Camera traps from inside the Chernobyl exclusion zone reveal how the occupation of Russian forces at the site in February and March 2022 altered the behavior of wildlife living in the area.

After the invasion, which involved significant armed conflict inside the exclusion zone, mammals like deer and horses became less active and spent less time moving around at night, a new study reports.

Researchers discovered the changes by comparing footage from camera traps collected during the early months of Russia's 2022 invasion with recordings from the same period a year earlier, before the conflict began. The findings, published Thursday (June 18) in the journal Science, offer a rare glimpse of how animals respond to the immediate disruption caused by warfare.

"I wish the opportunity to analyze how the unfolding invasion affected wildlife ha[d] never happened," Svitlana Kudrenko, who conducted the study as part of her PhD at the Albert Ludwig University of Freiburg in Germany, told Live Science in an email. "Unlike in preindustrial times, current interstate conflicts are highly detrimental for wildlife because of a long list of warfare, often operated remotely."

The study took place in the Chernobyl exclusion zone, a roughly 1,000-square-mile (2,600 square kilometers) area surrounding the site of the 1986 Chernobyl nuclear disaster. Following the reactor explosion, authorities evacuated the region and restricted most human activity. Over the decades, with little to no human activity, wildlife populations have flourished, turning the zone into a natural laboratory for scientists studying ecosystem recovery and animal behavior.

But in February 2022, Russian forces seized control of the region during the beginning stages of the invasion of Ukraine. Military vehicles, troop movements, weapons being fired and other wartime disturbances suddenly transformed one of Europe's most unusual wildlife refuges into an active war zone.

To investigate the impact, researchers analyzed data from camera traps already operating in the exclusion zone from 2020 to 2022. Studying the ecological effects of armed conflict is difficult because war zones are dangerous and often hard for researchers to access.

By using the existing network of automated cameras, the scientists captured wildlife responses that would have been impossible to record otherwise. In total, the team analyzed almost 2,000 photographs and videos from the exclusion zone to build a picture of behavioral changes in response to the conflict.

The images and footage revealed responses from 11 wild mammal species, ‪showing that some animals changed their behavior during periods of heavier fighting.

Several mammal species — including roe deer (Capreolus capreolus), red deer (Cervus elaphus), moose (Alces alces) and red foxes (Vulpes vulpes) — were less active during the occupation than before the conflict, especially at night, the team reported.

The findings suggest that the impact of conflict can ripple through entire ecosystems. While Russia no longer occupies the Chernobyl exclusion zone, the authors highlighted that this study still shows how animal behavior can adapt to warfare.

Camera traps could become a valuable tool for measuring the environmental costs of conflict and understanding how wildlife copes with sudden human disturbances across the globe, the researchers added.

"Our study highlights the need to develop and implement research and conservation strategies focusing on armed conflict impacts on wildlife and environment in general, especially in areas of conservation importance," Kudrenko said.

What do you know about the animal kingdom? Test your knowledge with our animal quiz!

Archaeologists in Ukraine have discovered red lumps of cinnabar — a mineral form of the highly toxic chemical mercury sulfide — in a 1,900-year-old double burial of two Scythian women, according to a recent study.

The deep-red pigment, also called vermilion, has also been found in other prehistoric graves in Europe and may have been sprinkled on the newly dead to give them a reddish "flush" of life.

But in the double burial in Ukraine, cinnabar may have also served a practical purpose: to slow the decay of older bodies. Prehistoric burials, including Scythian ones, were often reopened to inter more of the dead.

"We know that one crypt could function for up to 50 years in a row," study first author Olena Dzneladze, an archaeologist at Ukraine's National Academy of Sciences, told Live Science in an email. "We know for sure thanks to excavations that the Late Scythian crypts were opened and secondary and tertiary burials took place."

The Scythians were a diverse but culturally related group of nomads who lived on the Eurasian Steppe stretching from Ukraine to China from about 800 B.C. to A.D. 300. The double burial with cinnabar dates to the first to early second century A.D., toward the end of the culture.

The traces of cinnabar were found in a single grave containing the remains of two women at Chervony Mayak, a Late Scythian burial ground in the south of the country beside the Dnieper River. One of the women was between 35 and 45 when she died, and the remains of a younger woman, between 18 and 20, were interred in the same grave at a later time. The women were buried with several grave goods, including beads, pottery and metal items.

The site was discovered in the 1970s, and red lumps have been found in some of the graves there since 2011. But the study by Dzneladze and her colleagues, published in 2025 in the journal Antiquity, is the first to identify the lumps as cinnabar, and it is the first time cinnabar has been scientifically identified in a Late Scythian grave.

Toxic pigment

Cinnabar is highly toxic to humans, although the authors of the new study said the people who used it in first-century Ukraine may not have known that.

In some prehistoric societies, cinnabar was used in the same way as the clay-like pigment ocher (iron oxide) for body paints, cave paintings and rituals. But whereas ocher is nontoxic, cinnabar causes mercury poisoning, especially when it is heated and its poisonous gases are inhaled. Mercury then builds up in the body and can cause tremors, breathing problems and even death, and the bones of prehistoric people who were frequently exposed to cinnabar have extremely high mercury levels.

At Chervony Mayak, cinnabar may also have had other uses, the researchers wrote, including as a cosmetic or slowing decay by resisting bacteria.

Traces of the mineral have been found in only three of the 177 graves at Chervony Mayak; Scythian burials elsewhere do not have the red mineral. However, the researchers think it may have been overlooked in other Late Scythian graves.

"Often in archaeological field reports and publications we read a small description that 'red pigment,' 'a piece of ocher' or 'blush' was found in the burial, [but] without clarification and analysis," Dzneladze said. "These could be different substances."

Cosmetic purpose?

All three graves containing cinnabar at Chervony Mayak hold women, which suggests the mineral also might have had a cosmetic purpose. Dzneladze said the grave goods in male and female Scythian graves were distinct, so "we can attribute it to the complex of the female set of grave goods."

"The use of cinnabar also for cosmetic purposes should not be ruled out … Ocher and other mineral dyes were also found in [Late Scythian] female burials in pyxides [vessels], caskets and shells used for storing and diluting cosmetics," she said.

Kaare Lund Rasmussen, a professor emeritus in the Department of Physics, Chemistry and Pharmacy at the University of Southern Denmark, wasn't involved in the study but has researched cinnabar use in medieval Europe, where it was thought to be an effective medical treatment for leprosy and syphilis.

He told Live Science in an email that cinnabar had been found in earlier prehistoric burials in Europe, and so it made sense that the Late Scythian culture would also have made use of it, perhaps as a pigment.

He added that colorants like cinnabar and ocher had been found in Mesolithic period (Middle Stone Age) graves in Europe from up to 15,000 years ago, after the period of intense ice that covered large parts of northern Europe during the Last Glacial Maximum.

"In Denmark I remember a beautiful grave, a mother and her young child buried together, with the child lying on the wing of a swan — with red ochre spread over them," he said.

Around 18,000 years ago, ice age people in what is now Ukraine likely weathered the extremely harsh climate by building parts of their shelters out of mammoth bones, a new study finds.

The mammoth dwellings show how communities thrived in extreme environments, turning the remnants of giant animals into protective architecture," the archaeologists wrote in a statement.

The bones were originally found near the village of Mezhyrich, about 70 miles (110 kilometers) southeast of Kyiv. When it was excavated between 1966 and 1974, the archaeological team at the time found the mammoth remains arranged in such a way that suggested they had been used to make houses sometime during the ice age. While this interpretation has found much support among archaeologists, questions still remain about exactly when these bone dwellings were used and for how long. Earlier dates from the site gave a broad range from roughly 19,000 to 12,000 years ago, the team noted in their paper.

To investigate these questions, archaeologists re-examined the site to try and get a better idea of when it was built and how long it stayed in use. They dated the remains of about a dozen small animals found near the mammoth dwellings to try and get a more precise chronology.

The largest structure at Mezhyrich dates to 18,323 to 17,839 years ago, the team reported in the study, published on Nov. 21 on the publishing platform Open Research Europe. These dates are just after the Last Glacial Maximum (26,500 to 19,000 years ago), the coldest part of the last ice age. The researchers noted that the dwelling may have been used for up to 429 years. This indicates that the "shelters were practical solutions for survival rather than permanent settlements," they wrote in the statement.

The foundation of the shelters may have had "mammoth skulls and large long bones, set vertically into the ground [which] formed a kind of plinth or 'foundation,'" study co-author Pavlo Shydlovskyi, an archaeology professor at the Taras Shevchenko National University of Kyiv, told Live Science in an email.

A wooden framework may have covered parts of the shelter, along with hides from smaller animals or possibly birch bark. In addition, "tusks and large flat bones were placed on the upper part of the structure [the roof] functioning as weights and wind protection," Shydlovskyi said.

Five to seven people likely lived within each shelter, Shydlovskyi said. A variety of activities such as flint knapping, animal skin processing and small animal butchering were likely done inside.

Francois Djindjian, an honorary professor at the University of Paris 1 Panthéon Sorbonne has done research on other possible mammoth bone shelters but was not involved in the new paper. He was cautious about the team's dates, and said that he thought that more dates were needed from more of the site. Getting more radiocarbon dates from across the site would give a better idea of when it was used.

Last ice age quiz: How much do you know about Earth's frosty past?

Neanderthals crafted red and yellow "crayons" tens of thousands of years ago, using different techniques to sharpen the instruments' edges into a perfect point, a new study finds.

These Neanderthals, who lived in what is now Crimea, sculpted their crayons out of ocher (also spelled ochre), an iron-containing mineral that can be used as pigment. In the new study, the researchers identified three ocher crayons dating up to 100,000 years ago that appeared to have had "curated use," including one with a sharpened tip.

The finding adds evidence to the debate as to whether Neanderthals were capable of creating art that was symbolic. In this case, although the authors did not discover any actual markings, they suggested that if the Neanderthals had used the ocher for other tasks, such as tanning hides, they would not have required the pointed tip.

The discovery of the crayon with evidence of repeated sharpening suggests that Neanderthals in Crimea sometimes used ocher for socially and culturally meaningful tasks, such as drawing body markings, according to research published Wednesday (Oct. 29) in the journal Science Advances.

Finding a fragment where the tip was clearly resharpened was exciting, said study first author Francesco d'Errico, a professor of archaeology at the University of Bergen in Norway, as it shows the crayon was crafted and maintained for drawing fine lines. "This is really something very special," he said.

However, not everyone agrees with the researchers' interpretations, telling Live Science that there is no direct evidence that these ocher crayons were used to draw cultural or social artwork.

This conclusion would hint at Neanderthals possessing the brain power to create social signifiers and to transform their bodies into cultural objects like our own species, Homo sapiens, does, d'Errico told Live Science.

Prehistoric pigments

Prehistoric humans and their relatives have been playing with pigments for hundreds of thousands of years. So far, almost 40 sites across Europe show evidence of Neanderthals using black, red, yellow or white pigments, but not all uses were for social or cultural purposes.

For example, Neanderthals living in Iberia around 50,000 years ago used red and yellow pigments to paint shells, suggesting symbolic use, while Neanderthals living in what is now the Netherlands were using black minerals 200,000 to 250,000 years ago without evidence of symbolic meaning.

However, there is less clear evidence of Neanderthals using ocher in Eastern Europe and western Asia, and the cultural variants found in those regions have received less attention, the authors wrote in the study.

To determine whether the previously unearthed ocher found at Crimean Neanderthal sites could have been used to create cultural meaning, the researchers focused on 16 ocher fragments from three Crimean rock shelters and one northeastern Ukrainian open air site dated from around 100,000 to 33,000 years ago.

The team closely inspected the ocher fragments' shape and markings to see how they were crafted and used, and examined the elemental makeup of each fragment to determine where it originated.

D'Errico and his team found three fragments, all from Crimea, that they say were likely used for culturally meaningful purposes rather than simply for practical uses, such as tanning hides or repelling insects.

The first was a tool that had been repeatedly scraped and ground to sharpen its point after it became too blunt. This indicates that the ocher was used like a colored pencil to draw thin lines on surfaces such as skin or stones, the researchers suggested. Another fragment appeared to be part of a broken crayon, while a third piece had lines purposefully engraved into its base.

The ocher was sourced from the local outcrop, as well as other currently unknown locations, the team found. D'Errico said that tracing where Neanderthals obtained their coloring materials provides a window into the choices these individuals made and how they perceived differences in color and quality. However, the current sample of crayons is too small to reach any firm conclusions on these individuals' decision making, he added.

A few disagreements

Rebecca Wragg Sykes, an archaeologist at the University of Cambridge and author of "Kindred: Neanderthal Life, Love, Death and Art" (Bloomsbury Sigma, 2020) who was not involved in the study, is not convinced by the authors' conclusions.

"The researchers' argument that there is direct evidence for symbolic use here is not necessarily the only interpretation," she told Live Science in an email.

For example, she said that the etchings on the side of one of the fragments do not necessarily mean it was culturally meaningful to the users. "The markings can be understood as a particular powder production method, without implying there was a particular symbolic meaning to them (e.g. as a recurring 'motif' or pattern)," she suggested.

But while the markings themselves may not have symbolic meaning, Neanderthals may have still used colored powders to that end, Wragg Sykes noted.

"The fact I do not think there is strong evidence here for intentional engraved motifs doesn't mean that there was no aesthetic, socially meaningful element in why Neanderthals were making and using coloured powder," she added.

April Nowell, a Paleolithic anthropologist at the University of Victoria in British Columbia who was not involved in the research, argues that there should be less focus on the distinction between symbolic and practical ocher use. Once Neanderthals started to use ocher for practical purposes, such as insect repellent, they likely also developed it for body painting and clothing designs to differentiate individuals or groups, as in nonindustrialized societies today, she told Live Science in an email.

Neanderthal quiz: How much do you know about our closest relatives?

Easter-egg decorating is an ancient tradition with deep roots extending at least into the medieval period of European history. But archaeological evidence of them is scarce due to the delicate nature of eggshells. At more than 500 years old, the Lviv pysanka — Ukrainian for "written egg" — is the oldest decorated Easter egg in the world.

Archaeologists discovered the pysanka in 2013, when construction workers stumbled upon a medieval well while renovating a house in Lviv, a city in western Ukraine. The well was originally used for collecting groundwater, according to the Rescue Archaeological Service at the Ukrainian National Academy of Sciences' Institute of Archaeology. But after the Great Fire of Lviv in 1527, which destroyed most of the city, the well was used as a cesspit.

The pysanka was nestled in a thick layer of charcoal along with ceramic dishes; small utensils; and leather, wood and metal objects, suggesting that these items may have been swept into the disused well during cleanup after the fire. Surprisingly, the damage to the egg was minor; only about 0.31 square inches (2 square centimeters) of the total area was lost.

Related: Słupcio: A 6,000-year-old amber 'gummy bear' that may have been a Stone Age amulet

Ukrainian pysanky are typically created using a wax-resist technique. With this method, wax is "written" in a decorative pattern on the surface of the egg, which is painted or dyed. The wax is then removed, revealing the light-colored shell of the egg, which, in the case of the Lviv pysanka, is from a duck.

The practice of decorating ceramic eggs or balls dates back many centuries. Archaeologists have found ceramic Easter eggs in Ukraine dated to the 12th century, revealing the antiquity of the practice in that country. And some researchers argue that decorated eggs date back several millennia, originating with the Stone Age Cucuteni-Trypillia culture in Central Europe, likely as a symbol of nature and rebirth. But this pagan tradition was eventually absorbed into Christianity, with the egg coming to symbolize the empty tomb and the resurrection of Jesus Christ.

In modern Ukraine, decorating pysanky is an important national tradition. In 2024, UNESCO listed Ukrainian pysanky decorating among the Intangible Cultural Heritage of Humanity, honoring the centuries-old practice.

The Lviv Easter egg is currently housed in the Pysanka Museum in Kolomyia, which displays many of these symbols of the long-standing Ukrainian tradition of egg decorating.

Burnt and battered human bones from 5,700 years ago hint at a brutal end for a group of Stone Age people who likely died in a house fire in what is now Ukraine, a new study finds.

But why two of the people had violent head injuries and why one died a century later than everyone else remain unsolved mysteries.

"We can only speculate whether there was a connection between the fire and the act of deadly violence, i.e. killing the people in the house, leaving their corpses, and setting the house on fire," Katharina Fuchs, a biological anthropologist at Kiel University in Germany, and colleagues wrote in a study published Wednesday (Dec. 11) in the journal PLOS One.

In 2004, archaeologists discovered nearly 100 pieces of human bone in a prehistoric house at Kosenivka, an archaeological site about 115 miles (185 kilometers) south of Kyiv. Kosenivka preserves the remains of a prehistoric "mega-settlement" created by the agrarian Cucuteni-Trypillia societies (CTS), who lived throughout what is now modern-day Romania, Moldova and Ukraine from 4800 to 3000 B.C. These settlements consisted of public buildings and family houses, many of which were deliberately burned down when people left.

But the discovery of human bones within one of the burned houses at Kosenivka surprised archaeologists, who undertook the new detailed study to figure out what happened.

Related: Strange pile of Stone Age skulls unearthed in Italian village baffles archaeologists

A close look at the bones revealed the remains of at least seven people: two children, one adolescent and four adults. Four of the skeletons were found inside the destroyed house and were heavily burnt, while the other three were unburned and found outside the dwelling. The researchers discovered that two of the adults had suffered violent head trauma just before their deaths, setting up a 5,700-year-old forensic mystery.

To investigate this cold case, the research team used radiocarbon dating to determine that six people, possibly a family, likely died between 3690 and 3620 B.C., while the seventh — an unburned adult — died roughly 130 later, after the house burned and was abandoned. Then, they looked closely at the bones' fracture patterns and discoloration to figure out that the bones were scorched while still fresh.

Given the contemporaneous dates of death and the evidence of burning, the team deduced that three people may have died inside the burning house, while others may have been overcome by smoke inhalation or carbon monoxide poisoning and died just outside the house. However, this analysis did not reveal further information about the cause of the skull injuries.

Regardless of how these six Stone Age people died, it is clear that the house and bodies were completely covered with soil and debris within a matter of months and that part of someone else's skull was placed on top a century later, the study authors explained.

The isolated skull fragment could be a deliberate ritual deposition, the researchers wrote, and the whole collection of bones could be the result of a complex, multistage burial tradition. Unfortunately, Fuchs told Live Science in an email, "although they left us a tremendous amount of archaeological material, there are still so many things we do not know — for instance, how they treated their dead."

"It seems reasonable that the individuals recovered from Kosenivka were killed during a raid and that their house was lit on fire during the conflict," Jordan Karsten, an archaeologist at the University of Wisconsin Oshkosh who was not involved in the study, told Live Science in an email. "Previous explanations [for burned CTS houses] have focused on ritual house destruction through intentional burning, but these results suggest that intergroup conflict might better fit the data."

Economically, it makes little sense to burn down a home full of food, ceramics, tools and ritual items, and the CTS people lived in a forested steppe area near nomadic pastoralist groups.

"Rather than destroy their own homes, doesn't it seem just as likely that these neighbors would do it?" Karsten said.

Three "truly sensational" Roman-era silver ingots depicting Constantine the Great were nearly sold illegally on the internet, a new investigation finds.

An unnamed man alleged that his great-grandmother found the rare artifacts buried in the family's backyard in Transcarpathia (also known as Zakarpattia), a region in western Ukraine. Later, the man reportedly tried to sell one of the silver bars online, according to Public Uzhgorod, Ukraine's public broadcast station.

However, officials from the museum intervened by reporting the attempted illegal sale to local law enforcement. When officers searched the home, they discovered two additional ingots. Because the ingots have "special cultural value," Ukraine's Office of the Prosecutor General has taken over the case, according to a translated statement from the National Museum of the History of Ukraine in Kyiv.

Each of the metal blocks, which are almost entirely pure silver, weighs more than 12 ounces (342 grams) and contains a coin-shaped impression of Emperor Constantine the Great on each side, according to the statement. Constantine, who ruled from A.D. 306 to 337, is known for ushering Christianity into the Roman Empire and moving his capital to "New Rome," which later became Constantinople (modern-day Istanbul).

The ingots would have been used during the minting process to strike coins known as siliquae. The coins with Constantine's likeness would have been issued between A.D. 310 and 313 in Augusta Treverorum, a Roman city that today is Trier, Germany. At one time, the pieces would have been batched together with a thin, silver ribbon, which has since been lost, according to the statement.

Related: Russian forces repeatedly stole priceless Scythian treasures from Ukrainian museum

"Three ingots fastened together were supposed to be a gift for a very high-ranking person," Maksym Levada, a curator at the museum, said in the statement. "The fact that they were found outside the Roman Empire on the territory of modern Ukraine makes them an invaluable source of our past." 

Experts estimate the treasure's value at 3.5 million Ukrainian hryvnia, or about $84,800.

"But what makes them unique is not the cost, but the fact that only a few similar ingots have been found in Europe to date," Andriy Kostin, Ukraine's prosecutor general, said in the statement.

There are about 90 known Roman silver ingots in existence today, with only 11 containing mint stamp impressions, making the three ingots' recovery even rarer, according to the statement.

Kyrylo Myzgin, an archaeologist and faculty member at the University of Warsaw who initially examined the ingots, told Live Science in an email that the finding "can be considered truly sensational." 

"It is excellent news that they ended up in a museum rather than on the black market for antiquities," Myzgin said. "Roman silver ingots with coin die imprints are incredibly rare and were virtually unknown outside the Roman Empire. It is likely that these ingots reached the territory of what is now western Ukraine as a result of interactions between the local population — possibly Germanic tribes or Dacians [people in what is now largely modern-day Romania] — and the Roman Empire in the early 4th century. However, the exact nature of these interactions has yet to be determined."

The ingots are now on display in the museum's "Salvated Treasures" exhibition, which contains a collection of rescued artifacts.

Tiny worms in the Chernobyl Exclusion Zone (CEZ) in Ukraine are thriving despite being in an area marked by high levels of radiation, and scientists think their resilience could provide insights for cancer research in humans.

Researchers traveled to the CEZ and collected microscopic worms of the species Oscheius tipulae. Upon analyzing these worms, which live in the fallout of the Chernobyl (or Chornobyl) nuclear disaster, scientists discovered that their genomes — the complete set of genes that make up an organism — have not been damaged. This is despite generations of the animals being exposed to radiation, according to a study published March 5 in the journal PNAS. 

"Chornobyl was a tragedy of incomprehensible scale, but we still don't have a great grasp on the effects of the disaster on local populations," study lead author Sophia Tintori, a postdoctoral associate in the Department of Biology at New York University, said in a statement. "Did the sudden environmental shift select for species, or even individuals within a species, that are naturally more resistant to ionizing radiation?"

Scientists sequenced the genomes of 15 of the CEZ worms exposed to different levels of radiation, along with five from other parts of the world, and were unable to detect any clear signs of radiation damage in the worms from the CEZ. These results are in stark contrast to other animals, including frogs, which have changed physically after radiation exposure at the site. 

"This doesn't mean that Chornobyl is safe — it more likely means that nematodes are really resilient animals and can withstand extreme conditions," Tintori said. "We also don't know how long each of the worms we collected was in the Zone, so we can't be sure exactly what level of exposure each worm and its ancestors received over the past four decades."

Related: Scientists finally figured out what's making German wild boars radioactive, and it's not just Chernobyl

Researchers wondered if this was simply a case of the worms being particularly adept at repairing their DNA.

To find out, they let the 20 worms breed in the lab, then tested their descendants to see how they responded to exposure to various chemicals that damage DNA. 

The lineages, or strains, differed in how well they could resist DNA mutation in response to the chemicals — but there was no correlation in how well the worms resisted DNA damage and the levels of radiation their ancestors were exposed to.  

This suggested that the Chernobyl worms were not "necessarily more tolerant of radiation and the radioactive landscape has not forced them to evolve," according to the statement.

Instead, some other factors, not yet identified, may explain why some worms are better at resisting DNA damage than others. The study authors now want to investigate what those factors are and whether they could shed light on why some people are more susceptible to cancer than others.

"Now that we know which strains of O. tipulae are more sensitive or more tolerant to DNA damage," Tintori said, "we can use these strains to study why different individuals are more likely than others to suffer the effects of carcinogens."

The Doomsday Clock, whose hypothetical hands strike the minutes and seconds left until a human-made apocalypse destroys the world as we know it, has remained at just 90 seconds to midnight.

The clock moved to 90 seconds to midnight for the first time ever last year, after hovering at 100 seconds to midnight for three consecutive years as the world teetered on the "doorstep of doom." The clock's hands remain in this critical position mainly because of the existential risk posed by climate change and nuclear escalation in Russia's ongoing assault on Ukraine, representatives of the Bulletin of the Atomic Scientists (BAS) announced on Tuesday (Jan. 23). The BAS is a non-profit organization of scientists and policy-experts that sets the time of the Doomsday Clock. 

Representatives also cited disruptive technologies — including cutting-edge bioresearch and vectors for misinformation — as dangers contributing to our dash toward self-destruction.

The time of the Doomsday Clock is decided by the BAS's Science and Security Board (SASB), which this year featured science educator Bill Nye, and the organization's board of sponsors, which includes 15 Nobel laureates.

"The Bulletin SASB took into account developments across many different domains, including a broad range of events or factors that relate to the possibility of nuclear war, to climate change, to biological threats such as pandemics or biological weapons, and to emerging technologies that may prove disruptive to peace and stability," Herbert Lin, a senior research scholar at the Center for International Security and Cooperation at Stanford University who sits on the SASB, told Live Science in an email. 

Related: Catastrophic climate 'doom loops' could start in just 15 years, new study warns

Chief among these potentially world-ending new technologies is artificial intelligence (AI), Lin said. AI technology progressed by leaps and bounds last year, but 2024 may be the year it changes our lives. 

The BAS created the Doomsday Clock in 1947 to warn against the existential threat posed by nuclear weapons, initially setting it to seven minutes to midnight. The clock jumped to three minutes to midnight two years later, following the first successful Soviet atomic bomb test during the Cold War between the U.S. and the Soviet Union. It lurched another minute closer to midnight in 1953, after the detonation of the first hydrogen bombs but was again set to seven minutes in 1960. Its hands can and have moved even further backward — in 1991, they moved to 17 minutes to midnight after the collapse of the Soviet Union and the signing of the Strategic Arms Reduction Treaty that agreed to reduce the number of long-range nuclear weapons in the U.S. and former Soviet Union.

The clock re-entered the two-minute-warning zone in 2018 for the first time since 1960 due to "reckless language in the nuclear realm" and a world "on the cusp of a new arms race," BAS president and CEO Rachel Bronson wrote in a statement at the time.

Over the past six years, the clock has gradually crept closer to midnight.

The decision to move the clock forward last year was largely based on humanity's inaction on climate change and fears over the war in Ukraine. But there were a number of other factors. "For many years we have also considered various disruptive technologies from online misinformation to new bioresearch," Bronson said in a statement shared with Live Science. "This year, the technology conversation must also include the recent rapid advancements in AI."

New technologies pose dangers of their own, but they also have the power to exacerbate existing challenges. "We also call attention to the threat of the corruption of the global information environment that acts as a threat multiplier," Lin said. "The abundance of mis and disinformation about nuclear, climate, and pandemic threats makes those problems enormously harder to solve because it works against the political consensus needed to tackle them seriously."

The Bulletin's board members hope the new announcement will galvanize governments into action, Lin said.

"There is some progress, ranging from early-stage nuclear diplomacy between the U.S. and China to record-breaking investments in renewables [and] emerging national and international policy frameworks around technologies like AI and biological research," Bronson said. "But none of these efforts are moving forward quickly enough."

Archaeologists in Ukraine have discovered a 1,000-year-old cemetery whose dead were buried with weapons, jewelry and, curiously, buckets around some of their feet.

The 11th-century cemetery is located about 50 miles (80 kilometers) south of Kyiv. Of its 107 graves, "most of the identified burials were deposed in wooden coffins," Vsevolod Ivakin and Vyacheslav Baranov, both archaeologists at the National Academy of Sciences of Ukraine, wrote in a paper they presented at the annual meeting of the Archaeological Institute of America, which was held Jan. 4-7 in Chicago.

The cemetery's dead include both men and women. Some of the men were buried with weapons, such as axes, spearheads and swords, Ivakin and Baranov wrote. A few of the women were buried with elaborate neck rings, which "are found only on necks in female burials and were apparently a kind of social marker," in this region at the time, Baranov told Live Science in an email. Some of the people were buried with wooden buckets at their feet, which may have been part of funerary rituals. Other sites that have buckets within burials have been found in the region.

Related: Russian forces reportedly stole priceless Scythian treasures from Ukrainian museum

The archaeologists also found a stone altar, as well as bracelets, beads and the remains of food offerings, such as chicken bones and eggshells, among other artifacts. The altar could have been used for Christian or pagan rituals, or possibly both.

Some of the artifacts are similar to those found in the Baltic, hinting that some of the people buried in the cemetery might have come from that region to serve in the militaries of the rulers of Kyiv, such as Volodymyr the Great (who reigned from 980 to 1015) and Yaroslav the Wise (who reigned from 1019 to 1054), the archaeologists noted. The territories that Volodymyr the Great ruled stretched to the Baltic region.

At the time the cemetery was in use, people in Ukraine were converting to Christianity, the researchers said. This included Volodymyr the Great, who left behind his pagan roots and was baptized around 987 before his marriage to Anna, the sister of the Byzantine emperor Basil II.

The researchers excavated the cemetery between 2017 and 2022. The ongoing Russian invasion of Ukraine, however, has paused many excavations in Ukraine, including this one, the archaeologists said.

Nearly 80 years since they last flew, eight British Hawker Hurricane fighter aircraft from World War II have been uncovered in a forest near the Ukrainian capital, Kyiv.

The aircraft, now rusted and in fragments, were buried there after the war's end, likely by the Soviet Union in an attempt to avoid paying the United States for them under the Lend-Lease program. 

Despite the secretive burial, rumors had circulated for many years about the discarded aircraft near an old airfield on the outskirts of Kyiv, according to a statement from Ukraine's Oleg Antonov State Aviation Museum in Kyiv.

The wrecks were located earlier this year after an unexploded wartime bomb was found and defused in a ravine nearby. The ravine was then checked with metal detectors, which revealed the underground remains, according to BBC News.

The wrecks of the fighter aircraft have now been dug up by volunteers and donated to the aviation museum, where they'll be preserved for display.

Related: 30 incredible sunken wrecks from WWI and WWII

"It is very rare to find this aircraft in Ukraine," Oleks Shtan, a former airline pilot who led the excavation, told BBC News. "It's very important for our aviation history because no Lend-Lease aircraft have been found here before."

Vital fighters

Although they're often overshadowed by the U.K.'s newer and faster Spitfire fighters from WWII, Hawker Hurricanes were instrumental in the Allied victory over the Axis powers led by Nazi Germany.

The single-seat aircraft were used in every theater of the war and on warships as Sea Hurricanes, which were often launched from catapults.

The Royal Air Force's Hurricane fighters also shot down more than half of the enemy aircraft destroyed during the Battle of Britain in 1940, when the German Luftwaffe launched thousands of large-scale attacks in an attempt to force the U.K. to surrender. 

"The Hurricane was a strong, easy to fly machine," Shtan said "It was stable as a gun platform and suitable for inexperienced pilots." 

According to BBC News, the buried aircraft were among 3,000 Hurricanes sent to the Soviet Union after 1941; the U.S. purchased them from the U.K. under the Lend-Lease program, in which the U.S. funded the Allied war effort from 1941 to 1945.

The Hurricanes were then transferred to the Soviet Union, with the understanding that the Soviets would repay the U.S. for any aircraft that were still intact at the end of the war.

But the Hurricanes near Kyiv were stripped of parts and dumped into the ravine after the war, a tactic that got the Soviet Union off the hook for their payment, according to BBC News.

Ukraine was the southernmost part of the Soviet Union in Europe until its independence in 1991; and it was the scene of several major battles after the invasion by Nazi Germany in 1941.

Like the U.S., the U.K. is now a contributor to Ukraine's efforts to fight an invasion of its territory by Russia, which started in February 2022.

"The Hurricanes are a symbol of British assistance during the years of the Second World War, just as we are very appreciative of British assistance nowadays," Valerii Romanenko, the head of research at the aviation museum, told BBC News. "The U.K. is one of the largest suppliers of military equipment to our country now."

NASA has denied claims made by Kyiv’s city authorities that a mysterious, dazzling flash of light above Ukraine’s capital was caused by one of its defunct satellites tumbling to Earth.

The bright flash, which was seen over the city at around 10 p.m. local time (3 p.m. EDT), prompted the city’s authorities to turn on air raid alerts. Citing early data, Serhiy Popko, the head of the city’s military administration, said on Telegram that the "phenomenon was the result of a Nasa space satellite falling to Earth."

But NASA later refuted this, saying that at the time the flash occurred, its satellite — the dead, 660-pound (300 kilograms) Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) satellite — was still in orbit.

Related: US shoots down UFOs over Lake Huron and Canada

“One more time: the bright flash seen over Kyiv has NOTHING TO DO with the reentry of NASA's RHESSI satellite, whose orbit doesn't come within thousands of kilometers of Ukraine,” Jonathan McDowell, an astronomer at the Harvard Smithsonian Center for Astrophysics in Massachusetts, wrote on Twitter.

NASA's most up-to-date prediction suggest the satellite hurtled through our atmosphere at 8:50 p.m. EDT on Wednesday, April 19 (12:50  a.m. UTC on Thursday, April 20), plus or minus 1 hour. The space agency hasn’t announced that the satellite has landed yet, or where. McDowell, who has been tracking the falling space junk, said that RHESSI’s possible debris field could fall over anywhere from southern South America, to northern Africa, Central Asia or China.

The mysterious flash above Kyiv has filled Ukrainian social media with popular memes and conspiracy theories — many speculating that aliens aboard UFOs were the cause of the light in the sky. It is not the first time mysterious objects have been seen over the country, but Ukraine’s space agency has said (in Ukrainian) that the flash was likely from a meteorite exploding into a fireball as it entered Earth’s atmosphere.

RHESSI was launched into a low-Earth orbit by the Pegasus XL rocket in 2002. The satellite used a spectrometer that detected X-rays and gamma rays — high-energy waves from the sun that are largely blocked by Earth's atmosphere — to capture data on eruptions from the sun in the form of solar flares and coronal mass ejections (CMEs).

The satellite is just one of many potentially hazardous pieces of space junk that have made headlines after tumbling uncontrollably out of orbit. Four of China's Long March 5B boosters — the workhorses of the country's growing space program — fell to Earth between 2020 and 2022, raining debris down on the Ivory Coast, Borneo and the Indian Ocean. In 2021 and 2022, debris from falling SpaceX rockets smashed into a farm in Washington state and landed on a sheep farm in Australia. 

Space agencies around the world try to keep tabs on the more than 30,000 largest pieces of this junk, but many more pieces of debris are simply too small to monitor.

Ukrainian military doctors have successfully completed a rare and dangerous operation — removing an unexploded grenade from a patient's chest, according to senior Ukrainian officials.

On Jan. 9, Hanna Maliar, Ukraine's deputy minister of defense, posted an X-ray image on Facebook showing the unexploded ordnance lodged inside the chest of a Ukrainian soldier.

"Military doctors conducted an operation to remove a VOG grenade, which did not break, from the body of the soldier," she wrote.

Maliar wrote that Andrii Verba, one of the most experienced surgeons in Ukraine's armed forces, carried out the operation, and that he was assisted by two sappers, or combat engineers, to protect medical staff and make sure the operation was done safely. Alongside the patient X-ray, Maliar’s post shows Verba holding the grenade after it was removed. VOG grenades are around 1.6 inches (4 centimeters) long and can be fired from grenade launchers as far as 0.2 mile (400 meters) from a target, according to the BBC.

Maliar also wrote that doctors did not use electrocoagulation during the surgery —  a common method to control bleeding that works by using electric current to burn the edges of blood vessels, cauterizing a wound or incision. In this case, doctors feared the electric current would set off the grenade.

"The unexploded part of the grenade was taken from under the heart. The grenade did not explode, but remained explosive," wrote Anton Gerashchenko, Ukraine's internal affairs ministerial adviser, in an update on Telegram (translated from Ukrainian). He said that the patient is about 28 years old and is undergoing further rehabilitation and recovery.

"There have never been such operations in the practice of our doctors," he wrote.

The operation may be a first in the current war between Ukraine and Russia, but surgeries like it have happened before. A 1999 study in the journal Military Medicine looked at U.S. military data and found 36 cases of unexploded ordnance being removed from patients between World War II and the study's publication. Though four patients died of their injuries before surgery could be attempted, the other 32 operations were successful.

In 2006, a team of U.S. military doctors in Afghanistan removed an unexploded grenade from the abdomen of Pvt. Channing Moss, a U.S. soldier. And in 2014, doctors removed potentially explosive ammunition from the head of a 23-year-old pregnant woman in Afghanistan. Though the object turned out to be a non-explosive metal bullet, doctors took precautions similar to those taken by Ukrainian doctors in the recent case, such as forgoing the use of an electrocautery device, which they documented in a 2016 case report. The U.S. Department of Defense's Joint Trauma System even has official guidance on how to handle such cases.

Nevertheless, the successful Ukrainian surgery marks a case where everything went right in a nerve-wracking, potentially deadly situation.

"I think this case will go down in medical textbooks," wrote Gerashchenko. 

Predicting the future is tricky, but based on our research, we've made some educated guesses as to the archaeological discoveries and stories we may see in 2023. There's a possibility that the mummy of Nefertiti will be discovered, as archaeologists are conducting DNA tests in an Egyptian tomb to see if one of the mummies is the remains of the ancient Egyptian queen. We also may learn more about an underground city that flourished in Turkey about 2,000 years ago. Here are our five archaeological predictions for 2023.

1. Nefertiti's mummy?

First found in modern times in 1817, the tomb "KV 21," as Egyptologists call it, is located in the Valley of the Kings and contains two female mummies, according to the Theban Mapping Project. At present, a team led by Zahi Hawass, former Egyptian minister of antiquities, is re-examining the tomb and its mummies by conducting DNA tests. Hawass told Live Science that the team is examining the possibility that one of the mummies is Nefertiti. While it's uncertain whether scientists will find the remains of the ancient Egyptian queen, there is a good chance we will hear more about this tomb and the mummies buried within it in 2023.

2. Underground city in Turkey

In 2022, archaeologists in Midyat, Turkey, discovered an underground city that dates back 2,000 years and may have been home to up to 70,000 people. The remains of a Christian church and Jewish synagogue have been found, and it's possible that people in the underground city were trying to hide from the Roman Empire, which ruled the area and at times persecuted Christians and Jews. 

One important detail is that only 5% of the city has been excavated so far. Research is ongoing, so it's possible that new discoveries will be made in this underground city in 2023.

3. Repatriated artifacts, possibly even the Elgin Marbles

Museums around the world are going through a reckoning; some institutions are accessing their collections and deciding whether certain artifacts should be returned to their culture or country of origin. For instance, intricate metal sculptures known as the Benin Bronzes were looted from the kingdom of Benin (present-day southwest Nigeria) when the British attacked in 1897. Many of those bronzes are now in museums around Europe, the United States and New Zealand, according to The Art Newspaper. However, Germany returned 21 of the Benin Bronzes to Nigeria in December 2022, The Guardian reported, and the University of Cambridge in the U.K. announced in December that it would return 116 of its Benin Bronzes to Nigeria, the BBC reported. In another case, the National Museum of Scotland plans to repatriate a looted totem pole to the Nisga'a Nation of British Columbia, Canada, The Art Newspaper reported.

In addition, there are talks underway for the British Museum to return the Parthenon Marbles, also known as the Elgin Marbles, to Greece. British law stipulates that the British Museum cannot transfer ownership of its artifacts, but a workaround could be to share the marbles with Greece while putting on a new show of Greek artifacts in the marbles' place.

4. Ukraine's heritage

The ongoing Russian invasion of Ukraine has resulted in the theft, damage and destruction of numerous heritage structures and artifacts. As of Dec. 12, UNESCO has verified damage to 227 heritage sites, including museums, religious buildings and libraries. There has also been extensive looting. For instance, Russian authorities looted gold Scythian artifacts from a museum in Russian-occupied Melitopol. 

Over the past few months, Ukraine's military has been retaking territory and even liberated Kherson, a major city that had been occupied by Russia. As Ukraine retakes more territory, we will likely hear more about damaged, stolen and looted artifacts and archaeological sites. It's also possible that some of the artifacts stolen by Russian soldiers will appear for sale online.

5. New ancient finds along the U.K.'s new railway

For the past few years, archaeologists in the United Kingdom have found remarkable artifacts dating to Roman Britain and Anglo-Saxon England as they survey land ahead of construction of High Speed 2 (HS2), a high-speed railway line that will run from London to the West Midlands. This year alone, archaeologists have discovered several ancient sites, including the well-preserved remains of an Iron Age village that transformed into a bustling ancient Roman town in South Northamptonshire, England; a burial ground for rich pagans dating to around the time of the Anglo-Saxon invasion of Britain in the fifth century A.D.; and an "exquisite" wooden figurine dating to early Roman Britain.

Phase one of the HS2 project is expected to open between 2029 and 2033, so there's still plenty of time to uncover ancient treasures.

Recent reports of unidentified aerial phenomena (UAP) flying through the skies of Ukraine have been officially discredited by Ukraine's national science agency, citing "significant errors" in the report's methods and results.

The report, released in mid-September by scientists at Kyiv's Main Astronomical Observatory (MAO), described "a significant number of objects whose nature is not clear," including multiple so-called "phantoms" which appeared completely black against the sky and seemed to zip through the atmosphere at up to 33,000 mph (53,000 km/h) — roughly twice as fast as an intercontinental ballistic missile.

The report's authors described these phantom objects as UAP — the scientific community's preferred name for unidentified flying objects, or UFOs — but made no attempts to exclude more obvious explanations, such as satellites, drones or artillery used in the ongoing Russian invasion of Ukraine, which began roughly half a year before the report's release.

Related: 9 Things we learned about aliens in 2021

Now, the National Academy of Sciences of Ukraine (NASU) has concluded an investigation into the UAP report, and officially discredited it as unprofessional and lacking scientific rigor.

"The processing and interpretation of results were performed at an inappropriate scientific level and with significant errors in determining distances to the observed objects," a panel of NASU scientists wrote in a statement. The team added that the report "did not meet the professional requirements for publication of the results of scientific research," and ordered that the NASU's name be removed from the document.

Where's the fire?

In their report, the MAO researchers analyzed observations of strange, fast-moving objects detected by one of two observatories near Kyiv. The team inferred the distance, size and speed of these objects based on how much background light each one appeared to be blocking, concluding that many of the mysterious objects were roughly the size of an airplane but moved through the atmosphere with the speed of a spacecraft.

However, by looking only at data from a single telescope, the researchers seem to have inaccurately predicted the distances and locations of those objects — and therefore misjudged the size and speed of the objects, as well, according to work by  Avi Loeb, an astrophysicist at Harvard University who recently published a critical paper on the Ukraine UAP report to the pre-print database, arXiv.org. (The work has not yet been peer-reviewed.)

"The correct method to infer distances is called triangulation, where you observe the same object from different directions," Loeb told Live Science. "But they don't have that data."

If the phantom objects were indeed as large, as fast and as high in the sky as the Ukrainian team suggested, then each object would "produce a giant fireball," like a rocket or meteor does when passing through the atmosphere, Loeb said. The fact that these objects were totally black does not so much prove that they were otherworldly technology, but rather suggests that the astronomers severely miscalculated the objects' respective locations, Loeb added.

Aliens, bombs, or bugs?

In his critique of the UAP report, Loeb suggested that the Ukrainian researchers likely miscalculated the distances to the phantom objects by a factor of 10; if the phantoms were 10 times closer to the camera than the researchers claimed, then the objects suddenly matched the size and speed of artillery shells — a common projectile found in war zones such as Ukraine. Move the objects another 10 times closer to the camera and they could reasonably be interpreted as bullets.

"If you bring it even closer, it could be insects — like a fly moving at a high speed near the telescope, and it would appear dark," Loeb added.

NASU appears to have reached a similar conclusion in their investigation of the UAP report, noting that the astronomers not only made "significant errors" in determining the objects' distances, but also failed to exclude more obvious explanations for the sightings.

"The authors do not provide arguments that natural phenomena or artificial objects of earthly origin may be among the observed UAPs," the NASU scientists wrote in their statement.

While it's unclear exactly what the Ukrainian astronomers observed — be it artillery, bullets, bugs or something else entirely — the impact of Russia's invasion of the country should not be ignored.

According to a 2021 report from the U.S. Office of the Director of National Intelligence (ODNI), it's likely that at least some UAP observed by American military personnel are "technologies deployed by China, Russia, another nation, or a non-governmental entity." 

Other possible explanations for UAP include "airborne clutter," such as birds and balloons; atmospheric phenomena, such as ice crystals; or classified government projects, according to the ODNI report

The report does not mention aliens as a possible explanation. However, the U.S. government is not ready to exclude this possibility for sightings in U.S. airspace. Earlier this year, the U.S. Congress approved funding for the Department of Defense to open a new office focused exclusively on managing reports of UFO sightings by the U.S. military. If the truth is out there, perhaps the government will find it.

Near-black frogs far outnumber their highlighter-yellow fellows in Chernobyl's radiation-blasted ecosystems, in a direct example of "evolution in action," a new study shows. The study, published Aug. 29 in the journal Evolutionary Applications, found that eastern tree frogs (Hyla orientalis) with more skin-darkening melanin pigment were more likely to survive the 1986 nuclear accident in Ukraine than frogs with lighter skin, leading to populations today that are dominated by darker frogs.

"Radiation can damage the genetic material of living organisms and generate undesirable mutations," researchers wrote in a post on The Conversation about their research. "However, one of the most interesting research topics in Chernobyl is trying to detect if some species are actually adapting to live with radiation. As with other pollutants, radiation could be a very strong selective factor, favoring organisms with mechanisms that increase their survival in areas contaminated with radioactive substances."

On April 26, 1986, a reactor at the Chernobyl nuclear power plant in Ukraine exploded, spewing radioactive materials across an 18-mile (30 kilometers) radius. 

"The Chernobyl accident released approximately 100 times the energy released by the nuclear bombs of Hiroshima and Nagasaki," Pablo Burraco, the study's lead author and a biologist with the Doñana Biological Station in Seville, Spain, told Live Science in an email.

Related: Frogs' skulls are more bizarre (and beautiful) than you ever imagined

Officials evacuated residents from the contaminated zone following the disaster and established a 1,040 square-mile (2,700 square kilometers) exclusion zone. In the decades since, the abandoned area has become a wildlife refuge. Burraco and his team wanted to understand how the nuclear meltdown drove evolution in the animals living there.

After studying more than 200 male frogs whose habitats were spread across 12 different breeding ponds throughout the radioactive contamination zone, researchers found that "on average, 44% were darker than those outside of Chernobyl," Burraco said. "We consider the most plausible explanation to [why] frogs within the Chernobyl Exclusion Zone [are changing color] is that the extremely high radiation levels at the moment of the accident selected for frogs with dark skin."

Why dark skin? It turns out that high melanin levels in frogs’ skin shielded them from radiation. 

"Melanin is known to protect against radiation because it can mechanically avoid the production of free radicals caused by the direct impact of the radioactive particles on cells," Burraco said. "Radiation can induce oxidative stress and damage essential structures for life such as the membrane of cells or even DNA."

Cells in the lighter frogs were bombarded with higher levels of damaging radiation, which killed them off at higher rates than their darker counterparts. After the blast, dark frogs had a higher likelihood of surviving, the study concluded. 

Researchers also looked for potential negative effects of excess melanin on the post-Chernobyl dark frogs. They found that like in other species, including certain types of fungi, having darker pigmented skin didn't harm the overall health of the amphibians and actually helped ionize radiation, which prevents ionized molecules from getting into cells and damaging them.

"The production of melanin can be metabolically costly, this has been described, for example, in several bird species," Burraco said. "However, in frogs, the main melanin pigment is called eumelanin and its production seems not to incur in physiological costs."

The skies over Kyiv are swarming with unidentified flying objects (UFOs), according to a new report from the Main Astronomical Observatory of the National Academy of Sciences of Ukraine. 

Of course, given that Russia and Ukraine have been locked in a months-long war that relies heavily on aircraft and drones, it's likely that many of these so-called UFOs are military tools that appear too fleetingly to identify, a U.S. intelligence agency has speculated.

Published to the preprint database arXiv, the report — which has not yet been peer-reviewed — describes recent steps that Ukrainian astronomers have taken to monitor fast-moving, low-visibility objects in the daytime sky over Kyiv and the surrounding villages. Using specially calibrated cameras at two weather stations in Kyiv and Vinarivka, a village about 75 miles (120 kilometers) to the south, astronomers observed dozens of objects "that cannot scientifically be identified as known natural phenomena," the report said.

Government agencies tend to refer to such objects as UAP, short for  "unidentified aerial phenomena."

"We observe a significant number of objects whose nature is not clear," the team wrote. "We see them everywhere."

The researchers divided their UAP observations into two categories: "cosmics" and "phantoms." According to the report, cosmics are luminous objects that are brighter than the background sky. These objects are designated with birds' names — such as "swift," "falcon" and "eagle" — and have been observed flying solo as well as in "squadrons," the team wrote.

Phantoms, by contrast, are dark objects, usually appearing "completely black," as if absorbing all light falling onto them, the team added. By comparing observations from the two participating observatories, the researchers estimated that phantoms range from 10 to 40 feet (3 to 12 meters) wide and can travel at speeds of up to 33,000 mph (53,000 km/h). For comparison, an intercontinental ballistic missile can reach speeds of up to 15,000 mph (24,000 km/h), according to The Center for Arms Control and Non-Proliferation.

The researchers did not speculate as to what these UFOs may be. Rather, their paper focuses on the methods and calculations used to detect the objects. However, according to a 2021 report from the U.S. Office of the Director of National Intelligence (ODNI), it's likely that at least some UAP are "technologies deployed by China, Russia, another nation, or a non-governmental entity." 

Given the ongoing Russian invasion of Ukraine, which began in February 2022, it's reasonable to suspect that some UAP described in the new report may be linked to foreign surveillance or military technologies.

According to the ODNI report, other possible explanations for UAP include "airborne clutter," such as birds and balloons; atmospheric phenomena, such as ice crystals; or classified government projects. Neither the U.S. nor Ukraine reports raise the possibility of extraterrestrial visitors.

The U.S. government has openly renewed its interest in UAP investigations since 2017, when several videos taken by U.S. Navy aircraft leaked to the media. The now-infamous videos showed unidentified aircraft moving in seemingly impossible ways, with no explanation.

The government subsequently declassified the footage and recently revealed that more military footage of UAP encounters does exist, though the Department of Defense (DOD) will not be releasing them due to "national security concerns." Earlier this year, Congress approved funding for the DOD to open a new office focused exclusively on managing reports of UFO sightings by the U.S. military. The authors of the new UAP report out of Ukraine added that the country's National Academy of Science is interested in contributing to this ongoing research.

Originally published on Live Science.

Archaeologists in Ukraine recently uncovered a glut of arrowheads, spinning wheels and ceramic fragments that date to the late sixth century and early fifth century B.C., a time when Scythian nomads, renowned for their skill as mounted archers, occupied the area. 

The Scythians were a culturally related group of nomadic tribes that occupied large regions of grassland between China and the northern coast of the Black Sea from about 800 B.C. to 300 A.D. The fifth-century B.C. Greek historian Herodotus claimed that all Scythians descended from the hero Heracles and a creature that was half-woman and half-snake, with whom Heracles had a son named Scythes. However, modern archaeological and genetic analyses suggest that the Scythians actually emerged from various Siberian, East Asian and Yamnaya Eurasian groups, and that the tribes were ethnically diverse.

Remnants of Scythian culture can be found at the Bilsk Historical and Cultural Reserve near the village of Bilsk in the Poltava province of central Ukraine. There, between the rivers Vorskla and Sukha Hrunia, lay the remains of a 12,300-acre (5,000 hectare) settlement from which a wealth of artifacts have been excavated in recent decades, according to Ukraїner, a media project aimed at sharing cultural stories of Ukraine. 

Human-made earthen ramparts can still be found at the fortified settlement, which many scholars associate with the ancient city of Gelonus, an important trading hub that Herodotus described in his writings.

Related: Did the Amazon female warriors from Greek mythology really exist? 

In the current excavations, archaeologists exploring the reserve discovered 40 objects that date to the Scythian period, including fragments of locally-made Scythian ceramics and Greek tableware likely made in ancient Attica and Olbia, according to an Aug. 21 statement by Ukrinform, Ukraine's state information and news agency. The team also uncovered grain and garbage pits, as well as evidence of "various economic buildings," the statement notes.

The team has not uncovered any ancient dwellings in the area, as "probably, they were destroyed during the development of a quarry that operated in this area in the past years," Ihor Korost, director of the Bilsk Historical and Cultural Reserve, told Ukrinform. 

However, the archaeologists did discover the remains of a Late Bronze Age dwelling that measured about 76 square yards (64 square meters) at a nearby site; this dwelling predates the Scythian artifacts and buildings. 

"Just imagine, it is more than 3,300 years old!" Korost told Ukrinform of the dwelling. "Further research of the site will make it possible to determine its exact age, establish the stages of development, and features of settlement."

Originally published on Live Science. 

Acts of genocide — trying to partially or completely destroy an entire people or group — have been committed countless times in prehistory, and numerous times since. For example, Egyptian hieroglyphs on a memorial stone from the late 13th century B.C. give what may be the earliest-known mention of the people of Israel, along with the erroneous claim that the pharaoh Merneptah killed them all; and in 88 B.C. Mithridates, the king of Pontus, ordered all Italians in his lands killed, resulting in perhaps 100,000 murders and the brutal Mithridatic Wars with Rome. Many times the Romans also committed genocide against their enemies: During the destruction of Carthage in modern-day Tunisia in 146 B.C., for example, an estimated 62,000 people were executed and 50,000 enslaved; and in the Gallic Wars of the first century B.C., Julius Caesar claimed that his armies killed more than a million Gauls and Germans (historians now think the real number was much lower). Many millions are also thought to have died in colonial genocides at the hands of European powers, especially in the New World and in Africa.

However, genocide has only been internationally recognized and become a major world concern in the last 80 years, alongside the industrialization of warfare and the large-scale atrocities that occurred in the 20th century. The term genocide is now almost defined by the Holocaust and other mass killings during World War II, when six million Jews and about 12 million others — including Romani, Russians, and Poles — were murdered during the Nazi German occupation of Europe. 

The concept of genocide originated in the 1920s, as a way to describe the Armenian genocide committed by the Ottoman Empire from 1915 to 1916, which may have killed more than 1 million people, according to Britannica. And new reports of genocide have marred every decade since, from the communist mass killings in Russia since 1918 and in China after 1949; to the wars in former Yugoslavia in the 1990s, the massacres in Rwanda in 1994, and the killings in Sudan that have been ongoing for most of the 21st century.

What is genocide?

The word "genocide" was coined by Raphael Lemkin, a Polish-Jewish international lawyer who in the late 1920s read about the massacres and other brutalities perpetrated on Armenian Christians by the "Three Pashas" government of the Ottoman Empire's nationalist "Young Turks" movement. Lemkin discovered that no laws existed to try the Young Turks leaders for their crimes. During World War II, Lemkin escaped Poland following the invasion by Nazi Germany and the Soviet Union, and he lectured in Sweden; but 49 of his relatives — all Jewish — were killed during the Holocaust. In 1944, after emigrating to the United States, he wrote the book "Axis Rule in Occupied Europe," a legal review of the Nazi occupation, in which he introduced the word genocide. The Greek prefix "genos" means "race" or "tribe," while the Latin suffix "cide" translates to "killing," according to the United Nations.

"His idea came out of his horror at the Armenian Genocide, and then he saw it being done again in the Holocaust," said Gregory Stanton, a former U.S. State Department diplomat, former professor of genocide studies at George Mason University at Arlington, Virginia, and the founder of the nonprofit group Genocide Watch. "[Lemkin] realized that international law was totally inadequate to deal with this problem; there needed to be a whole new name for it, and there needed to be a convention, an international treaty."

Lemkin's concept of genocide as a crime under international law was a basis of the Nuremberg trials — a series of trials of former Nazi leaders in 1945 and 1946 conducted by an international tribunal of Allied countries and representatives of former Nazi-occupied countries; and his campaigning led to the establishment of the United Nations' Genocide Convention, a treaty that made genocide an international crime in 1951. The treaty defines genocide as "any act committed with intent to destroy, in whole or in part, a national, ethnic, racial, or religious group." 

The convention lists examples of genocidal crimes, including: killing members of a group; causing them serious bodily or mental harm; inflicting conditions calculated to bring about a group's physical destruction; imposing measures to prevent births in a group; and forcibly taking their children from them to be raised elsewhere. The Genocide Convention is the definition of genocide used by intergovernmental bodies such as the International Criminal Court at The Hague in the Netherlands.

Critically, Stanton said, the international agreements against genocide don't include the persecutions and killings of people for their political beliefs or membership of an economic, social or cultural group, although these have been a feature of many genocides throughout history. "The aim [of genocide] is to destroy a group," he said. But the major nations at the UN, including the U.K., the U.S., Russia and France, didn't want such a broad definition: "These powers realized that if these things were in there, they'd all be guilty," Stanton said.

Communist killings

According to Stanton, when the convention was first agreed, Joseph Stalin, the leader of the Soviet Union at the time, was one of the biggest opponents to a broader definition of genocide, probably because tens of millions of his perceived political opponents had been killed since the imposition of communism in Russia in 1917, and tens of millions more would die before the Soviet Union collapsed in 1991; a 1990 study by the American political scientist Rudolph Rummel estimated that more than 61 million people were murdered by the Soviet Union. "The Soviet Union probably killed more people than any other entity, except possibly Communist China," Stanton said; Rummel's 1990 study suggested that up to 102 million people had been killed by Chinese communists.

No leaders of the Soviet Union or China have ever been put on trial for genocide, but Stanton said that rulers and officials from other countries have been prosecuted under the existing laws. For example, from 1975 to 1979 the communist Khmer Rouge movement, led by Pol Pot, ruled much of Cambodia and murdered between 1.5 and 3 million people, according to the University of Minnesota. Many decades later, from 1997 to 2012, two of the surviving Khmer Rouge leaders were tried and found guilty of war crimes by a joint United Nations and Cambodian tribunal; the crimes included genocide based on Khmer Rouge persecutions of Cambodian ethnic groups, such as the Cham and ethnic Vietnamese, Chinese and Thais.

Communists have also been the victims of genocide. According to a case study at Yale University, more than 400,000 people were killed during the Indonesian genocide in 1965 and 1966, in which the Western-aligned government targeted Communist Party members and sympathizers, as well as ethnic and religious groups. And during a civil war from the 1960s to the 1990s, the Guatemalan government persecuted ethnically Maya people for their presumed support of communist guerrillas; up to 200,000 people were murdered, according to the Holocaust Museum Houston.

Ethnic violence

People across the world have committed genocide due to ethnic differences. A study published in 2015 in the journal The American Historical Review suggested that the U.S. caused the deaths of more than 4 million Native Americans before 1900. The U.S. has also been accused of genocide against Black Americans, according to a study by University of Washington historian Susan Glenn. The term genocide has also been used to describe the persecutions and mass killings of Indigenous ethnic groups in Central and South America, including in Mexico, Peru, Paraguay, Chile and Argentina.

Massacres of ethnic groups were also committed in Europe during the breakup of Yugoslavia and its aftermath in the 1990s. The Holocaust Museum Houston estimates that Bosnian Serbs murdered tens of thousands of Muslims and Croats in acts of genocide, some of which were euphemistically called "ethnic cleansing." The total includes the victims of the Srebrenica massacre in July 1995, when Bosnian Serb forces killed as many as 8,000 Bosnian Muslim men and boys — the worst massacre in Europe since the Holocaust. 

In Rwanda in central Africa, Hutu extremists murdered an estimated 800,000 people and raped hundreds of thousands of women, most of whom were from the country's ethnic Tutsi minority, over 100 days in 1994. Ethnic differences have also played a role in Sudan's Darfur genocide, where it's estimated the Sudanese government has caused the deaths of more than 200,000 people, while millions of people have been driven from their homes. The conflict has been called the first genocide of the 21st century and is still ongoing.

Recent genocides

Accusations of genocide have been levelled at Russia since its invasion of Ukraine in February 2022. According to Stanton, although Russians and Ukrainians share common origins, they are now different national groups and also different ethnic groups because their languages are slightly different. "Genocide is the intentional destruction, in part, of a national group — and the Ukrainians are definitely a national group," he said. The situation in Ukraine is complicated by memories of the Holodomor, also known as the "Great Famine" — a human-made famine that in 1932 and 1933 killed up to 5 million people throughout the Soviet Union, including Ukraine. Its effects were worsened in Ukraine by harsh political decrees, and it's estimated that at least 3.9 million Ukrainians died there between those years, according to Britannica. The Holodomor is now widely recognized as a genocide committed by the Soviet Union against the Ukrainians.

Stanton also regards the persecution since 2014 of ethnic Uyghurs in China's far west Xinjiang province as an ongoing genocide. BBC News reported in 2021 that an unofficial U.K.-based tribunal determined that the sterilizations and birth control measure forced on Uyghurs by the Chinese government were acts of genocide, although no mass killings of Uyghurs were known to have taken place. The tribunal in London heard from more than 70 witnesses and determined that China had detained or imprisoned more than 1 million Uyghurs and other Muslims in Xinyang, while former detainees alleged torture, forced sterilizations and sexual abuse. 

China has denied the accusations, however, calling them politically motivated. But Stanton is not persuaded: The Chinese government "has violated every single one of those acts of genocide," he said. "China is trying to wipe out their [the Uyghurs'] culture."

Future genocides

Experts warn that there are more genocides to come. Stanton is especially concerned about some parts of India, where political, ethnic and religious tensions threaten to break out into mass violence; and parts of West Africa, where countries such as Nigeria, Burkina Faso and Mali are experiencing Islamist insurgencies led by ethnic Fulanis, who mainly target Christian civilians with almost daily killings, kidnappings and rapes, according to a 2017 study in the journal CTC Sentinel. 

Stanton said that by studying telltale aspects of a society, it's now possible to identify potential genocides before they happen. The nonprofit group Genocide Watch lists 10 stages of a genocide, including elements like the separate classification within a country of distinct ethnic, racial, religious or national groups; legal and social discrimination against those groups; efforts to dehumanize them, perhaps by attaching negative names or through hate speech; and the organization, polarization and preparation of genocidal groups, perhaps leading to the persecution and attempts to kill people . The last stage Genocide Watch lists is denial, when the perpetrators of genocide pretend it never happened.

But Stanton said it's often difficult to persuade political leaders to act in response to the signs of an impending genocide. "How do you engage the consciousness and the will of policymakers to act on these warnings, to actually do something to stop the process?" he said. "That is something I don't think we've really solved yet."

Additional resources

• Take a free online course at Coursera on "Introduction to International Criminal Law," which includes a dive into the Nuremberg trials with Michael Scharf, a professor at the Law School of Law at Case Western Reserve University in Ohio.
• Or see how the United Nations describes genocide.
• You can also read about genocide's history at Cornell Law School.

Originally published on Live Science.

Haunting scenes of the death, destruction and sickness that followed the Chernobyl meltdown 36 years ago — the deadliest nuclear accident of all time — were recorded on film and video but remained hidden for decades. Now, these previously unknown stories are finally coming to light, in a new HBO documentary, "Chernobyl: The Lost Tapes."

A trailer for the film, which HBO shared Friday (June 3) on YouTube, offers a glimpse of what unfolded in Ukraine (then a part of the Soviet Union, or USSR) after the horrific disaster, which took place on April 26, 1986 in the nuclear power plant at Chernobyl, about 81 miles (130 kilometers) north of Kyiv, the Ukrainian capital. 

In the long-lost tapes, testimony from witnesses offer a glimpse of life in Chernobyl before the disaster, and show how it was forever transformed in the accident's aftermath. "Everything was documented," one of the witnesses says in the trailer, but many of the explosion's details and potential dangers were obscured by Soviet officials, who sent in soldiers to "liquidate" the damage and to help cover up the incident, HBO representatives said in a statement. 

Related: 5 weird things you didn't know about Chernobyl

People who lived in Chernobyl and nearby, as well as the workers who were assigned to clean up the damage at the site, were subsequently kept in the dark about the risks posed to their health by exposure to deadly radiation. As more people who had been exposed to Chernobyl's radiation fell sick, their trust in Soviet leadership eroded, contributing to the widespread unrest that ultimately dissolved the Soviet Union, according to the statement.

Chernobyl's reactor explosion killed two plant workers, and 29 more people, many of them firefighters who rushed to battle the blaze, later died from radiation poisoning, according to the International Atomic Energy Agency. Over the years that followed, cancer rates skyrocketed among Ukrainian children, climbing by about 90%, Live Science previously reported. In 2006, a report commissioned by Greenpeace International estimated that over 93,000 people in Ukraine, Belarus and Russia died from illnesses linked to radiation exposure from Chernobyl. 

The report further stated that approximately 270,000 people in those countries who developed cancers, would not have done so had they not been exposed to the high levels of radiation produced by the accident.

"Chernobyl: The Lost Tapes" premieres June 22 on HBO at 9 p.m. ET/PT, and will be available to stream on HBO Max.

Originally published on Live Science.

Russian soldiers have reportedly stolen gold Scythian artifacts dating back about 2,300 years from the Melitopol Museum of Local History in Ukraine. Additionally, there are reports that a museum staff member is currently being held by the Russian military.

The Scythians, culturally related groups of nomadic pastoralists and formidable warriors, thrived across Eurasia between roughly 800 B.C. and A.D. 300 and crafted many beautiful artifacts out of gold.

Melitopol, located in southeastern Ukraine, has been occupied by the Russian military since March 1, according to news reports. Since the Russians started their invasion of Ukraine on Feb. 24, they have captured large swaths of territory in the eastern and southern parts of the country. However, their attempts to take the capital city of Kyiv have failed.

The Russians "have taken hold of our Scythian gold. This is one of the largest and most expensive collections in Ukraine, and today we don't know where they took it…," said Ivan Fedorov, the mayor of Melitopol during a national telethon, according to the news site Ukrinform. Federov was forced out as mayor by the Russian military after they took over the entire city on March 1. 

Related: 2,500-year-old burial mound found in Siberia's 'Valley of the Kings'

Leila Ibrahimova, the director of the museum, confirmed the theft in an interview with the New York Times. The artifacts stolen included at least 198 gold items, including ornaments in the form of flowers and gold plates, Ibrahimova told The New York Times, noting that some of the gold items were made by ancient Greeks and were sent, either as gifts or through trade, to the Scythians. Additionally, the Russian troops took 300-year-old silver coins as well as "old" weapons and medals. 

Ibrahimova said that she was held captive before the Russians released her in mid-March. Additionally, another museum employee named Galina Andriivna Kucher was abducted on April 30 after she refused to give information about the rest of the museum's Sycthian collection, which the curators had hidden, Eskender Bariiev, a Ukrainian activist, wrote on his Facebook page.  

Live Science has not been able to reach Ibrahimova or confirm the abduction of Kucher. Archaeologists that Live Science reached said that the Melitopol area was an important hub for Scythian activity around 2,000 years ago. 

"Melitopol is well known in archaeology thanks to a Scythian era burial ground nearby," Caspar Meyer, a professor at the Bard Graduate Center in New York City, a research institute that is dedicated to the study of material culture, told Live Science in an email. "One of the mounded tombs [near Melitopol] excavated in 1954 by the archaeologist A. I. Terenozhkin contained a rich subterranean tomb with thousands of artifacts in gold and other metals, which are mostly in the Kiev museum." 

Other archaeologists confirmed that many of the finest Scythian artifacts found in the Melitopol area are in the Kiev Museum. "All the best of the Scythian gold from Ukraine, other than that taken to St. Petersburg in the nineteenth century, is collected together in the Kiev Museum of Historical Treasures [of Ukraine], where I assume it is in safe hands," Barry Cunliffe, an emeritus professor of European archaeology at the University of Oxford, told Live Science in an email. 

Cunliffe emphasized that many important Scythian burial sites lie in conflict areas within Ukraine and are in danger of being looted.

What will happen to the stolen artifacts?

It's unclear what the Russian soldiers will do with the stolen artifacts. It's possible that they could be sold or they could be displayed in institutions in Russia or territories that they occupy, Sam Hardy, an expert in the trafficking of cultural properties, told Live Science in an email. 

"There are Ukrainian archaeologists, museologists and art historians who are doing as much as humanly possible to track what is happening" said Hardy, noting that the demands of the war (many heritage professionals are performing military duties) and lack of funding make it difficult to track looted antiquities. 

Originally published on Live Science.

Sometime during Russia's invasion of Chernobyl in Ukraine, looters stole radioactive material from a radiation monitoring laboratory near the defunct nuclear power plant. There seems to be a low risk that this material would be used in so-called dirty bombs, an expert told Live Science. 

The looters took pieces of radioactive waste, which could theoretically be used to create a dirty bomb, a device that combines radioactive material with a conventional explosive, Anatolii Nosovskyi, director of the Institute for Safety Problems of Nuclear Power Plants (ISPNPP) in Kyiv, told Science. They also swiped radioactive isotopes — radioactive chemical elements with different numbers of neutrons in their nuclei — that are usually used to calibrate instruments in the monitoring lab, Nosovskyi said.

On March 25, Science reported that the radioactive material had been stolen. New Scientist later confirmed these reports with an ISPNPP scientist, who spoke with reporters on the condition of anonymity. The source said that the earlier Science report was "accurate based on the information available." 

The stolen material can't be used to make nuclear weapons, as it doesn't contain any plutonium or uranium, Bruno Merk, a research chair in computational modeling for nuclear engineering at the University of Liverpool, told New Scientist.

Related: What would happen if Russia bombed Chernobyl? 

"There are so many radioactive sources around the world. If someone wants to get their hands on this there's an easier way," Merk said. "These radioactive sources you can steal in every hospital. It would always have been possible for someone to sneak in and steal something. I don't see that the risk is any higher than before the Russians invaded."

Although its not useful for making nuclear weaopns, some of the stolen material could be of very limited use in the construction of a dirty bombs, Merk told New Scientist.

"Calibration sources" — meaning the isotopes — "typically have very small quantities of radioactive materials," Edwin Lyman, a physicist and the Director of Nuclear Power Safety with the Union of Concerned Scientists, told Live Science in an email.

If the stolen waste materials were highly radioactive, they would need to be stored and transported in heavy shielding, to protect the handlers from radiation injury. Because of this, "I suspect the stolen samples are also small quantities," he said.

"I'm skeptical that there would be any strategic purpose for Russia to use these materials in a dirty bomb," Lyman told Live Science. Such a bomb could spew radioactive material over a localized area, but it would be unlikely to cause many immediate severe health effects. That said, the extent and severity of the potential damage would depend on the size and other characteristics of the materials in question, he noted. 

In general, dirty bombs, also known as "radiological dispersal devices" (RDDs), do not release enough radiation to kill people or cause severe illness, according to the U.S. Nuclear Regulatory Commission. Those closest to the bomb when its detonated would be the most likely to be injured by the explosion itself, while the resulting radiation could be dispersed within a few blocks or miles from explosion site. 

"As radioactive material spreads, it becomes less concentrated and less harmful," the Commission notes. "Immediate health effects from exposure to the low radiation levels expected from an RDD would likely be minimal."

"It's unlikely that such a bomb could cause death, destruction and terror anywhere near the scale of Russia's bombardment of civilian areas with conventional weapons," Lyman said. "Although the presence of radioactive contamination could add another element of fear to an already frightful situation."

Originally published on Live Science.

In All About History issue 115, on sale now, discover how Stalin secured his grip as the dictator of the Soviet Union using a series of purges that locked up or murdered his greatest political enemies. How did the Great Terror begin? Who were its agents? Who were the victims? We look to answer all of these questions and more.

Peter Whitewood, author of "The Red Army and the Great Terror: Stalin’s Purge of the Soviet Military" (University Press of Kansas, 2015) is your guide to one of the darkest chapters in the history of Russia, taking you from the mysterious murder that kickstarted the process to the gulags where many political prisoners ended up.

Also in All About History 115, uncover the story of the killer queen of Kyiv, Saint Olga, and how she took revenge for the murder of her husband. You can also read about the origins of the UFO panic in the 1950s and what history has to teach us about how pandemics start and how they end. 

Related: Read a free issues of All About History

You can also learn all about the history of coffee, how women were erased from the Bible, about the life of Miguel Hidalgo the 'father of Mexico' and much more.

Stalin's purges: Inside the Great Terror

On 1 December 1934, former member of the Soviet Communist Party Leonid Nikolaev entered the party’s headquarters, the Smolny Building, in the city of Leningrad. After making his way to the third floor, he gunned down Leningrad party boss Sergei Kirov outside his office. 

Kirov was killed instantly, murdered in the middle of the afternoon. Nikolaev was immediately arrested, and confusion quickly abounded in the Soviet press as the Soviet political police, the NKVD, launched a search for other suspected accomplices. 

Before the shooting, Nikolaev had become increasingly resentful of the party and blamed it for his unemployment and worsening personal circumstances. He had grown steadily convinced, moreover, that his wife was having an affair with Kirov.

Nikolaev’s motives aside, the impact of the shooting in the following months and years proved sensational and was the chief starting point of Soviet leader Joseph Stalin’s Great Terror. Before this dramatic day, Nikolaev was by no means a significant person in Leningrad. But his actions on 1 December had far-reaching consequences for hundreds of thousands of Soviet people living under the Stalin regime in the late 1930s.

Read more in All About History 115.

Olga of Kyiv's revenge

Grand Princess Olga ruled Kyivan Rus as regent for her son Sviatoslav during a time when outsiders actively sought to control the rapidly expanding trade-rich kingdom. She effectively used her armies and battle-maiden acumen to defend the realm against rebelling tribes, the Byzantine emperor and the nomadic Pechenegs, giving her son a state significantly stronger than the one she was unexpectedly charged with decades earlier. 

Near the end of her reign, Olga converted to Christianity, the first member of the Riurikid Dynasty to do so, thus encouraging the religion’s spread among the pagan Slavs, Finns and Scandinavians of the realm. 

For this, Olga was sainted in the Eastern Orthodox Church, the first of a long line of Riurikid warrior saints that gave the state and its princes a growing line of pious warmongering role models to follow as they governed northern Eurasia for 700 years. It is difficult to exaggerate Olga’s importance to the history of Eastern Europe.

Learn more about Olga and how she defended her family and her kingdom in All About History 115.   

How America became obsessed with flying saucers

“Keep looking, keep watching the skies!” Douglas Spencer proclaims during the final moments of the 1951 sci-fi horror film "The Thing From Another World." From 1947 onwards that’s just what America was doing as the nation became gripped by a flying saucer frenzy. 

The birth of the UFO phenomenon is one of the most intriguing moments in late 1940s and ’50s popular culture. During this period some of the most infamous UFO sightings of the 20th century occurred, and places like Roswell became synonymous with visitors from other planets and sinister conspiracies. But as the world entered one of the hottest phases of the Cold War, just why was America obsessed with “watching the skies”?

As far as historians have been able to tell, the beginning of the flying saucer craze can be traced back to events that occurred on 24 June 1947 when businessman and amateur aviator Kenneth Arnold witnessed something strange in the airspace above Mineral, Washington.

Read the rest of this fascinating story in All About History 115.

Russian forces bombed and destroyed a hospital complex – including a 600-bed maternity hospital and a children's ward – in the Ukrainian city of Mariupol on Wednesday (March 9), according to Ukrainian officials.

At least 17 civilians have been reported injured in the bombing, while further details about potential casualties are "being clarified," according to CNN. Video of the building after being bombed shows the interior of the hospital in shambles, with windows blown out, walls riddled with holes and hallways strewn with mangled hospital beds and debris.

According to Ukrainian President Volodymyr Zelenskyy, hospital patients and children remain trapped under the wreckage.

"Direct strike of Russian troops at the maternity hospital. People, children are under the wreckage," Zelenskyy said on Twitter, adding that the attack was an "atrocity."

The bombing occurred despite an agreed ceasefire that was put in place on Saturday (March 5) to allow thousands of citizens to escape Mariupol. The coastal city of more than 400,000 people has been bombarded with shells "continuously" since Russian forces surrounded the city a week ago, deputy mayor Sergiy Orlov told The Guardian and other foreign media in a call on Wednesday.

According to Orlov, the city has spent the last eight days without heat, power, gas or electricity, after Russian tanks destroyed all 15 power lines on the outskirts of the city, as well as the city's gas connection. 

The city has been able to evacuate between 2,000 and 3,000 residents per day, using a fleet of municipal buses, Orlov added. The deputy mayor estimates that half of the city's population – 200,000 people – are trying to flee. 

Originally published on Live Science. 

SpaceX's Starlink internet is now active in Ukraine. But will the company be able to keep it online? 

Russia's attacks on Ukraine continue to take lives and destroy infrastructure as the country invades. This infrastructure damage has disrupted internet access in Ukraine, leading a government official to publicly request Starlink satellite internet access for the country from SpaceX CEO Elon Musk. Musk obliged, activating Starlink service in Ukraine and sending additional hardware. But with continued attacks on infrastructure, how will Ukraine stay connected? 

"@elonmusk @SpaceX @SpaceXStarlink many thx! Starlink keeps our cities connected and emergency services saving lives! With Russian attacks on our infra, we need generators to keep Starlinks & life-saving services online — ideas?" Mykhailo Fedorov, Ukraine's vice prime minister and the country's minister of digital transformation, who made the original request of Musk, asked on Twitter today (March 2).

Related: Geomagnetic storm sends 40 SpaceX satellites plummeting to Earth

Fedorov brings up an important point: Even though Starlink operates without the need for traditional internet infrastructure, the Earth-bound hardware still needs power. And, as Russian attacks bombard the country, Ukraine's internet access will continue to be threatened. 

Fedorov's statement publicly reached out for help acquiring generators to keep Starlink online for Ukrainians. But Musk responded with an alternative suggestion.

"Solar panels + battery pack better than generator, as no heat signature or smoke & doesn't run out of fuel," Musk wrote in response on Twitter. 

Fedorov's concern also points to the importance of internet access for the country under attack.

Internet connection enables what Fedorov described as "life-saving" communication, whether that be among family members displaced and separated by a missile attack or first aid teams trying to locate an injured person. Internet access is a critical component for those in Ukraine fighting to survive the invasion.

Editor's note: Fedorov replied to Musk later today, stating:

"Good point - should work even with Ukrainian winters! We will keep you posted as we roll out more Starlinks across the country. THANK YOU again for helping us out with @SpaceXStarlink - this will save a lot of lives."

Russian criticism

Dmitry Rogozin, the director-general of Russia's space agency Roscosmos, has been publicly outspoken on Twitter about the effects of the war on outer space relations. Most recently, Rogozin announced that Roscosmos would halt UK-based internet satellite company OneWeb's launch, planned for Friday (March 4) aboard a Russian Soyuz rocket, if the company and the UK government did not meet certain demands.

Now, Rogozin is speaking out about SpaceX's provision of Starlink service to Ukraine, according to a statement translated and shared by space enthusiast Katya Pavlushchenko.

"When Russia implements its highest national interests on the territory of Ukraine, @elonmusk appears with his Starlink which was previously declared as purely civilian," Rogozin stated, both referring to the invasion as an implementation of national interests as well as referring to the country of Ukraine as a territory.

"I warned about it, but our "muskophiles" said — he is the light of the world [of] cosmonautics. Here, look, he has chosen the side. I don't even blame him personally. This is the West that we should never trust," Rogozin added.

Email Chelsea Gohd at cgohd@space.com or follow her on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.

The Soviet Union was the world's first communist country. It was established following a civil war in Russia that raged from 1917 to 1921. The Soviet Union controlled a vast amount of territory and competed with the United States in a conflict known as the Cold War, which at several moments put the world on the brink of a nuclear war and also drove the Space Race. 

The Soviet Union's full name was the "Union of Soviet Socialist Republics" or U.S.S.R. "Soviet" comes from the name for workers' councils, and the hammer and sickle on its red flag symbolically represented the labor of the country's workers. 

The Soviet Union's influence on the world was huge and still has an impact today. In the decades after the founding of the U.S.S.R., communist governments emerged that still exist now in China, Cuba and North Korea, among other countries. While Russia is no longer communist, its president, Vladimir Putin, considers the fall of the Soviet Union the "greatest geopolitical catastrophe of the 20th century" and is currently (as of February 2022) invading Ukraine, a now-independent country that was part of the Soviet Union. 

Related: Russian culture: Facts, customs & traditions

The Soviet Union collapsed in 1991, following a series of economic and political problems and broke up into 15 independent countries.

Founding of the Soviet Union

Prior to the establishment of the Soviet Union, Russia was a monarchy ruled by a king, or czar. However, czarist Russia was fertile ground for a revolution. The czarist family lived a life of luxury, as illustrated by the ornate Fabergé eggs they commissioned and collected, while much of the population lived in poverty. Around 80% of the population may have been living in rural areas around the year 1900. That being said, recent research indicates that the level of inequality in the country was not particularly unusual — both for the time and compared with today's levels. 

"Russia's income inequality was not exceptional, either in comparison to contemporary societies or when stacked up against estimates for the post-Soviet period. This was despite the extreme suppression of political rights, the inequality of land ownership, and the clear regressivity of the imperial fiscal system," Peter Hindert and Steven Nafziger wrote in a paper published in 2014 in the Journal of Economic History. Hindert is a distinguished research professor of economics at the University of California Davis, and Nafziger is an economics professor at Williams College in Massachusetts. 

In the beginning of the 20th century, czarist Russia suffered a series of military defeats. From 1904 to 1905, Russia lost the Russo-Japanese War against Japan. A substantial amount of Russia's navy was destroyed or captured, and Russia was forced to cede territory to Japan. 

A revolution occurred in Russia in 1905, following the country's defeat to Japan, when parts of Russia's military rebelled against Czar Nicholas II. One famous example is the battleship Potemkin, whose crew mutinied and took over the ship. While the revolution was put down over the next two years by pro-czarist forces, it illustrated the fragile hold the czarist family had over their country. In response, Nicholas II implemented reforms that reduced the Czar's power to some degree. 

The impact of the failed 1905 revolution has been widely debated by commentators and historians, wrote Abraham Ascher, a distinguished professor of history at the City University of New York, in a paper published in the book "The Russian Revolution of 1905: Centenary Perspectives" (Routledge, 2005). Ascher noted that Lenin thought of it as a dress rehearsal for the 1917 revolution. Some historians believe that the revolution actually started in 1904 and ran on for years, whereas other historians don't believe that there was a "revolution" at all in 1905 but rather a series of smaller rebellions, Ascher wrote. 

The situation worsened in 1914 when Russia entered World War I on the side of the Allies — mainly Britain, France, Japan, and later Italy and the U.S. — against the Central Powers — mainly Germany, the Austro-Hungarian Empire and the Ottoman Empire. The Russians lost several battles against Germany, and German forces advanced deep into the Russian Empire, coming close to St. Petersburg (the then-capital of Russia, which had been renamed Petrograd in 1914). In March 1917, the devastating military setbacks, growing death toll, worsening economic situation and increasing levels of hunger in Russia led the Russian population to depose Czar Nicholas and form the Provisional Government, in what became known as the February Revolution. (Russia used the Julian calendar at the time, so it was February in Russia but March in other countries.)

In November 1917, communist (also called "Bolshevik") forces led by Vladimir Lenin moved to take over from the Provisional Government in what became known as the October Revolution, and Russia disintegrated into a civil war that lasted until 1921. Lenin's communism was partly based on the ideas of Karl Marx, an economic philosopher who contended that large social and economic changes were needed for workers to gain the benefits of their labor.

Nicholas II and most of his family, including his five children, were executed by gunfire on the night of July 16-17, 1918 by communist forces.

The new government made peace with Germany and withdrew from World War I.

Britain and the United States were alarmed at the growth of Lenin's forces and sent soldiers to Russia in an attempt to support anti-communist groups — known as the "White armies" in their fight against Lenin's "Red Army."

During the civil war, Lenin's forces expropriated and nationalized some of the businesses that it captured, which was part of a policy often referred to as "war communism," Silvana Malle, an emeritus professor of economics at the University of Verona in Italy, wrote in their book "The Economic Organization of War Communism, 1918-1921" (Cambridge University Press, 1985).

In 1921, the Red Army defeated the last major military forces opposed to Lenin, and the world's first communist country was born.

In the aftermath of World War I, a number of countries that had been controlled by the Russian Empire — such as Ukraine, Lithuania, Estonia and Latvia — gained their independence. For Ukraine, that independence was short-lived: Lenin's communist forces attacked Ukraine in 1919 and conquered most of the country by the end of 1921. Belarus also gained its independence for a brief time but was conquered by Lenin's forces in 1921.

Soviet Union's early years

Lenin didn't live to govern the Soviet Union for long; he died in 1924. In the short time he governed, a famine raged across the Soviet Union. A 1922 League of Nations (a forerunner to the modern United Nations) report stated that famine was "due to a combination of economic causes and an exceptionally severe drought." The report noted that estimates for the number of dead varied but was believed to be about 2 million people and put some of the blame on Lenin's "war communism" policies, saying that they had disrupted the Russian economy and farming practices. 

Following the civil war, Lenin backed away from the "war communism" policies that encouraged nationalization and expropriation, and he instead launched a "New Economic Policy" in 1921 that allowed for more private ownership and operation of enterprises, wrote Malle. 

Another important development during Lenin's rule was the imposition of restrictions on religious groups, as the communists worried that these groups may oppose communist rule. 

Lenin's health declined in his final years, and two senior officials — Joseph (or Josef) Stalin and Leon Trotsky — became rivals for leadership of the ruling Communist Party. After Lenin's death in 1924, Stalin became leader, and Trotsky was forced into exile — he was assassinated by Stalin's agents in Mexico in 1940. 

Stalin's rule

Stalin became known for his paranoia-induced purges and harsh treatment of some of the Soviet Union's minority groups. Stalin was also known for his elaborate attempts to paint himself in a positive light, even going so far as to have photos altered to show him making important decisions at historic moments — and to erase political opponents from other images. 

Stalin moved away from Lenin's "New Economic Policy" and instead instituted a policy of collectivization, in which people were forced to group their farm holdings together and operate as a collective. Stalin also began rapidly industrializing the Soviet Union, seeking to greatly increase the country's manufacturing capabilities. 

These policies further disrupted Soviet agriculture, which led to food shortages. Additionally, Stalin's fear of some minority groups — such as Ukrainians — led to policies that aimed to deprive them of food, Andrea Graziosi, a history professor at the University of Naples Federico II in Italy, wrote in a paper published in 2015 in the East/West: Journal of Ukrainian Studies. Estimates for the death toll vary but run into the millions. 

Stalin feared his own military and had many of the officers in his army killed between 1936 and 1938. Stalin also targeted religious officials, people he thought were loyal to Trotsky, and any others he believed may be disloyal to him. Sometimes these killings were preceded by torture and sham trials — an event that became known as "the Great Purge." The purge of so many trained military officers made it more difficult for the Soviet Union's military to fight the Germans when they invaded in 1941. 

World War II

Adolf Hitler had expressed his desire to attack the Soviet Union since before he came to power. In his book "Mein Kampf," which he wrote when he was in jail in 1924, Hitler said that Germany required "living space" and needed to conquer a vast amount of territory in Eastern Europe. 

Despite this, Stalin and Hitler signed a non-aggression pact on Aug. 23, 1939, in which the Soviet Union and Nazi Germany agreed to divide Poland between them. Germany then invaded the western half of Poland a week later, and the Soviet Union invaded the eastern half on Sept. 17. After Poland surrendered on Sept. 27, the Soviet military killed tens of thousands of captured Polish soldiers and officials in a series of massacres. 

With France and Britain busy fighting Germany, having declared war on Sept. 3, 1939, the Soviet Union launched an invasion of Finland in November 1939, in what became known as the Winter War. While the Soviet Union took significant losses, Finland ultimately had to sign a peace deal in May 1940 that ceded land to the Soviet Union. In June 1940, the Soviet Union invaded Lithuania, Latvia and Estonia, annexing all three countries into the Soviet Union. 

While Stalin expanded the Soviet Union, Hitler enjoyed rapid success in western Europe. France was overrun by Germany in a lightning military offensive — or blitzkrieg— that lasted from May 10 to June 25, 1940 and forced France to sign an armistice with Germany. While Hitler was unable to knock Britain out of the war in that offensive, or subdue Britain's air force during the Battle of Britain for long enough to launch an invasion of England, the fall of France meant that he was able to dedicate a vast amount of men and materiel toward a new objective — the invasion of the Soviet Union.

Prior to that invasion, Britain repeatedly warned Stalin that Germany was going to attack, but Stalin ignored it, presuming that the warnings were a ploy to draw the Soviet Union into war against Germany.

Stalin's own intelligence service was also warning him of a pending German invasion but Stalin didn't believe them either. "Stalin's blindness in the face of what his own people were telling him was intimately connected to the conviction that the warnings of a coming surprise attack were part of a British plot to embroil the USSR in a war with Germany," wrote Geoffrey Roberts, a history professor at University College Cork, in his book "The Soviet Union and the Origins of the Second World War: Russo-German Relations and the Road to War, 1933–1941" (Macmillan Education, 1995).

On June 22, 1941, Germany launched a massive invasion of the Soviet Union that advanced rapidly. On Sept. 8, the Germans started laying siege to Leningrad (now St. Petersburg) and came within miles of taking Moscow before being pushed back in a Soviet counterattack in December 1941.

Soviet forces, and Stalin himself, were taken by surprise with large numbers of Soviet troops being encircled and forced to surrender. In response to the German advance the Soviet Union moved factories into the interior of the Soviet Union and massively ramped up the production of war equipment.

In 1942, Germany launched a large offensive toward the city of Stalingrad (now called Volgograd). However, an entire German army became trapped in and around the city and was forced to surrender in January 1943. The German army also advanced into the Caucasus. Another German offensive at Kursk in July and August 1943 failed, and from that point on the Soviet Union was constantly on the offensive.

Soviet forces drove the German army out of the Soviet Union and then launched attacks in a push toward Germany. The war ended in May 1945 with the Soviet military in control of Berlin, along with a vast amount of territory in Central and Eastern Europe. Exact death counts vary, but sources generally agree that the Soviet Union suffered more than 20 million deaths during World War II — the highest of any country in any war in history.

Post war

In the aftermath of World War II, the Soviet Union created communist governments that were heavily influenced by Moscow in many of the territories that it occupied — such as Poland, Romania and Bulgaria. A communist government was established in Soviet-occupied areas of east Germany, creating The German Democratic Republic (GDR), often referred to as East Germany. The western areas of Germany occupied by Britain, the United States and France eventually formed the Federal Republic of Germany (FRG) often called West Germany — a democracy that followed an economic system based on capitalism. 

In Berlin, Britain, the U.S., France and the Soviet Union agreed to share control of the capital. As a result, the area of Berlin controlled by the Soviet Union became part of East Germany, while the areas controlled by the British, French and Americans would become part of West Germany — despite being in the east of the country and surrounded by East German territory. 

Many East Germans tried to leave for West Germany. The result was that the Soviets and the East German government heavily fortified the borders, and in Berlin they erected a wall that separated parts of Berlin controlled by East Germany from areas controlled by West Germany. The Berlin Wall would come to symbolize the divide and struggle between countries under communist control and those under a democracy. 

On March 5, 1946, former British prime minister Winston Churchill gave a speech at Westminster College in Missouri in which he said that "an iron curtain" of communist countries, heavily influenced by the Soviet Union, were being created. "From Stettin in the Baltic to Trieste in the Adriatic, an iron curtain has descended across the Continent," Churchill said in the speech. 

As the Soviet Union's strength increased, tensions between the Soviet Union and the United States increased too — giving rise to the Cold War. 

Cold War

During the Cold War, the U.S. and Soviet Union built up their militaries — particularly their nuclear arsenals — and supported different sides in conflicts across the world. Between June 24, 1948 and May 12, 1949, the Soviet Union prevented all shipments from traveling overland to the areas of Berlin controlled by the United States, Britain and France. The Soviet Union hoped to force the Allies to cede control over their parts of the city to the Soviet Union, wrote historian Roger Miller in his book "To Save a City: The Berlin Airlift, 1948-1949" (Texas A & M Press, 2000). In response, the Allies instigated a massive aerial resupply that resulted in Berlin getting enough food and goods to survive. The Soviet Union eventually accepted the blockade had failed and lifted the blockade.

This blockade helped drive forward the creation of the North Atlantic Treaty Organization (NATO) on April 4, 1949, in which the U.S., Canada and several countries in Western Europe signed a treaty saying that an attack against any of their countries would be considered an attack against all. The aim was to discourage the Soviet Union from launching any attacks against the member countries. On May 14, 1955, the Soviet Union created a similar alliance called the Warsaw Pact, between the Soviet Union and several communist states in Eastern Europe that it had heavy influence over.

Stalin died in 1953, and his successor Nikita Khrushchev eased some of the persecutions and killings that Stalin had been known for, although tensions with democratic countries continued to escalate.

During the Cold War, communist governments expanded beyond the Soviet Union and Eastern Europe. In December 1949, the Chinese Communist Party, led by Mao Zedong, took over mainland China, forcing their opponents to flee to Taiwan. The Soviet Union provided extensive support to communist China, but in time relations between the two countries weakened, with a border clash occurring in 1969.

In 1959, communist rebels led by Fidel Castro took over Cuba and enjoyed extensive Soviet support. Castro even allowed the Soviet Union to place nuclear missiles on the island — a decision that resulted in the Cuban Missile Crisis in 1962, during which Cuba was blockaded by the United States; the Soviet Union eventually agreed to remove the missiles. 

Communist governments in Asia were also drawn into the conflict between the Soviet Union and the U.S. Notably, communist regimes in North Korea and North Vietnam found themselves at war with the United States and its allies. The Korean War lasted from June 1950 to July 1953 and ended with an armistice. The Vietnam War raged from November 1955 to April 1975 and ended with Vietnam being unified under communist rule as U.S. forces pulled out of the country. Communist regimes also sprang up in Laos and Cambodia. 

During the Cold War, both the Soviet Union and United States built up their nuclear missile inventories — both sides eventually controlling thousands of nuclear missiles. More powerful nuclear weapons — such as the hydrogen bomb — were also invented.

This build-up of nuclear arms led to fears of human civilization being destroyed in a nuclear war. In an effort to lessen the chances of this happening, a hotline was established between Moscow and Washington, D.C. so that the two sides could quickly communicate. Additionally, a series of treaties were signed between 1960 and 1990 that aimed to limit the testing and size of nuclear arsenals.

The Cold War was not just a battle of military strength or ideology but also of scientific achievements, most notably in space. On Oct. 4, 1957, the Soviet Union succeeded in launching the satellite Sputnik, the first human-made satellite to orbit Earth; and on April 12, 1961, Yuri Gagarin became the first human being to orbit Earth.

End of the Soviet Union

A number of factors contributed to the collapse of the Soviet Union. In 1979, the Soviet Union invaded Afghanistan in an effort to support a communist government there. A number of insurgent groups backed by the United States fought back, leading to a costly decade-long war that forced the Soviet Union withdraw from Afghanistan in 1989. 

The cost of keeping a vast military in a region stretching from East Germany to the Pacific coast took a heavy toll on the Soviet economy, which was significantly weaker than the economies of the United States and its allies. 

The "Soviet Union had always suffered from its economic and financial inferiority relative to the US," wrote Vladislav Zubok, a professor of economic history at the London School of Economics, in his book "Collapse: The Fall of the Soviet Union" (Yale University Press, 2021). Zubok noted that the Soviet Union required a strong military backed up by a powerful ideological message in order to function and survive. The Soviet Union's economic problems, coupled with political problems that discredited its communist ideology, weakened it, Zubok noted. 

Additionally, groups opposing communist regimes — such as the trade union "Solidarity" in Poland — put more pressure on communist countries where the Soviet Union had strong influence to introduce reforms. Also, the Chernobyl nuclear disaster in April 1986 released radiation across a sizable area, creating an uninhabitable zone in what is today Ukraine. The disaster was expensive to clean up and cost the country's communist rulers credibility with their own population.

In 1985, Soviet leader Mikhail Gorbachev brought in reforms, sometimes called "perestroika" and "glasnot," that attempted to reform the Soviet economy by making it more open to outside investment and trade and allowing people some freedom to express opinions. Ultimately, these efforts were unsuccessful, and in 1989 the Berlin Wall came crashing down, and East and West Germany were reunified. The communist governments supported by the Soviet Union in Eastern Europe also collapsed in the late 1980s. Communist rule in the Soviet Union collapsed soon after, with many parts of the Soviet Union — such as Ukraine — re-asserting their independence.

Soviet legacy

Though the Soviet Union collapsed more than 30 years ago, its legacy lives on in many ways. Some of the communist governments the country supported — such as China, Cuba and North Korea — still exist. China is now the world's second-largest economy and a rising military power.

Additionally, Russian president Vladimir Putin regards the collapse of the Soviet Union as a tragedy and has attempted to bring parts of the former Soviet Union under Russian control or influence — the invasion of Ukraine being the latest example. 

Fuel from the Chernobyl nuclear plant poses an ongoing danger. Artifacts from the time also continue to turn up, including a Soviet spy radio that was found near the German city of Cologne. Buried fossil plants found during a Cold War military operation in Greenland look like they were buried yesterday, researchers recently reported.

Bibliography

Graziosi, Andrea "The Impact of Holodomor Studies on the Understanding of the USSR" East/West: Journal of Ukrainian Studies, vol 2, no 1, 2015

https://ewjus.com/index.php/ewjus/article/view/Graziosi 

Jonathan Smele and Anthony Heywood (eds) "The Russian Revolution of 1905: Centenary Perspectives" Routledge, 2005

Peter H. Lindert and Steven Nafziger "Russian Inequality on the Eve of Revolution," The Journal of Economic History, vol 74, no 3, September 2014, pp. 767 — 798 

https://www.cambridge.org/core/journals/journal-of-economic-history/article/russian-inequality-on-the-eve-of-revolution/A5CED37A899914A15F9CFB1777A441DF

Malle, Silvana "The Economic Organization of War Communism, 1918-1921" Cambridge University Press, 1985

Miller, Roger, "To Save a City: The Berlin Airlift, 1948-1949" Texas A & M Press, 2000

"Report on economic conditions in Russia: with special reference to the famine of 1921-1922 and the state of agriculture," League of Nations, Geneva, 1922

Retrieved from: https://cdm21047.contentdm.oclc.org/digital/collection/russian/id/4092 

Roberts, Geoffrey "The Soviet Union and the Origins of the Second World War: Russo-German Relations and the Road to War, 1933–1941" Macmillan Education, 1995

Zubok, Vladislav "Collapse: The Fall of the Soviet Union" Yale University Press, 2021

Private Earth-observation satellites are helping the world keep tabs on the Russian invasion of Ukraine.

Sharp-eyed spacecraft operated by Maxar Technologies and Planet have documented Russian troop movements and the damage done to strategic targets in Ukraine such as airbases. But the destruction and attacks have not been restricted to facilities with military significance, as photos from Virginia-based company BlackSky show.

Sunday (Feb. 27), BlackSky posted on Twitter satellite imagery collected over Kharkiv, the second-largest city in Ukraine. The shot shows new craters from Russian shelling, which "skirt the edge of residential areas, causing damage to nearby service and retail shops," BlackSky representatives wrote in the Twitter post.

Related: Satellite photos reveal details of Russian invasion into Ukraine

And Monday (Feb. 28), the company posted on Twitter a satellite shot of an Epicentr K — a big home-improvement store similar to Home Depot or Lowe's — ablaze in the Ukrainian city of Chernihiv.

The photo was taken Monday at 5:22 a.m. EST (1022 GMT; 12:22 local time in Chernihiv). It shows the Epicentr K ablaze, shrouded in plumes of smoke, after Russian shelling rocked the area, BlackSky representatives told Space.com via email. Scorched fields are also visible in the shot a few hundred meters east of the store, they noted.

The Russian invasion of Ukraine is first and foremost a humanitarian and geopolitical crisis, of course. But there could also be significant impacts to spaceflight and exploration down the road. Russia has already said it will halt launches of Russian-built Soyuz rockets from Europe's Spaceport in Kourou, French Guiana, for example.

Additionally, Dmitry Rogozin, the head of Russia's federal space agency, recently said that economic sanctions imposed on the nation as a result of the invasion could destroy the International Space Station partnership.

Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or on Facebook. 

Russian troops have captured the Chernobyl nuclear power plant, which still contains nuclear waste that could pose a threat to the surrounding area. What would happen if the site were to be bombed?

"Our defenders are giving their lives so that the tragedy of 1986 will not be repeated," Ukrainian President Volodymyr Zelenskyy tweeted a few hours before the power plant was seized yesterday. "This is a declaration of war against the whole of Europe."

Chernobyl is the site of four nuclear reactors, three of which have been decommissioned. The fourth was the source of the historic explosion in 1986. That reactor is now protected by an inner concrete sarcophagus and a new, 32,000-ton outer shell. In addition, spent nuclear fuel from the other reactors is still stored at the site, along with radioactive waste from contaminated equipment. 

Even though the reactor is covered, radiation has contaminated the entire site. In fact, dozens of radioactive elements were launched into the air during the meltdown, with a few of them considered the most dangerous to life, including the isotopes iodine 131, strontium 90, cesium 134 and cesium 137; the strontium and cesium isotopes have long enough half-lives that they still linger at the site, according to the International Atomic Energy Agency. 

Now, some public figures have expressed fears that any future shelling of these sites could spread this radioactive material far beyond Chernobyl's exclusion zone — an off-limits area around the disaster — even as far as neighboring countries.

On Thursday morning (Feb. 24), Anton Gerashchenko, an adviser and former deputy minister at the Ukrainian Ministry of Internal Affairs, wrote on Facebook, "If as a result of the occupiers' artillery strikes the nuclear waste storage facility is destroyed, the radioactive dust may cover the territories of Ukraine, Belarus and the EU [European Union] countries!"

Related: 5 interesting facts about Chernobyl

But the reality may not be so dire, according to Edwin Lyman, director of nuclear power safety at the Union of Concerned Scientists. "Even if there were an inadvertent shelling of that confinement structure, I think it would take more than that to mobilize a significant amount of radioactive material," Lyman told Live Science.

"It would be hard for me to imagine that kind of consequence," Lyman added. 

Spent fuel, or the radioactive elements that were used to fuel the power plant, continue to decay into more stable elements and, in doing so, continue to release heat, he said. 

"The most serious concern is the wet storage of spent fuel, because that's probably the most concentrated quantity of radioactive material on-site," Lyman said. "Generally, spent nuclear fuel still has decay heat. And so if it's in wet storage, there has to be some way of removing that heat." 

That fuel has been cooling for at least a couple of decades. "And so that decay heat is not that significant," Lyman said. "But still, if there was disruption to cooling … or if there was a breach of the pool that led to draining water, then that fuel could conceivably heat up to the point where it might burn. That's probably the biggest threat." 

However, such burning could take days or weeks, he added.

A more recent concern involves rising radiation levels around the facility, most likely a result of radioactive dust kicked up by military vehicles. But the type of dust and the radiation doses being measured suggest that this may not be much of a threat, either, according to Lyman.

"If it's a resuspension of dust, this is generally stuff that was not that mobile, or it would have blown away," he said. "So it's probably heavier particles of soil that don't disperse very far." More likely, he added, it might cause a temporary increase in radiation levels, and the data will show whether that's true.

But even such a temporary increase may not be a danger to human health, Lyman said.

"The dose rates they're finding are not that much greater than the usual dose rates in that area, which, admittedly, are probably about a hundred times the background dose of anywhere else in the world," Lyman said. "But even so, if [the troops] don't spend that much time in the area, it's not going to have a significant impact on their health compared to the threat of dying in war."

Nonetheless, Lyman thinks this event shows that plans for nuclear power need to consider the possibility of war. 

"The potential for nuclear power plants to be targets at wartime is something that really needs consideration," Lyman said, "especially when they're talking about expanding nuclear power to parts of the world that currently have more unstable regions." 

Originally published on Live Science.

As Russian military forces invade Ukraine and bomb the capital Kyiv and other cities, Ukraine's leading climate experts have withdrawn from an international scientific committee — just as the group is finalizing their approval of a landmark report on global climate change. 

Climate experts from nations around the world have spent two weeks evaluating the United Nations Intergovernmental Panel on Climate Change (IPCC) investigation, outlining how accelerating human-caused climate change is affecting societies and natural ecosystems worldwide. This is the second chapter in a sweeping climate assessment that is released every five to seven years, and it will propose strategies for adapting to current and future warming, sea level rise and ocean acidification, as well as extreme weather events, according to an IPCC statement. 

The IPCC's expert committee was entering the last days of review prior to releasing the report to the public on Monday (Feb. 28). But with Russian missiles falling on Kyiv and a Russian ground invasion underway, the delegation from Ukraine announced their withdrawal on Thursday (Feb. 24), citing safety concerns, Politico reported.

Related: Photos: The oldest known evidence of warfare unearthed

"We have some delegates from other cities, not only Kyiv, and they were forced to go to shelters," climate scientist Svitlana Krakovska, head of the Ukrainian delegation, told Politico. "But most important is that it's very difficult to think about climate change impacts when you have impacts of Russian missiles in our Kyiv, and tanks everywhere." 

One of the departing Ukrainian scientists told Chloé Farand, a senior reporter for Climate Home News, that "we need to think about [the] safety of our families and it is not possible to concentrate on the wording of the summary for policymakers under attack and bombing," Farand tweeted on Friday (Feb. 25).

According to the prior IPCC report released in August 2021, global climate change is "widespread, rapid and intensifying," with Earth experiencing climate disruptions that are unprecedented in thousands of years — and the role of humans in driving these changes is "unequivocal," Live Science previously reported.

The upcoming IPCC report is gleaned from more than 34,000 scientific publications and over 62,000 review comments; and it is authored by 270 scientists representing dozens of countries, IPCC representatives said in a statement. This is the first time that scientists from Ukraine are involved in an IPCC report as lead authors, Politico reported.

While the earlier report in 2021 outlined evidence of recent climate change and predictions for how that will continue to reshape our world in the coming decades, the upcoming report will focus on pinpointing critical ways in which human communities and natural ecosystems are vulnerable to climate change, and will outline options for mitigation and adaptation, according to the IPCC.

But for Ukraine's climate scientists, the most dire threats are currently much closer to home. 

"There's real danger for me and my family," Krakovska told Politico.

Originally published on Live Science.

The International Space Station program will continue business as usual, NASA assures us as the U.S. government levies new sanctions against Russia.  

Russia invaded Ukraine today (Feb. 24) in a series of military attacks. This action, which sparked international criticism, also prompted new and severe sanctions, U.S. President Joe Biden announced in a public address today. However, despite the new sanctions and continued warfare, NASA has asserted that civil cooperation between the U.S. and Russia in space, particularly with regard to the International Space Station, will continue.

"NASA continues working with all our international partners, including the State Space Corporation Roscosmos, for the ongoing safe operations of the International Space Station. The new export control measures will continue to allow U.S.-Russia civil space cooperation. No changes are planned to the agency’s support for ongoing in orbit and ground station operations," NASA said in a statement today that agency spokesperson Joshua Finch emailed to Space.com.

Related: The International Space Station will plunge into the sea in 2031, NASA announces

In a public, televised statement earlier today, President Biden discussed the new sanctions, stating that there will be "new limitations on what can be exported to Russia."  

"We estimate that we'll cut off more than half of Russia's high-tech imports. That will strike a blow to their ability to continue to modernize their military. It'll degrade their aerospace industry, including their space program," he added.

Biden's statements did not directly mention NASA, NASA's collaboration with Russia in space or the space station. However, Dmitry Rogozin, the director of Russia's space agency Roscosmos, posted a thread of tweets after the speech today that seemed to respond, under the assumption that these new sanctions will interfere with the two nations' space partnerships. 

"Do you want do destroy our cooperation on the ISS?" Rogozin tweeted in Russian (translated with Twitter translate). 

"If you block cooperation with us, who will save the ISS from uncontrolled deorbiting and falling into the United States or Europe? There is also the option of dropping a 500-ton structure to India and China. Do you want to threaten them with such a prospect? The ISS does not fly over Russia, so all the risks are yours. Are you ready for them?" Rogozin added.

However, despite Rogozin's online sentiments, NASA's statement that followed later tonight seems to suggest that at least for now, the new sanctions will not interfere with international collaboration off Earth.

Email Chelsea Gohd at cgohd@space.com or follow her on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.

Various satellites could be targets of the Russian military as it invades Ukraine, said the head of the U.S. National Reconnaissance Office (NRO), which operates the nation's fleet of spy satellites.

"I think we're seeing pretty clearly that Russia is committed to doing what they want to do in Ukraine, and they want to win," NRO Director Christopher Scolese said Wednesday (Feb. 23) at the National Security Space Association's Defense and Intelligence Space Conference, SpaceNews reported. 

"So I think it's fair to assume that, to the extent that they can, and to the extent that they feel it won't extend the conflict out of their control, that they will extend it into space," Scolese added. Russian military forces invaded Ukraine early Thursday local time, according to the New York Times.

Related: How many satellites orbit Earth?

Though he didn't make specific predictions about what measures Russia may take, Scolese noted that the nation already does GPS jamming, according to SpaceNews. He urged operators of both commercial and government satellites to be careful.

"I would tell everybody that the important thing is to go off and ensure that your systems are secure and that you're watching them very closely, because we know that the Russians are effective cyber actors," Scolese said, according to SpaceNews. "And, again, it's hard to say how far their reach is going to go in order to achieve their objectives. But it's better to be prepared than surprised." Read the whole story at SpaceNews here.

Russia has gathered about 150,000 troops on or near the Ukraine border, U.S. President Joe Biden said this week. He characterized the troop movements as an invasion and announced the imposition of a new set of economic sanctions in response. 

That response is likely to ratchet up, as Russia began military operations in Ukraine on Wednesday. Explosions were heard across the country, including in the capital city of Kyiv, according to CNN. 

Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or on Facebook. 

A letter written by Russian empress Catherine the Great on April 20, 1787, stressing the importance of the smallpox vaccine to the count of Malorossiya (modern-day Ukraine), will go up for auction on Dec. 1 at MacDougall's in London, according to news reports. 

That letter, previously held in an anonymous private collection, was recently displayed for the first time in Moscow and will go up for auction at MacDougall's auction house in London On Dec. 1, according to the Moscow Times. 

Catherine the Great, who ruled Russia from 1762 to 1796, was a major advocate for vaccination at a time when there was a lot of public resistance to the idea, according to MacDougall's. In 1768, she became the first person in Russia to be vaccinated against smallpox, and she had her son vaccinated soon after.

Related: 5 scariest disease outbreaks of the past century

The smallpox virus devastated the world for at least 3,000 years, before modern vaccination campaigns wiped it out in 1980, according to the World Health Organization (WHO). In 18th-century Europe, smallpox would sometimes kill off entire villages at once, according to MacDougall's.

The first successful smallpox vaccine wasn't available until 1796, when an English Doctor Edward Jenner realized that milkmaids who had caught cowpox did not catch smallpox, according to the WHO. Prior to that, during the time of Catherine the Great's reign, vaccination involved exposing people to the smallpox virus itself. 

Doctors would cut incisions in a healthy person's arm and insert threads of fabrics containing pus from a person infected with smallpox, according to MacDougall's. This primitive vaccination method made people sick for some time and had a 2% risk of death, or about 20 times lower than if a person was naturally infected with smallpox.

"Among the other duties of the Welfare Boards in the Provinces entrusted to you, one of the most important should be the introduction of inoculation against smallpox, which, as we know, causes great harm, especially among the ordinary people," Catherine the Great wrote in Cyrllic, a Slavic alphabet, in the newly unveiled letter addressed to Count Piotr Aleksandrovich, the governor-general and vice-regent of Malorossiya. "Such inoculation should be common everywhere."

In the letter, she wrote that the count should order each town to build temporary lodgings in abolished convents or small monasteries for people who couldn't be vaccinated at home.

The letter is "unique, especially given this situation we are all in," Oleg Khromov, a historian, told reporters via video at a press conference on Thursday (Nov. 18), according to The Moscow Times. 

Nowadays, vaccines are much safer than they were 200 years ago, but amid the unprecedented COVID-19 pandemic, many countries such as the U.S. and Russia are still battling widespread vaccine hesitancy.

When Louis XV, the ruler of France, died of smallpox in 1774, Catherine the Great reportedly said it was "barbarism" to die of the disease when they were living in the enlightened 18th century, according to the Moscow Times. 

"I very much hope that one day, maybe in the near future, we can say: 'What barbarism to die of COVID in the 21st century'," Yekaterina MacDougall, the auction house's co-director and Russian art expert, said at the press conference. 

The letter will be auctioned along with a portrait of Catherine the Great, which together are estimated to be worth up to $1.6 million, according to The Moscow Times.

Originally published on Live Science.

Chernobyl, the site of the deadliest nuclear accident of all time, should become a World Heritage site, Ukranian officials say. If their efforts succeed, the site of one of humanity's darkest chapters could join the ranks of the most iconic monuments to human culture and civilizations, such as Jordan's ancient city of Petra, the immense pillars of Stonehenge, Beijing's Forbidden City and the towering Easter Island statues in Rapa Nui. 

On April 26, 1986, 35 years ago today, a reactor explosion rocked the Chernobyl Nuclear Power Plant, located about 81 miles (130 kilometers) north of Kiev. Two workers died almost immediately, dozens died soon after and thousands more later died or were sickened by radiation exposure, as fallout from the disaster dispersed across Ukraine, Russia and Belarus. 

Soviet officials evacuated a 19-mile (30-km) area around the plant, now known as the Chernobyl exclusion zone. The Ukraine government seeks to add the plant — and the zone around it — to the global list of World Heritage Sites maintained by the United Nations Educational, Scientific and Cultural Organization (UNESCO), Reuters recently reported.

Related: 5 weird things you didn't know about Chernobyl

To be considered for the World Heritage List, a site "must be of outstanding universal value," and should display at least one quality that matches the agency's selection criteria, according to the UNESCO website. Some locations on the list represent breathtaking and unique examples of grandeur in the natural world, such as Yosemite and Yellowstone National Parks in the United States; Vietnam's Hạ Long Bay; Australia's Great Barrier Reef; and the primeval Białowieża Forest straddling Russia and Belarus.

Other locations, such as the Great Wall of China, Mexico's Chichén Itzá ruins and the city of Venice, Italy, earned a spot on the list for their importance in human history as well as their rare beauty. Sites on the list obtain certain legal protections and can receive financial assistance from the World Heritage Fund to help with preservation, according to UNESCO.

In order for a site to be eligible for UNESCO's list, it must first be added to a cultural and historic heritage list in its country of origin, Reuters reported. Oleksandr Tkachenko, Ukraine's Minister of Culture and Information Policy, told Reuters that the ministry initially sought to add the abandoned Chernobyl Nuclear Power Plant and nearby buildings to a list in Ukraine, and officials are now considering expanding that proposal to encompass the entire exclusion zone.

"We believe that putting Chernobyl on the UNESCO heritage list is a first and important step towards having this great place as a unique destination of interest for the whole of mankind," Tkachenko told Reuters.

"The importance of the Chernobyl zone lays far beyond Ukraine's borders," Tkachenko said. "It is not only about commemoration, but also history and people's rights."

In fact, tourism is already booming in the exclusion zone. One of the cities in the zone — Pripyat, home to about 49,000 people in 1986 — is today a post-apocalyptic ghost town, its homes, schools and hospitals uninhabited and reclaimed by plants and wildlife. The exclusion zone was initially opened to visitors in 2010, and Pripyat's eerie, overgrown buildings quickly became a popular destination for photographers and so-called disaster tourists. 

But Chernobyl tourism really took off after the success of HBO's 2019 dramatic series, "Chernobyl," with guides in the Ukraine reporting a 30% rise in 2019 bookings compared to the year before, Live Science previously reported. Approximately 124,000 tourists visited Chernobyl last year, and about 100,000 of them came from outside Ukraine, Agence France-Presse (AFP) reported in 2020.

Scientists are also keeping an eye on Chernobyl, to track how wildlife in the exclusion zone is adapting to levels of radiation exposure that make the zone unsafe for human habitation — and some of their findings are surprisingly positive. 

For example, recent surveys show that gray wolves (Canis lupus) are thriving near Chernobyl, likely in part because they have lots of prey and plenty of territory that's untouched by humans. And a rare species of Asian wild equine known as Przewalski's horse (Equus ferus przewalskii) is also flourishing in the exclusion zone, AFP reported. 

Originally published on Live Science.

Chernobyl, site of the world's deadliest nuclear accident, is now a surprisingly popular tourist destination. But lethal radiation still permeates the landscape around the site, so why is it safe to visit at all?

Ukrainian officials opened the area to tourists nearly a decade ago, declaring that visits were safe, though tours would be strictly regulated. Since then, thousands of people have flocked to the Chernobyl exclusion zone. [5 Everyday Things That Are Radioactive]

It's true that radiation in large doses can cause tissue damage and acute sickness and increase the risk of cancer, according to the American Cancer Society.

However, people everywhere on Earth are bathed every day in radiation that's a natural part of the environment. This includes terrestrial radiation emanating from Earth itself, internal radiation generated by living organisms, and cosmic radiation from the sun and stars, according to the U.S. Nuclear Regulatory Commission (NRC).

Calculating exposure

On average, a person in the U.S. is exposed to about 3 millisieverts (mSv) of radiation per year, which is considered to be well within safe exposure levels. Radiation from medical imaging technology ranges from less than 1 mSv to about 20 mSv for certain computed tomography (CT) scans, the American College of Radiology reported.

Radiation doses of 50 to 200 mSv can lead to chromosomal damage, while doses of 200 to 1,000 mSv can cause a temporary drop in white blood cell count; serious radiation sickness sets in at about 2,000 mSv, and death follows within days of exposure to 10,000 mSv, according to the Atomic Archive.

Soon after the nuclear meltdown at Chernobyl, dozens of cleanup workers at the plant were exposed to radiation levels as high as 8,000 to 16,000 mSv, the equivalent of 80,000 to 160,000 chest X-rays. This led to at least 134 workers developing serious radiation sickness and caused 28 deaths.

When the Chernobyl reactor exploded, it released deadly levels of radiation, but radioactive fallout wasn't distributed evenly across the surrounding area, due to weather conditions and changing winds. Locations that were farther away from the reactor became radioactive hotspots, "and there were villages that were reasonably close to the plant that didn't get much contamination," said Fred Mettler, a professor emeritus and clinical professor with the Department of Radiology at the University of New Mexico School of Medicine.

Even within villages, radiation was unequally distributed and could vary from street to street, as Mettler learned when he visited the region from 1989 to 1990 with the U.N. Scientific Committee on the Effects of Atomic Radiation (UNSCEAR).

Gauging the risk

The ruins of the Chernobyl reactor, now contained under a metal shell, are still highly radioactive and will likely remain so for up to 20,000 years. However, the zones in Chernobyl that are now open to the public may have initially received lower doses of radiation, despite their proximity to the damaged reactor, Mettler told Live Science.

Background levels of radiation around Chernobyl overall were also lower than the global average before the accident, which may have helped to mitigate the radiation boost from the accident, Mettler added.

Nevertheless, ongoing radiation-safety concerns dictate that tourists are restricted to certain areas and are not permitted to wander on their own, tour leaders with Chernobyl Tour wrote on the Ukrainian company's website.

An average one-day visit to Chernobyl begins and ends with passage through an official checkpoint for dosimetry control, or radiation measurement, and there is an additional radiation checkpoint midway through the tour, according to the State Agency of Ukraine on Exclusion Zone Management.

Visitors may not touch any structures or plants or remove anything from the zone, and they are prohibited from sitting or placing any camera equipment on the ground, Chernobyl Tour representatives said.

An estimated 60,000 tourists visited Chernobyl in 2018, Anton Taranenko, the chief of the Tourism and Promotion Department of the Kiev City State Administration, recently said at a news briefing; of all the most popular tourist destinations in Ukraine, "Chernobyl zone is the leader," said Taranenko, according to the National News Agency of Ukraine.

Ukrainian tourism agency representatives claimed that bookings to Chernobyl rose by about 30% in May and will likely be even higher during the summer months due to the popularity of the recent HBO series "Chernobyl," Live Science previously reported.

• 5 Weird Things You Didn't Know About Chernobyl
• Images: Chernobyl, Frozen in Time
• Chernobyl Nuclear Disaster 25 Years Later (Infographic)

Originally published on Live Science.

The new HBO series "Chernobyl" dramatizes the accident and horrific aftermath of a nuclear meltdown that rocked the Ukraine in 1986. Twenty-five years later, another nuclear catastrophe would unfold in Japan, after the magnitude 9.0 Tohoku earthquake and subsequent tsunami triggered a disastrous system failure at Fukushima Daiichi Nuclear Power Plant.

Both of these accidents released radiation; their impacts were far-reaching and long-lasting.

But how do the circumstances of Chernobyl and Fukushima compare to each other, and which event caused more damage? [5 Weird Things You Didn't Know About Chernobyl]

Only one reactor exploded at Chernobyl, while three reactors experienced meltdowns at Fukushima. Yet the accident at Chernobyl was far more dangerous, as damage to the reactor core unspooled very rapidly and violently, said Edwin Lyman, a senior scientist and acting director for the Union of Concerned Scientists Nuclear Safety Project.

"As a result, more fission products were released from the single Chernobyl core," Lyman told Live Science. "At Fukushima the cores overheated and melted but did not experience violent dispersal, so a much smaller amount of plutonium was released."

In both accidents, radioactive iodine-131 posed the most immediate threat, but with a half-life of eight days, meaning half of the radioactive material decayed within that time, its effects soon dissipated. In both meltdowns, the long-term hazards arose primarily from strontium-90 and cesium-137, radioactive isotopes with half-lives of 30 years.

And Chernobyl released far more cesium-137 than Fukushima did, according to Lyman.

"About 25 petabecquerels (PBq) of cesium-137 was released to the environment from the three damaged Fukushima reactors, compared to an estimate of 85 PBq for Chernobyl," he said (PBq is a unit for measuring radioactivity that shows the decay of nuclei per second).

What's more, Chernobyl's raging inferno created a towering plume of radioactivity that dispersed more widely than the radioactivity released by Fukushima, Lyman added.

Sickness, cancer and death

At Chernobyl, two plant workers were killed by the initial explosion and 29 more workers died from radiation poisoning over the next three months, Time reported in 2018. Many of those who died had knowingly exposed themselves to deadly radiation as they worked to secure the plant and prevent further leaks. Government officials relocated an estimated 200,000 people from the region, according to the International Atomic Energy Agency.

In the years that followed, cancers in children skyrocketed in the Ukraine, up by more than 90%, according to Time. A report issued by United Nations agencies in 2005 approximated that 4,000 people could eventually die of radiation exposure from Chernobyl. Greenpeace International estimated, in 2006, that the number of fatalities in the Ukraine, Russia and Belarus could be as high as 93,000 people, with 270,000 people in those countries developing cancers who otherwise would not have done so.

At Fukushima, there were no deaths or cases of radiation sickness directly associated with the accident — neither workers nor members of the public, according to the World Health Organization (WHO).

However, Japan's aggressive disaster response, which relocated 100,000 people from their homes near Fukushima, is thought to have indirectly caused around 1,000 deaths, most of which were people age 66 years or more, the World Nuclear Association reported.

No-go zones

Japanese authorities created a no-go zone around Fukushima that extended for 12 miles (20 kilometers); the damaged reactors were permanently closed, while cleanup efforts continued.

The extent of Fukushima's environmental impact is still unknown, though there is already some evidence that genetic mutations are on the rise in butterflies from the Fukushima area, producing deformations in their wings, legs and eyes. [See Photos of Fukushima's Deformed Butterflies]

Radiation from contaminated water that escaped Fukushima reached North America's western coast in 2014, but experts said that contamination was too low to pose a threat to human health. And in 2018, researchers reported that wines produced in California after the Fukushima accident had elevated levels of radioactive cesium-137, but the California Department of Public Health declared that the wines were not dangerous to consume.

Chernobyl's exclusion zone encompassed an area 18 miles (30 km) around the ruins of the plant, and the towns within its boundaries remain abandoned to this day. Trees in nearby forests turned red and died soon after the explosion. But decades later, diverse wildlife communities appear to be thriving in the zone, in the absence of human inhabitants.

By 2010, the Ukrainian government determined that danger from radiation exposure in the area around Chernobyl was "negligible," and the exclusion zone would be widely opened to tourists by the following year (though living in the area is still prohibited). But people who visit certain locations more than once will be supplied with handheld dosimeters to check their radiation exposure, so the visits are not without risk, Live Science previously reported.

What's more, radiation levels around Chernobyl can vary widely. Aerial drone surveys revealed in May that radiation in Ukraine's Red Forest was concentrated in previously unknown "hotspots," which scientists outlined in the region's most accurate radiation maps to date.

The Fukushima nuclear power plant is closed; nonetheless, ongoing concerns about safety during decommisioning and cleanup work still linger. The Tokyo Electric Power Company (TEPCO) recently announced that it would not hire foreign workers coming to Japan under newly relaxed immigration rules; TEPCO representatives cited concerns about the ability of non-native Japanese speakers to follow the plant's highly detailed safety instructions, The Japan Times reported yesterday (May 23).

In the end, both disasters provided important lessons for the world on the inherent risks of using nuclear energy, Lyman told Live Science.

"No one should underestimate the challenges needed to ensure nuclear power is safe enough for it to play a major role in the world's energy future," he said. "The key for regulators and operators is to always prepare for the unexpected."

• See Images of Chernobyl, Frozen in Time
• Fukushima Radiation Leak: 5 Things You Should Know
• Fire and Fury: How to Survive a Nuclear Attack

Editor's note: This story was updated on May 28 to indicate that the Fukushima power plant is no longer operating.

Originally published on Live Science.

Near ground zero of the catastrophic 1986 explosion at the Chernobyl Nuclear Power Plant, aerial drones recently revealed radioactive hotspots that aren't on official maps.

An interdisciplinary team flew special drones over Ukraine's Red Forest, one of the most radioactive spots in the world, which is located 0.3 miles (500 meters) from the Chernobyl complex, University of Bristol (UB) representatives announced in a statement.

Using data from the drone observations, the UB scientists, who are part of the National Centre for Nuclear Robotics (NCNR), created the most detailed map to date of radiation in the forest. They also pinpointed previously unsuspected locations where contamination was unusually intense, according to the statement. [See Images of Chernobyl, Frozen in Time]

The researchers deployed fixed-wing drones, flying 50 missions over the forest over 10 days and mapping a grid over an area measuring about 6 square miles (15 square kilometers). First, drones used a remote-sensing method called lidar — light detection and ranging — to create 3D maps of the terrain. Then, lightweight gamma spectrometers scanned for signatures of radioactive decay.

Radiation contamination in the Red Forest was already known to be higher overall than in any other natural site on Earth. Nevertheless, the scientists found that radioactivity there was unevenly distributed. While radiation had subsided in some areas, others maintained contamination levels that were dangerously high, project leader Tom Scott, a professor at the UB School of Physics, told British television network ITV.

They detected one unexpected hotspot in the ruins of a facility that performed soil separation during cleanup efforts after the accident, the BBC reported. Spent nuclear fuel in the abandoned building was emitting so much radiation that exposure for just a few hours would dose a person with as much radiation as is normally absorbed over an entire year, Scott told the BBC.

And certain radioisotopes that were identified in the Red Forest have very long half lives (the time required for half of their atomic nuclei to decay), "so they're going to be around for a long time," Scott told ITV.

For decades after the accident, the Chernobyl exclusion zone — an area about 1,660 square miles (4,300 square km) around the nuclear complex — was so toxic that nearly all of it was strictly off-limits to people (though wildlife continued to thrive there). But as the radioactivity dissipated, parts of the zone have been opened to tourists, ITV reported.

The recent expedition to the Red Forest was the first in a series of surveys that NCNR will conduct in Ukraine over the next year, and the new maps it is making will help officials to prevent risks to visitors, according to the statement.

• Chernobyl Nuclear Disaster 25 Years Later (Infographic)
• The Top 10 Ways to Destroy Planet Earth
• Fire and Fury: How to Survive a Nuclear Attack

Originally published on Live Science.

What might be passed over as two oddly shaped rocks are the work of Stone Age artisans who sculpted the rocks into beady-eyed snake heads, archaeologists have found.

It's a mystery why these ancient people, who lived in what is now Ukraine, created the stoney serpents, but the researchers have a good guess.

"These sculptures could have ritual purpose," said study lead researcher Nadiia Kotova, an archaeologist in the Department of the Eneolithic and Bronze Age at the Institute of Archaeology National Academy of Sciences (NAS) of Ukraine. "They were probably used during ceremonies." [In Photos: Intricately Carved Stone Balls Puzzle Archaeologists]

Kotova and her team found the snakey stones in 2016, during an excavation at Kamyana Mohyla I, an archaeological site near the city of Terpinnya. Both stones, although different ages, were found near ancient bones and flints from the same period: the Mesolithic, which is the middle Stone Age between the earlier Paleolithic and later Neolithic. There were many sandstones at the site, but "these two had quite a strange shape, so we decided to look closer," Kotova told Live Science in an email.

The "older" figurine was found near an open fireplace, near piles of shells and flint tools. Using organic matter from the fireplace, the researchers were able to radiocarbon date the yellow sandstone snakehead to between 8300 B.C. and 7500 B.C.

This snakehead is small, measuring only 5 inches by 3 inches (13 by 6.8 centimeters) and weighing almost 3 lbs. (1,215 grams). It has a triangular shape with a flat bottom. "Two rhombic eyes were carved on the upper surface alongside two knobs" on the stone, the researchers wrote in the study. "A wide, long line represents a mouth."

Regrettably, the snake was "damaged on the 'nose' during excavation," the researchers wrote in the study.

The "younger" stone snake was also found by a fireplace and was dated to about 7400 B.C. It measures about 3 inches by 2 inches (8.5 by 5.8 cm) and weighs just under 1 lb. (428 grams), meaning it can comfortably fit in a person's hand, Kotova said.

"The smaller stone has a flattened, round shape and so-called 'neck,'" Kotova said. "There are two deep traces, probably the eyes of the creature. There is also kind of a nose."

The two findings represent the only snakehead stones known at Kamyana Mohyla I. However, scientists did discover a fish-like stone sculpture at the nearby Kamyana Mohyla, a giant stone pile just a stone's throw from the snakeheads' spot.

Archaeologists don't know much about the people who made these sculptures, except that these prehistoric inhabitants lived on the steppe of the northwestern region of the Sea of Azov. "They made tools from stones, flints and bones and hunted with bows and flint arrows," Kotova said. "It was the society of hunters and gatherers. Unfortunately, we don't know much about their cultural traditions yet."

The study was published online today (Dec. 12) in the journal Antiquity.

• In Images: An Ancient European Hunter-Gatherer
• Photos: Stone Age Skulls Found on Wooden Stakes
• Photos: Bronze-Age Stone Tools Unearthed at Site of Ancient Stream

Originally published on Live Science.

This article was originally published at The Conversation. The publication contributed the article to Live Science's Expert Voices: Op-Ed & Insights.

The German energy giant RWE has begun to “reverse flow” supplies of gas from Europe back to Ukraine via Poland, a process first arranged in 2012, with an agreement to deliver up to 10 billion cubic metres (bcm) of gas per year.

The question for the Ukrainian interim government and state-owned energy firm Naftogaz is how this gas will be delivered, how soon, and whether it will be enough. Hungary has the capacity to deliver 5.5 bcm, Poland could deliver 1.5 bcm, and Romania could potentially provide 1.8 bcm capacity, but not before 2016-17 at the earliest.

Talks between Ukraine and Slovakia have renewed in an effort to tap into its capacity to deliver 9 bcm of gas, but the Slovak government and pipeline operator, Eustream, are anxious to ensure that feeding gas back to Ukraine does not breach its contracts with Russian state-owned energy giant Gazprom. Given that Ukraine imports around half of its annual 55 bcm of gas consumption, even with these new suppliers it will remain dependent on Russian gas.

The current situation comes as Kiev faces price hikes from US$285 to US$485 per thousand cubic metres of Russian gas, after Gazprom cancelled discounts offered in April 2010 and December 2013. The new price is significantly higher than, for example, the price of US$399 paid for Russian gas at the German border.

Naftogaz has struggled to pay for its Russian gas imports since late 2013, and now owes Gazprom more than US$2 billion. The combination of Naftogaz’s debts and unwillingness to pay the higher price means that many in Europe fear a suspension of Russian gas supplies to Ukraine – which, as it travels through the same pipelines, would also interrupt Russia’s gas exports destined for Western Europe.

This is not the first time that Russia and Ukraine have clashed over gas prices. For more than a decade following the collapse of the Soviet Union, Ukraine benefited from Russian gas import prices far lower than those in Western Europe. Attempts by Gazprom to raise gas prices for Ukraine resulted in disputes and suspensions of gas supplies to Ukraine in January 2006 and January 2009.

With Gazprom delivering 140 bcm to the EU in 2013 – more than a quarter of the EU’s total gas consumption – this has left many countries scrambling to find alternative ways to meet their needs.

Find new routes

Russian gas is delivered to the EU via several routes, of which the Ukraine pipelines are the most important, accounting for 55-60%. Around 25-30% travels through Belarus, and the remainder comes through the new Nord Stream gas pipeline, which runs under the Baltic Sea directly from Russia to Germany.

Opened in late 2011, Nord Stream is 51% owned by Gazprom, with the remaining shares owned by European energy companies (BASF Wintershall, E.On, Gasunie, and Gaz de France). The pipeline’s capacity can reach 55 bcm per year, but due to regulatory problems in Germany is currently operating at half capacity.

Gazprom is also planning the South Stream pipeline, another joint-stock partnership between Gazprom and local energy companies in each of the states it travels through. This would link Russia to Bulgaria under the Black Sea, through Serbia, Hungary, and Slovenia to northeast Italy.

If built, the 63 bcm per year capacity of South Stream and the 55 bcm capacity of Nord Stream combined could reduce Russia’s dependence on the Ukraine pipelines to almost nothing, if Gazprom’s current export levels of gas to Europe remain stable.

Find new sources

Ukraine’s efforts to find alternative sources of gas imports have led to protests from Gazprom. The gas that would be exported from the European market to Ukraine would actually be Russian gas, being re-exported at a profit by European energy companies. Gazprom claims such a scheme could be illegal, but has not clarified on what grounds.

Re-exporting imported gas was previously forbidden in Gazprom’s contracts with European energy companies, under the “destination clause”. But by 2006, these clauses had been removed on the grounds that they infringed Article 81 of the European Community Treaty (restrictive business practices). So any European energy company – theoretically, at least – now has the right to re-export gas, regardless of its source or destination.

The legality of re-exporting Russian gas from Europe to Ukraine may hinge on Gazprom’s gas transit contracts with Naftogaz and Eustream. These contracts effectively “reserve” the pipeline for delivering gas from east to west. Should Naftogaz and Eustream reverse the flow of their pipelines without Gazprom’s agreement, they could be in breach of contract. This condition applies even if those pipelines are not being used at full capacity, as is currently the case, and even if Naftogaz and Eustream are still able to fulfil their commitments to deliver Russian gas from east to west.

Recognise mutual dependence

They key aspect of this situation is the extent to which all parties depend on each other. While the EU sources more than 25% of its gas consumption from Russia, around 60% of Russia’s gas exports are to the EU. Almost 60% of Russian gas exports to the EU are delivered via Ukraine, which is itself also almost entirely dependent on Russia for its gas imports (imports account for just over half of Ukraine’s gas consumption).

Occasionally the European media refer to Russia’s gas as an “energy weapon”, or to the possibility that Russia may “turn off the taps” as leverage in a political dispute with the EU. But this is simply not credible: both Russia and EU member states and their energy companies have a vested interest in maintaining good trading relations.

For Europe, the disintegrating Gazprom-Naftogaz relationship is the greater worry. Both sides have in the past failed to use arbitration and dispute resolution to resolve their disagreements, and the ongoing arguments and two complete gas suspensions were the result. Given the recent statements by Russian and Ukrainian officials, another suspension of Russian gas supplies to Ukraine cannot be ruled out.

Jack D. Sharples received funding from the Economic and Social Research Council.

This article was originally published on The Conversation. Read the original article. Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google +. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science.

Following its controversial annexation of Crimea, Russia has claimed that it is now withdrawing troops from its border with Ukraine, but NATO officials have expressed doubts that the military power will pull back anytime soon.

"Unfortunately, I cannot confirm that Russia is withdrawing its troops," NATO Secretary General Anders Fogh Rasmussen said today, as quoted by CNN. "And this massive military buildup can in no way contribute to a de-escalation of the situation."

The current geopolitical chess match in Crimea and Ukraine shines a bright light on NATO and its historical role as a counterweight to Russian aggression. [The 10 Epic Battles That Changed History]

What is NATO?

NATO, or the North Atlantic Treaty Organization, formed in 1949 as the clouds of World War II still hung over much of Europe.

After the Soviet Union blocked Allied access to parts of Berlin in 1948, and Germany was split into two separate nations, the United States and European nations (including France, the United Kingdom, Canada, Italy and Iceland) responded by signing the North Atlantic Treaty.

The treaty states that member nations will respond collectively to an attack against any individual NATO member. Participating countries are not obligated to respond with military force, but can choose to support other members with political, economic or other forms of aid.

NATO's mission

"NATO's essential purpose is to safeguard the freedom and security of its members through political and military means," the Brussels-based group's website states.

NATO has also expressed a commitment to "democratic values" and the sharing of resources that will enhance the defense and security of member nations by preventing conflict.

But the group's embrace of military action is unambiguous: "If diplomatic efforts fail, it has the military capacity needed to undertake crisis-management operations," the website states.

Who's in NATO?

Currently, NATO membership stands at 28 nations. The original members from 1949 are Belgium, Canada, Denmark, France, Iceland, Italy, Luxembourg, Netherlands, Norway, Portugal, the United Kingdom and the United States.

In the years since those founding members signed, seven additional nations have joined NATO: Greece, Turkey, Germany, Spain, the Czech Republic, Hungary and Poland.

In 2004, one year after NATO took command of the coalition of nations fighting in Afghanistan, another set of countries joined: Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia and Slovenia. In 2009, Albania and Croatia gained membership.

Besides its 28 member nations, NATO has strategic partnerships with other countries through its "Membership Action Plan," which offers assistance and advice to nations seeking membership in NATO. Four countries are currently trying to join NATO through those plans: Georgia, Bosnia/Herzegovina, Montenegro and the Macedonian Republic.

NATO and Ukraine

For years, Ukraine and NATO have been slow dancing toward membership, but it's been a complicated pas de deux. In 1997, a formal NATO-Ukraine Commission was created within NATO to facilitate efforts toward membership. In addition to staging joint military exercises, Ukraine joined NATO's anti-piracy missions in the Indian Ocean in 2013.

But Ukraine also has a long-standing relationship with Russia, and the two associations are somewhat incompatible: Russia has consistently opposed NATO expansion, which the country views as an economic, political and military threat.

In 2010, Viktor Yanukovych won the presidency of Ukraine. As part of his pro-Russian agenda, Yanukovych declared that Ukraine would no longer pursue NATO membership, instead strengthening bonds with Russia.

Russia and NATO

Yanukovych's ouster in a February 2014 coup triggered a hard-hitting Russian response, which included annexation of the Crimean peninsula, formerly part of Ukraine. Russia has also announced a sharp increase in the price Ukraine would pay for Russian natural gas ($385.50 per 1,000 cubic meters, up from $268.50, CNN reports).

These Russian maneuvers have alarmed many in NATO, which has announced a series of joint military exercises that would put NATO forces in close proximity to Russian troops.

"Another important aspect of relations is the support given by NATO and individual allies for Ukraine's ongoing reform efforts, particularly in the defense and security sectors," NATO said in a statement. "These reforms are vital for the country's democratic development."

Follow Marc Lallanilla on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

In the ongoing international showdown between Russia and Ukraine, the region known as Crimea has emerged as the top prize — a position it has held, for better or worse, for millennia.

Russian-allied troops in Crimea have taken hold of key targets — including airports, government offices and military bases — and Russian military leaders demanded the complete surrender of all Ukrainian forces in Crimea on Monday (March 3).

What is it about this peninsula that makes it so desirable as a geopolitical trophy? The answer lies in Crimea's unique climate, diverse culture, geography and often-troubled history. [The 10 Epic Battles That Changed History]

1. Crimea is semi-autonomous

Crimea has been a part of Ukraine since 1954, when Soviet leader Nikita Khrushchev "gave" it to Ukraine, which was then part of the Soviet Union until its dissolution in 1991. Since that time, Crimea has existed as a semi-autonomous region of the Ukrainian nation, with strong political bonds to Ukraine — and equally strong cultural ties to Russia.

Crimea has its own legislative body — the 100-member Supreme Council of Crimea — and executive power is held by a Council of Ministers, which is headed by a chairman who serves with the approval of the president of Ukraine. The courts, however, are part of the judicial system of Ukraine and have no autonomous authority.

2. Crimea's climate and geography

Crimea is surrounded almost completely by the Black Sea, and encompasses an area of about 10,000 square miles (26,000 square kilometers), roughly the size of the state of Maryland. The peninsula is connected to the Ukrainian mainland by the narrow Isthmus of Perekop.

And Crimea — which rests about 200 miles (322 km) northwest of Sochi, Russia — enjoys the same mild, year-round climate as the site of the 2014 Winter Olympics. The climate is a big reason why Russian leaders are so adamant about keeping Crimea within their sphere: The Black Sea is home to Russia's only warm-water ports.

Though Crimea is recognized worldwide as a part of Ukraine, the Russian Navy has kept its Black Sea Fleet stationed at a naval base in Sevastopol (in southern Crimea) since the late 1700s. In 2010, Russia negotiated an agreement that allows the country to share the all-important Sevastopol naval base through 2042, in exchange for deep discounts of about $40 billion on natural gas from Russia.

3. Guns, gas and grains

Beyond the strategic importance of Crimea and Ukraine, the situation in the region is complicated by both the abundance and scarcity of certain natural resources.

Ukraine has been called "the breadbasket of Russia" for centuries, since the region produced much of the grain needed to feed the country's vast czarist empire. Even today, Ukraine is one of the world's largest producers of corn and wheat, and much of that passes through Crimean ports. (More than 50 percent of the Crimean economy is devoted to food production and distribution industries, according to Ukrainian government figures.)

But the semiarid climate that makes Crimea such a popular tourist destination also makes the peninsula largely dependent on Ukraine for water, as well as about 70 percent of its food, according to Slate.

The energy picture in Crimea and Ukraine is also tricky: Crimea relies on Ukraine for much of its electricity, and Europe relies on Russia for about 25 percent of its natural gas, according to CNN. Furthermore, the natural gas that Russia sends to Europe travels largely through pipelines that snake across the Ukrainian landscape.

That's why any instability in the region is bound to send shock waves through international energy markets: Crude-oil prices jumped by $2.33 a barrel on Monday (March 3), due in large part to jitters over the Russian aggression in Crimea, according to the Associated Press.

4. The Crimean War

If you're looking for a time when the geopolitical scene in Crimea was stable, you won't have much luck. The peninsula has, throughout its long history, been occupied by ancient Greeks, Romans, Goths, Huns, Ottomans, Mongols, Venetians and Nazi Germans. [In Photos: Amazing Ruins of the Ancient World]

From 1853 to 1856, the Crimean War roiled the area, as France, England and the Ottoman Empire fought the Russians for control of Crimea and the Black Sea. Russia eventually lost and ceded its claim to the peninsula, but not before the cities and villages of Crimea were ravaged.

Despite its devastation, the Crimean War was noteworthy for several advances: Florence Nightingale and Russian surgeons introduced modern methods of nursing and battlefield care that are still in use today; the Russians soon abolished their medieval system of serfdom (in which peasants were bound to serve landowners, even as soldiers); and the use of photography and the telegraph gave the war a distinctly modern cast.

5. Crimean Tatars wield influence

For proof that the past is never really gone, you need look no further than Crimea, home to an ancient ethnic group known as the Tatars, who still wield considerable influence.

Primarily Muslim, the Tatars of Crimea were instrumental in making the peninsula one of the centers of Islamic culture. They were also known as slave traders who raided lands as far north as modern-day Poland.

The Tatars didn't fare well in the Crimean War or in later conflicts, and many fled the region. Soviet leader Joseph Stalin may have dealt the Tatars their cruelest blow: By shipping food out of Crimea to central Russia in the 1920s, Stalin starved hundreds of thousands of Tatars.

During World War II, Crimean Tatars were deported by the thousands to serve as laborers and other menial workers in Russia under inhuman conditions — about half the Tatar population reportedly died as a result. [Video - World War II Underwater Graveyard Discovered]

After the fall of the Soviet empire, Tatars began to return to their ancestral Crimean homeland, where they now number about 250,000 — roughly 12 percent of the Crimean population.

For obvious reasons, the Crimean Tatars take a dim view of renewed Russian incursions into their homeland, and are likely to put up some resistance. "If there is a conflict, as the minority, we will be the first to suffer," Usein Sarano, a Crimean Tatar, told Reuters. "We are scared for our families, for our children."

They may be outnumbered, however: While much of western Ukraine favors a greater political, economic and cultural alliance with Western Europe and the United States, the majority of those in eastern Ukraine and Crimea — where many residents are ethnic Russians — look to Moscow for leadership and support.

Follow Marc Lallanilla on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

The site of the worst nuclear accident in history will be a new tourist attraction, the Ukranian government announced Monday (Dec. 13). The area around Chernobyl is scheduled to open to visitors next year.

Where tourists are allowed to go, how long they may stay, and what they eat will be carefully controlled, government officials say, so the radiation risks are "negligible."

"They will be properly channeled at all times," said Vadim Chumak at the Research Center for Radiation Medicine of Ukraine.

Scientists researching the effects of Chernobyl at the U.S. National Cancer Institute declined comment, deferring to Chumak, but an unaffiliated biologist pointed out that many other adventurous vacations (think a steep mountain climb) are not risk-free, either.

The fallout

A nuclear reactor exploded at Chernobyl in Ukraine in 1986. The blast knocked the 2,000-ton lid off the reactor and spewed out 400 times more radioactive fallout than the Hiroshima bomb, contaminating more than 77,000 square miles (200,000 square kilometers) of Europe. Roughly 600,000 people were exposed to high doses of radiation. [Top 10 Greatest Explosions Ever]

The exclusion zone around Chernobyl — the highly contaminated area covering a radius of 19 miles (30 km) around the doomed reactor — will be open to visitors next year.

"The visits of tourists would be strictly controlled, so that the radiation risks would be negligible," Chumak, who heads the Ukraine research center’s laboratory of external exposure dosimetry, told LiveScience.

After the disaster, it was uncertain how contaminated the surroundings were, and in a hurry, the authorities declared an arbitrary distance from the reactor off-limits. Researchers later found that some areas within the exclusion zone contained only low levels of radiation. Also, radioactive material decays over time, and some of it disappeared soon after the explosion.

Still, other areas of the exclusion zone, such as the radioactive-waste disposal sites, the sarcophagus entombing the remains of the damaged reactor, and the Red Forest where much of the radioactive material from the reactor spewed, are still hazards. Radioactive cesium, strontium and plutonium are also still around. Plutonium in particular is expected to linger; it takes thousands of years to decay.

"However, the visits of the tourists would be strictly monitored so that they would not have access to locations with relatively high radiation levels," Chumak said. "The visitors would be safe from the radiation point of view, as they would not be free to go wherever they want.”

Don't eat the fruit

Ecologist and evolutionary biologist Anders Moller at the University of Paris-Sud in France said he has spent one to three weeks in the exclusion zone every year for the last two decades, to assess the effects of radiation on animals, plants and people there.

"The level of background radiation I experience during such visits amounts to something like that from an X-ray at a doctor's office," Moller said. "But there is extreme variation in how 'hot' different spots are. There is a more than a factor-of-10,000 difference between the cleanest and the hottest areas in the exclusion zone."

The biggest danger for all life in that area, Moller said, would come from consuming anything that contained radioactive material. "It might end up in your gut and cause serious problems," he explained.

"I don't eat the local produce. The people that live in this contaminated area don't have this luxury, and live from what they grow in their gardens. I've seen with my own eyes with a Geiger counter that locally grown potatoes and onions and so on are often contaminated."

Tourists will not be given any food from the area, "and no airborne radioactivity — dust or aerosols — will be present in the areas visited by tourists," Chumak said. (People who work at Chernobyl must wear respirators where there is a risk of radioactive particles in the air, and they change into and out of special clothing. They are sometimes also given more-protective suits and masks.)

A limited amount of tourism to Chernobyl is already being tolerated, and given the new Ukrainian administration's increased emphasis on economic development, opening Chernobyl for tourism could pay off. For instance, Chumak said, soccer fans attending the European Cup in 2012, to be held in Ukraine and Poland, might be interested in making side trips to Chernobyl.

So what is there for visitors to see? Stopovers would include Chernobyl town, "where the level of man-made radiation is small in comparison to the natural radiation background," Chumak said. (The world is normally bathed in a low level of radiation.)

There is also a special viewing terrace that looks upon the sarcophagus. "The closer you get to the sarcophagus, the higher the external radiation, thus justifying the use of a location far enough from the sarcophagus to limit the exposure to a level about two to three times the natural background," Chumak said.

Tourists also could go close to the power plant and "see and feed large catfishes from the nuclear power plant cooling pond."

One could also visit the town of Pripyat, "which had been evacuated the day following the accident," Chumak added. "The radiation levels there are relatively high, but due to limited stay time, cumulative doses are kept very low." If they made return trips, tourists would be given personal dosimeters to measure their radiation levels, Chumak said.

Moller called the exclusion zone "a ghostly place. It is peculiar in many ways. There are all these villages that have been permanently evacuated, and you can see and hear many fewer birds and other signs of nature."

"It's a kind of reverse ecotourism," said biologist Tim Mousseau at the University of South Carolina at Columbia. "It could prove useful for educating people about the potential consequences of accidents related to nuclear energy, and I think any kind of increased awareness there is good.

"As long as people are informed that it's not completely risk-free, I don't see any problem with it. When people try and climb Mount Everest, they know hundreds of people have died trying, and they still do it."

However, Moller added, "I'm not sure this is where I would go for my honeymoon."

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