Science news this week: NASA announces nuclear rocket, space reproduction proves difficult, and why weed gives people the munchies

This week's science news was crammed with fascinating revelations about the workings of the human body, leading with the finding that zero gravity means zero game for humans looking to reproduce in space.

A new study revealed that sperm navigation, fertilization and embryo development were severely hampered in simulated microgravity. The findings could pose a serious problem for future space colonization.

But that doesn't mean you should bet against human adaptability, as Live Science's interview with evolutionary anthropologist Herman Pontzer revealed. In fact, readily adjusting to new circumstances is one of our species' strong suits. Take human fingernails: They may have evolved tens of millions of years before touch screens, but that didn't stop one chemistry student from developing a clear polish to turn them into styluses.

Other weird and wonderful biological revelations abounded this week, with the discovery that viruses in the gut play a possible role in the prevention of blood sugar spikes. Researchers also found that the eyes of people with synesthesia physically react as if the colors they saw were real.

NASA announces nuclear rocket

NASA announces 'near‑impossible' space plans, including $20B moon base and humanity's first nuclear-powered interplanetary spacecraft

This week, NASA laid out some ambitious plans for its return to the moon. The space agency's administrator, Jared Isaacman, announced he was canceling a planned space station in lunar orbit to use its parts for a $20 billion permanent base on the moon's surface, while also sending a nuclear-powered spacecraft to Mars.

The new lunar-base plans, which will use a fleet of drones and robotic landers to establish a nuclear power station on the moon's surface by 2036, may be partially motivated by a desire to stay ahead of China in the new space race.

Whether the plans are realistic, or simple lunacy will likely come into clearer focus next week, as the space agency's Artemis II moon rocket makes its final bid to launch before its April 30 deadline.

Discover more space news

—Chinese lander reveals giant 'cavity' of radiation between Earth and the moon — and it could change how lunar exploration is done

—An anomaly in Mars' mantle could trigger volcanoes to erupt — and may be causing the whole planet to spin faster

—Cannonball-size meteorite crashes through roof of Texas home as multiple 'fireballs' rain down on the US

Life's Little Mysteries

Why does cannabis give people 'the munchies'?

A common side effect of smoking cannabis is being incredibly ravenous. So what explains this effect? Live Science's Kenna Hughes-Castleberry investigated why cannabis gives people "the munchies."

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The Iran war is a climate catastrophe

Iran war has already released a staggering amount of CO2 — and the destruction of schools, homes and buildings is the biggest source

As the war in Iran enters its fifth week with scant signs of a letup, we reported on an alarming finding: The first two weeks of the war had already released a staggering amount of carbon dioxide, and the biggest source of the emissions was in the destruction of buildings that will need to be cleared and rebuilt.

The war has drained the global carbon budget faster than 84 countries — the lowest carbon emitters — combined. The aftershocks of the war are expected to have an even bigger climate impact than the fighting itself, as countries seek to buffer against fuel and fertilizer shocks caused by Iran's blockade of the Strait of Hormuz.

Discover more planet Earth news

—Scientists are racing to save Australia's 'zombie tree' from a fast-spreading fungal disease

—Drought could fuel the rise of antibiotic-resistant superbugs as climate change worsens, new research suggests

—Antarctica could warm 1.4 times faster than the rest of the Southern Hemisphere in the coming decades, study finds

Also in science news this week

—Brain aging results from a loss of control over how genes are regulated, mouse study suggests

—Roman mosaic shows topless woman battling leopard in arena, study finds

—1,000-year-old altar and human sacrifices from Toltec Empire discovered in Mexico

—AI compressed billions of years of evolution into seconds to create 'Lego-like robots' that can recover even when they lose limbs

—A new twist on matter? Strange 'Half-Mӧbius' molecule has rare properties chemists have never seen before

Science long read

DNA shed by every living thing is lurking in the environment — and it could tell us how Earth is changing in real time

Genetical material is everywhere around us — in the soil, water and air — and it leaves behind invisible fingerprints for entire ecosystems. Tracing it could enable scientists to detect species, map food webs and chart biodiversity without tracking a single organism.

But analyzing the ingredients of this ambient DNA soup is an overwhelming task. In this long read, Live Science investigated the scientific breakthroughs that could soon bring about real-time monitoring of Earth's biosphere.

Something for the weekend

If you're looking for something a little longer to read over the weekend, here are some of the best analyses, crosswords and opinion pieces published this week.

—Is the metaverse finally dead and buried? What's really going on with the embattled idea of living in virtual worlds [Analysis]

—Live Science crossword puzzle #36: America's national bird — 11 across [Crossword]

—Our fossil fuel economy is a house of cards and Trump's war in Iran is about to topple it. The need for a clean energy transition has never been clearer. [Opinion]

Science news in pictures

Extreme blast of Arctic air from polar vortex paints a picturesque plume off Florida coast — Earth from space

This photo, snapped by NASA's Terra satellite in February, shows a bright plume of swirling marine mud that was whipped up off the coast of Florida following an Arctic blast that brought severe winter weather to large parts of the U.S. earlier this year.

Artemis II stands ready for launch

NASA's Artemis II rocket stands poised at Launch Pad 39B at NASA's Kennedy Space Center in Florida. The 322-foot-tall (98 meters) Space Launch System and Orion crew capsule stack is ready to launch the mission's four-astronaut crew on a 10-day flight around the moon and back as soon as April 1.

Science in motion

Rare video shows female sperm whales working together during a birth - YouTube

Watch On

Researchers have filmed a sperm whale giving birth while being assisted by 10 other females in her social unit. It's the first time an event of this kind has ever been seen in non-primates.

The birth, captured by airborne drones in July 2023, took place over the course of an hour, during which time females surrounded the mother and newborn in a protective circle, taking turns to raise the calf to the surface — giving it time for its flukes to unfurl and acquire its own natural buoyancy control.

Sperm whale social groups are matriarchies, with life-long bonds formed between mothers, daughters, grandmothers and unrelated females. The males, meanwhile, primarily roam the oceans alone, creating one of the most extreme geographical separations between the sexes in nature.

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