Science news this week: Astronomers close in on comet 3I/ATLAS’s origins, a strange gravity anomaly discovered off Africa and AI designs brand-new viruses

This week's science news was bursting with mind-blowing astronomical observations, led by new discoveries about the origins of the comet 3I/ATLAS.The comet, an interstellar interloper from far beyond our solar system, was first spotted in late June. Now, scientists are finally closing in on its age and where it came from. They discovered it likely originated in the far corners of our galaxy and could even be a relic from its earliest beginnings — making it potentially billions of years older than the sun.This discovery was accompanied by other observations, including the comet's unusual properties, with astronomers spotting it spewing water "like a fire hose" before it was anywhere close to the sun. Researchers are continuing to keep a close watch on the object, even deploying the European Space Agency's (ESA) Mars spacecraft to capture the closest view yet of its bright coma. You may like We also reported on astonishing astronomical discoveries made much further afield, including the first radio telescope imaging of two black holes orbiting each other, tentative evidence for controversial dark matter stars and the James Webb Space Telescope proving Einstein right eight times over with the detection of an octet of stunning gravitational lenses.Strange gravity signal inside Earth Researchers detected the anomaly in data from the original GRACE Satellites, which were active between 2002 and 2017. (Image credit: NASA/JPL)In 2007, a gravity anomaly appeared that was as long as the entire continent of Africa, occurring at the same time as a geomagnetic jerk in Earth's gravitational field.The strange anomaly's signal and the jerk lasted for about two years, but it was 18 years before they were discovered inside data collected by satellites studying Earth's gravitational field.Scientists believe the cause was a previously unknown geological process somewhere near Earth's core, likely the result of a rapid redistribution of mass in our planet's deep mantle. Yet more research is needed before scientists can understand these hidden processes and their broader impacts.Get the world’s most fascinating discoveries delivered straight to your inbox.Discover more planet earth news—Coral Triangle: The giant hidden 'Amazon' beneath the sea that appears somewhat resilient to climate change—Scientists discover gold nanoparticles hidden in spruce tree needles You may like —The Red Sea experienced 'one of the most extreme environmental events on Earth' 6 million years agoLife's Little Mysteries The site of L'anse aux Meadows, on the northern tip of Newfoundland, dates back about 1,000 years, around 500 years before Columbus arrived in the Americas. And the Native Americans were in the Western Hemisphere long before that. (Image credit: Russ Heinl via Shutterstock)Christopher Columbus was far from the first person to encounter America — in fact, when it comes to popularly-attributed discoverers of the Western Hemisphere, he was among the last.So who discovered it? Answering that question this week took us on a 23,000 year journey into humanity's prehistoric past, from Native Americans to Vikings and Polynesian seafarers, long before Europeans arrived on the continent.—If you enjoyed this, sign up for our Life's Little Mysteries newsletterAI designs new viruses As scientists design new viruses using AI, experts are investigating whether current biosecurity measures can hold up to this potential new threat. (Image credit: Andriy Onufriyenko via Getty Images)In more alarming news, we covered scientists developing an AI that built completely brand-new viruses. The viruses are bacteriophages, meaning they attack bacteria, not humans. The researchers took care to ensure their models couldn't design pathogens capable of infecting people, animals or plants.But if you're still left with the lingering feeling that this is a preamble to an apocalyptic movie, there's a risk it could be. The scientists who made the discovery tout it as having the potential to destroy antibiotic-resistant superbugs. But research elsewhere has found a number of holes and workarounds for AI models (or malevolent human actors using them) to create potentially catastrophic diseases.Thankfully, current limitations means this threat isn't immediate, but humanity's adhoc approach to AI regulation means it could happen sooner than we think.Discover more health news—Chemo hurts both cancerous and healthy cells. But scientists think nanoparticles could help fix that.—Diagnostic dilemma: A brain lesion gave a woman a lifetime of joyless laughing fits—Deadly mamba snakebites stop muscles from working — but sometimes, antivenom can send them into overdriveAlso in science news this week—Robots receive major intelligence boost thanks to Google DeepMind's 'thinking AI' — a pair of models that help machines understand the world—'Harry Potter' materials land three scientists Nobel Prize in chemistry—New species of Jurassic 'sword dragon' could help solve an evolutionary mystery—Shackleton's infamous ship 'Endurance clearly had several structural deficiencies,' new analysis revealsScience long read The first half of 2025 logged the most damaging extreme weather events in the U.S. on record. (Image credit: NOAA; Justin Sullivan via Getty Images; NurPhoto via Getty Images)Wildfires, tornadoes, heatwaves and floods: Climate change is ushering in a new era of natural disasters. In our long read this week, we investigated the economic costs of extreme weather — with more than $100 billion in damages by June of 2025 alone — along with why scientists see the trend worsening.Something for the weekendIf you're looking for something a little longer to read over the weekend, here are some of the best book excerpts, opinions and science crosswords published this week.—'The Big One' could be even worse than COVID-19. Here's what epidemiologist Michael Osterholm says we can learn from past pandemics. [Book Excerpt]—'Health impacts are being felt in real time': How the CDC is being decimated by the Trump administration [Opinion]—China issues new pledge to cut greenhouse gas emissions — is it now a global leader in climate action? [Poll]Science in motion Now is your chance to fly over a maze-like canyon on the Red Planet in a stunning new video. (Image credit: ESA/DLR/FU Berlin & NASA/JPL-Caltech/MSSS)Ever wanted to soar over an alien planet's surface? A new animation released by the ESA of Mars this week lets you do just that. Based on data from the Mars Express spacecraft, the new video takes viewers on a stunning flight over the desiccated Red Planet — from its channels carved by ancient waterways, over eroded islands, and up to a spectacular view of a gigantic asteroid impact crater.Want more science news? Follow our Live Science WhatsApp Channel for the latest discoveries as they happen. It's the best way to get our expert reporting on the go, but if you don't use WhatsApp we're also on Facebook, X (formerly Twitter), Flipboard, Instagram, TikTok, Bluesky and LinkedIn.