designed to look for organic material, a possible indicator of life, in the planet's atmosphere. The Venus Life Finder spacecraft, equipped with a 16-inch (40 centimeters) probe built in partnership with the Massachusetts Institute of Technology, would fly on Dec. 30 and reach Venus 1.5 years later. Once there, the spacecraft would drop a single-instrument probe into the Venusian clouds. The probe would catalog molecules for three to five minutes and determine if any are indicators of life.

Scientists in Japan have unearthed the near-complete remains of an ancient, great white shark-size sea monster that likely terrorized the ancient oceans it used to inhabit. The prehistoric predator, which researchers have named "blue dragon," has an unusual body plan that sets it apart from its extinct relatives and is unlike any living creature.

The exceptional fossils, which are around 72 million years old, were discovered along the Aridagawa River in Wakayama Prefecture on Honshu island. They belong to a never-before-seen species of mosasaur — a group of air-breathing aquatic reptiles that were apex marine predators during the Cretaceous period (145 million to 66 million years ago). The "astounding" remains are the most complete mosasaur fossils ever uncovered in Japan and the northwest Pacific, researchers wrote in a statement.

In a new study published Dec. 11 in the Journal of Systematic Palaeontology, researchers named the new mosasaur Megapterygius wakayamaensis. The new genus Megapterygius translates to "large-winged" after the creature's unusually large rear flippers, and the species name wakayamaensis recognizes the prefecture where it was found. The team nicknamed the creature the Wakayama Soryu — a soryu is a blue-colored aquatic dragon from Japanese mythology. 

Mosasaurs share a similar body plan and there is very little variation among species. But M. wakayamaensis is something of an outlier, which has surprised scientists. 

"I thought I knew them [mosasaurs] quite well by now," study lead author Takuya Konishi, a vertebrate paleontologist at the University of Cincinnati, said in the statement. But "immediately, [I knew] it was something I had never seen before."

Related: Oldest 'fish-lizard' fossils ever found suggest these sea monsters survived the 'Great Dying'

Like other mosasaurs, M. wakayamaensis had a dolphin-like torso with four paddle-like flippers, an alligator-shaped snout and a long tail. But it also had a dorsal fin like a shark or dolphin, which is not seen in any other mosasaur species. 

However, what confused researchers the most was the size of the new mosasaur's rear flippers, which were even longer than their front flippers. Not only is this a first among mosasaurs but it is also extremely uncommon among all living and extinct aquatic species. 

Almost all swimming animals have their largest flippers toward the front of their bodies, which helps them steer through the water. Having larger flippers at the rear of the body would be like driving a car by steering the rear wheels instead of the front ones, which would make it much harder to turn quickly.

"We lack any modern analog that has this kind of body morphology — from fish to penguins to sea turtles," Konishi said. "None has four large flippers they use in conjunction with a tail fin."

The researchers suspect that instead of using the rear flippers to turn, M. wakayamaensis angled them upward or downward to quickly dive down or ascend through the water column, which may have helped make them adept hunters. The dorsal fin could have made it easier for the creature to turn, which may have counteracted the extra drag from the rear flippers, they added.

"It opens a whole can of worms that challenges our understanding of how mosasaurs swim," Konishi said.

M. wakayamaensis was about the same size as great white sharks (Carcharodon carcharias), which grow to around 16 feet (4.9 meters) long. But other species could grow up to 56 feet (17 m), which is longer than a school bus.

Mosasaurs emerged around 100 million years ago and died off around 66 million years ago along with the nonavian dinosaurs after a massive asteroid struck Earth. During the last 20 million years of their existence, the terrifying sea lizards were the aquatic equivalent of Tyrannosaurs rex and sat at the top of the food chain, thanks in part to the disappearance of other top marine predators such as ichthyosaurs and pliosaurs, the researchers wrote. 

A new image taken from space shows that an island forged in volcanic fire on the Pacific Seas off Japan at the end of Oct. 2023 is still rising from the sea.

The new volcanic island, which has been named Niijima  —  meaning "new island" in Japanese  —  was imaged by the European Space Agency's (ESA's) Copernicus Sentinel-2 satellite on Nov. 27. The continued growth of the island shows that the underwater volcanic activity that birthed the island off the southern coast of Iwo Jima is continuing.

The University of Tokyo said in a statement that the origins of Niijima can be traced to a volcanic eruption that began on Oct. 21, 2023. On Oct 30, between 12:20 and 12:35 local time, scorching hot magma from this volcanic activity met the ocean and exploded, forging rock chunks several feet long and launching them over 160 feet (50 meters) into the air.

As this volcanic rubble piled up and broke the sea 750 miles (1,200 kilometers) south of Tokyo, it created the island, was also imaged from space by the NASA/U.S. Geological Survey satellite Landsat-9 on Nov. 3.

Niijima has continued to be active since its violent birth. On Nov. 27, the Japan Coast Guard shared footage on its X (Twitter) account showing the island being rocked by a new volcanic eruption.

Related: Japan's new volcanic island has erupted again — and the dramatic explosion was caught on camera

The video shows white steam and smoke pouring from the smoldering island before a massive explosion erupts from its bottom left limb. Following the blast, chunks of blackened volcanic rock followed by trails of smoke can be seen falling back to Niijima as the island is rocked by a series of smaller bursts. Despite these further explosions, the new image of Niijima seems to show the newly formed island will remain intact, at least for the time being.

Japan Meteorological Agency's volcanic division expert Yuji Usui told the Associated Press in early November that the survival of Niijima and the survival of the island could depend on the type of rock it is made from.

At the time, the sea was washing away the more crumbly rock around the island's outskirts, and volcanic activity had lulled, causing Niijima to shrink, contrary to the renewed volcanic activity and island growth seen on Nov. 27. If Niijima is made mostly of hardened lava it could be destined to stick around, whereas if it is lighter, more loosely bound rock it could be dispersed back into the Pacific.

"We just have to see the development, but the island may not last very long," Usui said.

Iwo Jima and its new island companion, Niijima, are located over a chain of underwater volcanoes that mark the so-called "Ring of Fire," a 25,000-mile (40,000-kilometer) horseshoe stretching from the southern tip of South America, running along the coast of North America, across the Bering Strait, past Japan, and down to New Zealand.

The 452 volcanoes and the underwater trenches, such as the Japan Trench, the Ryuku Trench, and the Middle America Trench that make up the Ring of Fire, are the result of the sinking of geological plates under the North American geological plate, through a process called subduction. This melts rock in the upper parts of Earth's mantle, creating magma that pushes back to the surface of Earth through cracks in the crust. This births volcanoes like the underwater examples erupting to create and grow Niijima.

The site of this new island has been a hotbed of underwater eruptions of steam and lava for many years, according to University of Tokyo researchers, meaning that this region is host to one of the globe's fastest-rising caldera volcanoes, large depressions created when volcanoes erupt and collapse.

Originally posted on Space.com.

An ancient underwater volcano riding a sinking tectonic plate off the coast of Japan may have unleashed several unexplained major earthquakes — by grinding against another tectonic plate above it, a new study finds.

The extinct underwater volcano, known as Daiichi-Kashima seamount, sits on the Pacific tectonic plate roughly 25 miles (40 kilometers) off Japan's east coast. There, three tectonic plates intersect — with the Pacific plate to the east and the Philippine plate to the south both slipping beneath the Okhotsk plate to the north. The seamount sits on a section of the plate that began descending into Earth's mantle between 150,000 and 250,000 years ago, study co-author Eunseo Choi, an associate professor at the University of Memphis' Center for Earthquake Research and Information, told Live Science.

But the seamount is still close enough to the surface to trigger earthquakes, as it currently sits less than 31 miles (50 km) deep, said lead author Sungho Lee, a postdoctoral researcher at the University of Memphis. While the majority of the seismic activity around the seamount manifests as small tremors, there have been several earthquakes between magnitudes 7 and 7.8 — in 1982 (7), 2008 (7) and 2011 (7.8) — that previous research has failed to explain, Lee told Live Science.

When a tectonic plate slips, or subducts, beneath another plate, the seamounts peppered across its surface scrape against the bottom of the overriding plate. A 2008 study suggested this friction was too weak to trigger earthquakes, creating only very small tremors, Lee said.

Related: Deadly swarm of earthquakes in Japan caused by magma moving through extinct volcano

But newer data indicate the opposite, he said. Seismic information gathered at the bottom of the ocean in Japan indicates seamounts encounter huge resistance as they ride along on a subducting plate and sometimes become stuck. "The seamount itself is almost stationary, because it has very strong friction," Lee said.

As the seamount digs into the overriding plate, stress accumulates on its leading edge. The region around the seamount becomes locked and grinds to a halt in what the authors termed a "hang up" event, while the rest of the subducting plate continues its creeping descent into Earth's mantle.

"Stress increases at the edge of the seamount and after some time, the stress propagates and migrates inward," Lee said. This buildup cannot continue infinitely, he added, and the stress is eventually released when the seamount suddenly frees itself from the overriding plate and jerks forward.

The overriding plate jolts in the opposite direction, triggering a new kind of earthquake that Lee and his colleagues called a hang-up earthquake in their study, published Nov. 20 in the Journal of Geophysical Research: Solid Earth.

Hang-up earthquakes, which can reach magnitudes much greater than 7, may have unleashed tsunamis in the past, Lee said. Sediment deposits along Japan's east coast indicate huge waves battered the coastline in 1677, after an earthquake shook an area overlapping with the Daiichi-Kashima seamount.

"The rupture of the subducted seamount thus provides the most plausible source for these great tsunami earthquakes," the researchers wrote in the study.

Daiichi-Kashima is a "prime example" of a subducting seamount that causes enormous friction, Lee said. The researchers chose this region because of the abundance of available data, but their results likely also apply to other regions of the world, he added.

It's unclear whether Daiichi-Kashima could trigger an earthquake anytime soon. "Magnitude 7 earthquakes have been occurring quite regularly," Choi said. Records show the area around the seamount has experienced large earthquakes every 20 years or so since 1920. This trend changed in 2011, when a magnitude 7.8 earthquake shook Japan just three years after a magnitude 8 earthquake in 2008.

"Another one was expected soon, but the Tōhoku earthquake disrupted the stress field, looks like, so maybe the clock has been reset," Choi said.

As for other seamounts sitting off Japan's east coast, it will take them at least a million years to reach the subduction zone and another 2 million years to trigger earthquakes, Choi said.

Editor's note: This story was updated at 12:30 EDT on Friday, Dec. 8 to provide additional information about earthquake trends on Japan's east coast over the last 100 years. 

An underwater volcano that recently gave birth to a new island in the Pacific has erupted again, sending plumes of ash and smoke into the sky, footage released by the Japan Coast Guard shows.

The volcano, which sits off the coast of Japan's Iwo Jima island in the southern part of the Izu-Ogasawara arc, previously erupted on Oct. 21. Activity ramped up over the following days, and by Oct. 30, explosions were being recorded every few minutes. Each blast flung rocks and ash into a growing pile 0.6 mile (1 kilometer) off the island's coast, eventually forming a volcanic outcrop named Niijima, meaning "new island" in Japanese.

Niijima is now visible from space, satellite images taken by the European Space Agency on Nov. 3 revealed. The new landmass measures 330 feet (100 meters) across, and its highest point is 66 feet (20 m) above sea level. The October eruptions eventually subsided, and scientists said that waves may soon erode Niijima away.

Related: Seamount twice the size of world's tallest building discovered 'hidden under the waves'

But a new eruption has rocked the baby island, the Japan Coast Guard announced on Nov. 27. "As a result of observation, eruptive activity was detected on Niijima off the coast of Okinahama on the south coast of Iwo Jima," representatives said in a translated post on X, formerly known as Twitter.

The eruption, which occurred on Nov. 23, sent ash and smoke soaring up to 660 feet (200 m) into the sky. Aerial footage shows a huge explosion of volcanic material, with rocks and other debris showering down into the sea from a dark plume. Wind appears to be blowing the smoke and ash in one direction as waves lap at the island's shore.

The recent eruptions indicate that volcanic activity is resuming in waters around Iwo Jima after a short period of quiet following an eruption in July 2022. It is unclear how the latest eruption will affect the survival of the newly formed island of Niijima. But whether the island remains intact also depends on the type of rock it is made of, experts told the AP: if it is made of lava, there is a chance Niijima could stick around. 

Iwo Jima and Niijima sit atop a string of underwater volcanoes that line the circum-Pacific Ring of Fire, a horseshoe-shaped tectonic boundary where the Pacific plate joins up with many other plates. 

The Ring of Fire — which runs from the southern tip of South America, along North America's west coast, across the Bering Strait, down through Japan and all the way to New Zealand — is the most seismically and volcanically active zone in the world.

Two new species of pygmy squid have been found in the subtropical waters of a Japanese island. These cephalopods, which are smaller than paper clips, find refuge in the coral beds and seagrass fields of Okinawa and take their names from- fairies in Japanese folklore and martial arts.

The two newly discovered creatures were described in a study published last month in the journal Marine Biology.

Related: Watch a see-through squid with demon-like eyes swim in Alaska's deep waters

 The Ryukyuan pygmy squid (Idiosepius kijimuna) derives its species name, "kijimuna," from a mythical creature in Okinawan folklore. Kijimuna are said to be red-haired, childlike creatures who live in banyan trees. Similar to kijimuna, I. kijimuna is slightly red and lives in the seagrass forests close to shore, up to 6.6 feet (2 meters) below the surface. Although the species was found back in 2018, researchers had too few specimens to write a formal description at that time, the team wrote in the study. 

The second species, the Hannan's pygmy squid (Kodama jujutsu), takes its name from underwater photographer Brandon Ryan Hannan, who originally found the creature clinging to the underside of a coral reef. This species represents a whole new genus, Kodama, also named after a mythical being. According to the new study, Kodama are ghostly, rounded tree spirits believed to dwell in ancient forests. Their presence is believed to be a sign of a healthy forest.

I. kijimuna swims smoothly, while K. jujutsu bobs along with its arms splayed outward, in order to catch hapless shrimp. These predatory water acrobatics led to the species name "jujutsu" (also spelled "jujitsu" or "jiujitsu"), a martial art. 

"Jiu-jitsu revolves around grappling and using your opponent's strength, and the Kodama jujutsu preys on shrimp larger than itself by grappling with its small arms," co-author Jeffrey Jolly, of the Marine Climate Change Unit at the Okinawa Institute of Science and Technology Graduate University, said in a statement.

Collecting these tiny creatures was tricky;  both species have a maximum length of about half an inch (1.2 centimeters). 

"There are so many other things to look at, that finding a small squid the size of a pinky fingernail is not easy," Jolly said. Not only are both teensy squid nocturnal , but according to the study, the Ryukyuansquid appear only in the winter. Their whereabouts during the summer months is a mystery.

Though these sea-dwelling creatures were discovered recently, land use threatens their habitats. 

Some marine worms have developed a strange reproduction strategy: They essentially grow a second worm on their rear ends, head and all. This bizarre twin then breaks off and swims away to mate with other swimming butts of the opposite sex. 

In a study published Nov. 22 in Scientific Reports, researchers described exactly how Japanese green syllids (Megasyllis nipponica) reproduce in this very weird way. 

Most of the 1,000 species of syllid worms live on the bottom of the ocean. When some species are ready to reproduce, they undergo major changes, developing more muscular bodies and structures that enable them to swim in the water column — meaning they can travel longer distances to find mates. Much of their body mass is converted to the production of eggs or sperm. This body form is known as an epitoke. The vast majority of species die after they reproduce.

Others, like Japanese green syllids, grow an epitoke at their tail ends — called a stolon. This structure then breaks off and swims away to locate members of the opposite sex and produce the next generation. Study co-author Toru Miura, a biologist with the Misaki Marine Biological Station at the The University of Tokyo, told Live Science that the process enables these worms to repeatedly reproduce. 

Related: Bizarre sea worm with regenerative butts named after Godzilla's monstrous nemesis

The stolon is not just a disembodied tail, though. It develops its own slightly smaller brain, two sets of eyes and four pairs of antennae. The gonads, or sex organs, develop in the stolon first, followed by the brain, eyes, antennae and a series of bristles. The stolon does not, however, have a functional mouth or digestive system. "The only task of the stolon is to spawn sperm or eggs, so they die soon after spawning," Miura said.

The researchers were curious about the expression of Hox genes — which determine the body plan of an organism — in the stolon. They initially assumed that the genes would directly mirror those in the organism itself, with genes for the head, midsection and tail expressed in the same places. "However, the head-determination genes were recruited at the position of the stolon head, indicating that a stolon consists only of a head and a tail without the mid part of the original body," Miura explained.

While the mechanism by which the stolon detaches is not yet fully understood, it likely just breaks off when it starts to wriggle. "Probably, only the outer epidermis [skin] is connected just before the detachment. At the time, the attaching stolon can autonomously move and aggressively swim, so the active swimming movement triggers the detachment," Miura said.

Once the stolon breaks away to search for love in the water column, a tiny bud matures on the remaining worm and replaces the lost tail. It then continues mucking around for food as it grows its next detachable butt.

Archaeologists in Japan have unearthed a massive stash of about 100,000 coins in Maebashi, a city about 60 miles (100 kilometers) northwest of Tokyo.

The hoard was found during excavations ahead of the construction of a factory, reported The Asahi Shimbun, a newspaper in Japan. Only 334 of the coins have been examined so far, with the oldest one originating from China and dating to 175 B.C. and the most recent coin dating to A.D. 1265, the newspaper reported.

The coins were found in 1,060 bundles, with each bundle containing about 100 coins, The Asahi Shimbun said. The oldest coin has the Chinese inscription "Banliang" engraved on it. Banliang coins were commonly made in China around 2,200 years ago; the inscription translates to "half ounce," according to the Metropolitan Museum of Art in New York City.

A number of coin hoards, including examples bigger than this one, have been found throughout Japan, Ethan Segal, an associate professor of history at Michigan State University who was not involved with the find, told Live Science in an email. "Caches of buried coins, mostly from Japan's medieval period — 13th through 16th centuries — have been found in many locations around the archipelago," he said.

It wasn't until the late seventh century that "the Japanese first started producing their own metal currency," modeling the pieces after Chinese coins with square holes in the middle, Segal said. "The hole was used so that people could string together large amounts of coins, generally 100 coins per string," Segal added. From online pictures of the hoard, it appears that many of the coins have square holes.

Related: 7.5-foot-long sword from 4th-century Japan may have 'protected' deceased from evil spirits

"The Japanese made their own coins until the mid-10th century but stopped at that time due to changes in the economy and an inadequate supply of copper ore," Segal said, with Chinese coins sometimes being used instead. Segal said he would not be surprised if many of the coins ended up being from the Northern Song dynasty (960 to 1127). The Northern Song manufactured large amounts of coins, but after they were overrun by a nomadic group called the Jurchen in the early 12th century, their coins lost value and people were more willing to use them to purchase goods abroad, Segal said.

Why bury a hoard?

A number of large coin hoards have been found in Japan, but why they were deposited is a subject of debate among scholars.

"The hoards may have functioned as a bank. Another theory is that hoarding had a symbolic meaning, possibly religious," William Farris, a professor emeritus of Japanese history at the University of Hawaii at Mānoa who wasn't involved with the find, told Live Science in an email. "I favor the theory that the coins were a type of bank for safe-keeping."

Another idea is that the Japanese buried them in times of war. "They are heavy and bulky to take with you if you have to flee hostile forces," Segal said. However, some scholars "have proposed that coins were buried as offerings to the gods," Segal said, noting that "there is no scholarly consensus."

Who buried them, and when?

Scholars may be able to determine when the hoard was buried, and perhaps who buried them. The latest coin dates to 1265, suggesting that the hoard may have been deposited not long after, Farris said. This dates to the Kamakura period, a time when warriors of Japan took on a greater role, establishing a shogunate (a system in which the emperor effectively allowed a shogun, or military governor, to rule) based at Kamakura, near modern-day Tokyo, according to the Metropolitan Museum of Art. The hoard's location and time period "suggest that the depositors were warriors in the region," Farris said.

However, dating the hoard may be premature at this point, as only a small number have been examined and it may contain coins that date to later than 1265, Segal said.

"It's more common for large coin caches like the one at Maebashi to date to the fourteenth century, when warfare was more common as the Kamakura collapsed," Segal said.

Some of the coins are on exhibit in the lobby of the Maebashi cultural protection division, a statement from the city said. Archaeologists involved with the excavation did not comment by the time of publication.

A newborn island that recently emerged from the Pacific Ocean after an underwater volcanic eruption is now visible from space, images from the European Space Agency (ESA) reveal. The satellite images show the new landmass sitting around 0.6 mile (1 kilometer) off the coast off Japan's Iwo Jima island. 

The submerged volcano began erupting on Oct. 21, with activity ramping up over the next 10 days. By Oct. 30, explosions were taking place every few minutes, according to a translated statement. The eruption threw large lumps of rock into the air, and shot a jet of gas and ash over 160 feet (50 meters) almost vertically above the water's surface.

Related: Scientists discover ancient, underwater volcano is still active — and covered in up to a million giant eggs

Since the volcano started erupting, "volcanic ash and rocks have piled up to form the new island, which is now also visible from space," a statement from the ESA said. The latest image was captured with the Landsat 9 satellite on Nov. 3. It shows Iwo Jima — which sits around 750 miles (1,200 km) south of Tokyo — before and after the latest eruption. 

Along with the new island, the volcano also produced a sea of floating pumice — an extremely porous type of rock that forms during explosive eruptions. New analysis of this pumice found its chemical composition differed from that of  ejecta from other volcanoes in this chain, according to a different translated statement. The pumice likely came from an eruption along the back-arc rift zone — the area behind a volcanic arc, the statement noted.

The latest eruption is in almost the exact same spot as one that took place in July 2022, suggesting magma activity is resuming at Iwo Jima. The eruption has now subsided,  Yuji Usui, an analyst with the Japan Meteorological Agency, told the AP. 

The new island was approximately 330 feet (100 m) wide and up to 66 feet (20 m) high, but it appears to be shrinking as the waves erode the "crumbly" rock, Usui said. Whether the new island will survive is unclear and depends on what it is made of: If it is lava, it could remain for longer. "We just have to see the development," he told the AP. 

The body of a missing student in Japan has been found alongside the corpse of a bear that likely killed him. The bear is linked to a string of other attacks in the area and follows a trend of increased bear attacks in the country this year.

On Nov. 2, police found human remains on Mount Daisengen near Fukushima in Hokkaido island. DNA analysis revealed that the remains belonged to 22-year-old university student Kanato Yanaike, who had gone missing while hiking on the mountain on Oct. 29, Japanese news site The Mainichi reported. The carcass of a brown bear (Ursus arctos) was also discovered near his body.

A postmortem of Yaniake's remains revealed that the cause of death was hemorrhagic shock from severe bleeding, which suggests that the bear likely killed him, The Mainichi Shimbun reported. 

It is currently unclear what killed the bear, but scientists from the Hokkaido Research Organization will investigate its stomach contents to see if they can learn more about its death, The Mainchini reported

The bodies were located close to a site where three other men were attacked by a brown bear on Oct. 31. Two of the men were seriously injured, but the trio managed to fight off the bear with a knife and chase it away, The Mainichi reported.

Local police are now investigating the possibility that the same bear is responsible for both attacks, as well as other recent attacks in the area.

Related: Watch as 2 male Alaskan grizzly bears fight in an epic battle 

Japan is currently suffering its worst year for bear attacks in more than a century. Since April, when the first attack was reported, at least 158 injuries and two deaths have been confirmed (not including the most recent attacks in Hokkaido mentioned at the start of this article), The Guardian recently reported. Before this year, no bear attack fatalities were recorded in the country for more than a decade.

There have been at least seven other non-fatal bear attacks in Hokkaido alone this year, according to the Japanese news site The Asahi Shimbun. 

And in April, a fisher was likely killed and beheaded by a brown bear at Lake Shumarinai, in Hokkaido, The Japan Times reported. The man's head was found in the lake, and a bear was later spotted with bloody waders hanging from its mouth, sparking a bear-hunt that resulted in a brown bear being shot and killed. It is not clear if the bear killed was responsible for the attack.

Experts believe that the uptick in attacks are the result of a decrease in the number of acorns and other foods that bears feed on. This is in stark contrast to last year, when the amount of bear food skyrocketed and resulted in a greater number of large young cubs. The combination of more large young bears and decreased food availability has likely made the situation worse.

Japan also has a rising bear population thanks to conservation efforts to revive the previously dwindling population. In Hokkaido, the number of brown bears stands at around 11,700, which is more than double the number from 1990, The Guardian reported.

This year has also seen several unusual bear attacks in other parts of the globe as well.

In January, the U.S. experienced its first fatal polar bear (Ursus maritimus) attack in more than 30 years when a mother and her infant child were mauled and killed outside of a school in Alaska. And in July, a grizzly bear (Ursus arctos horribilis) likely killed a woman on a popular hiking trail near Yellowstone National Park.

In April, a brown bear with three cubs was also suspected of killing a jogger in the Italian Alps — the first bear attack fatality in the country after wildlife officials successfully reintroduced the species to the area.

An underwater volcanic eruption on Oct. 30 has birthed a new island in the Pacific after the explosion flung huge chunks of rock into a pile off the coast of Japan's Iwo Jima island.

An aircraft belonging to the Japanese newspaper Mainichi Shimbun spotted the first signs of an eruption in the southern part of the Izu-Ogasawara arc, roughly 750 miles (1,200 kilometers) south of Tokyo, around midday local time. Explosions occurred every few minutes as red hot magma hit water below the surface, throwing large blocks of rock more than 160 feet (50 meters) into the air, according to a translated statement.

The eruption breached the ocean surface in at least two locations, researchers at the University of Tokyo said in the statement, with explosions occurring only off the southernmost tip of Iwo Jima. Rocks also piled up north of the explosion site, however, forming a round and rugged island about 330 feet (100 m) across. Waters surrounding this new island were discolored and littered with pumice, a type of extremely porous rock that forms during explosive volcanic eruptions.

"Floating pumice and discolored water occur from the entire periphery of the island, suggesting that magma is erupting from this location," researchers wrote in the statement. Rocks on the island formed a concentric pattern, they noted, but there was no sign of a crater on the surface.

Related: Scientists discover ancient, underwater volcano is still active — and covered in up to a million giant eggs

Several underwater eruptions have been recorded in this region in recent years. Known as phreatic eruptions, these events are characterized by explosions of steam and volcanic material at the surface. They are triggered when water comes into contact with sizzling magma, lava, rocks or other scalding deposits. 

Underwater, volcanic material gushing from the seabed instantly solidifies. Regular eruptions have caused Iwo Jima to rise by more than 3.3 feet (1 m) every year, making it one of the fastest-rising caldera volcanoes in the world, according to the statement.

The recent eruption was preceded by volcanic tremors that began on Oct. 21 and occurred every two minutes until Oct. 30, The Japan Times reported. An outpouring of magma underwater likely caused an existing mound of solidified magma to breach the water's surface, giving rise to the new island, Setsuya Nakada, a professor emeritus of volcanology at the University of Tokyo, told the newspaper.

The eruption is ongoing, and the constant addition of volcanic rock to the newly formed island could protect it from fast erosion.

During a previous eruption on the southeastern coast of Iwo Jima in July 2022, magma burst out of a vent for the first time, alongside phreatic explosions of ash and steam. "The location of the eruption is almost the same as the 2022 eruption and is thought to indicate the resumption of magma activity on Iwo Jima," researchers wrote in the statement.

It is unclear how long the latest eruption will last, but the new island could merge with Iwo Jima, Nakada told The Japan Times.

Following a volcanic eruption in 2021, the seabed rose to such an extent that two dozen "ghost ships" that sank in the 1945 Battle of Iwo Jima resurfaced. 

A mysterious, malevolent-looking mermaid mummy that was brought back to the U.S. from Japan more than 100 years ago appears to be a mix of fish, monkey and lizard parts that have been joined together like Frankenstein's monster, initial scans suggest. 

The haunting mummy, which is around 11.5 inches (29 centimeters) long, is known as the "Fiji mermaid" due to its similarities with an object of the same name supposedly acquired from Fiji by controversial showman P.T. Barnum in the 1840s. The mummy was purchased in Japan by an American naval officer who donated it to the Clark County Historical Society in Springfield, Ohio, in 1906. Documents supplied to the society with the mummy suggest it dates back to the mid-1800s.

Now, for the first time, researchers have investigated the mermaid's identity by carrying out X-ray and CT scans on the disheveled remains.

"This allowed us to see [the mummy] in almost every dimension in the hopes to see what was inside it," project leader Joseph Cress, a radiographer at Northern Kentucky University, told Live Science. 

Related: Are there any mythological creatures that haven't been debunked? 

The initial investigation found that the mummy appears to be made from the head and torso of a monkey sewed onto the decapitated body of a fish, while the mermaid's hands are the clawed legs from a lizard — most likely a Komodo dragon (Varanus komodoensis), Cress told Live Science.

The scans also revealed a pair of wooden stakes inside the remains — one running from head to tail and another across the shoulder blades — which were presumably added to keep the creature intact, Cress said.

The researchers are currently trying to reconstruct a more detailed model of the mermaid and its individual parts from their scans. Once the models are complete, the team plans to send them to zoos and aquariums to help identify the components on a species level.

This is not the only mummified mermaid to have undergone intensive scans recently. 

In March 2022, researchers analyzed a similar specimen that was unearthed in a hidden box in a Japanese temple. Researchers initially expected that this mermaid, which was 12 inches (30.5 cm) long and dates to the mid-1700s, was also a monkey-fish hybrid. But subsequent scans this February revealed that the mummy was predominantly made from cloth, paper and cotton, painted with sand and charcoal and held together by metal pins. Various animal parts, including mammal hair and fish skin, were stuck to the outside of the doll. 

Both mermaids most closely resemble "ningyo" — mythical fish-like creatures with human heads. In Japanese mythology, a woman is fabled to have lived for 800 years after eating one of these fictional beasts, and so the creatures became a symbol of longevity. It is therefore likely that fishers made the cryptid concoctions to sell them to wealthy people seeking to prolong their lives, Live Science previously reported.