FlashFeed

If you push two metal plates together on Earth, nothing happens. But if you take those same plates into the vacuum of space, they can fuse into a single piece of metal. This phenomenon, called cold welding, has been a known hazard for spacecraft engineers for a long time. So what's actually happening at the atomic level, and why does space make it so much easier?The answer comes down to a lack of oxygen in space, experts told Live Science.Sign up for our newsletter(Image credit: Marilyn Perkins / Future)Sign up for our weekly Life's Little Mysteries newsletter to get the latest mysteries before they appear online.Metals are made of lattices — structures where atoms are bonded to one another. But atoms near the surface of a metal aren't bonded to anything on the outward-facing side. If given the chance, they'll "reach out" and share electrons with the surface of another piece of metal. But on Earth, nearly every metal surface is coated in an oxide layer. The layer is just a few atoms thick and forms when metal meets oxygen. "Once the oxide is formed, it's over," Julia Greer, a materials scientist at Caltech, told Live Science. "Then it can't cold weld anymore, because the oxygen basically passivates these bonds."That thin oxide acts like an insulating wrapper. Without it, the free electrons at the surface of one metal piece stop recognizing which atom they belong to. "Those electrons don't know if it's in this piece or if it's in that piece, so they begin sharing the electrons, and essentially that cold welds things together," Sven Bilén, a professor of engineering design and aerospace engineering at Penn State, told Live Science.In space, there's no oxygen to rebuild that layer once it's gone. The cold and the radiation make things worse. Bombardment from solar and ionic radiation in orbit can scour metal surfaces clean, Greer said, leaving freshly exposed atoms primed to bond. "Everything in space is conducive to cold welding," she said.Metal surfaces are never perfectly smooth, either. At a microscopic level, they're jagged ‪—‬ more like tiny mountain ranges than flat plains, said Zachary Cordero, an aerospace engineer at MIT. Pressing two surfaces together, especially with any sliding or vibration, can shear off the oxide layer that formed while the metal was on Earth and flatten those peaks into metal-to-metal contact. "You're breaking up the surface oxide, and you're forming metallurgical bonds," Cordero said.Why cold welding worried early spacecraft engineersCold welding in space has long been a problem. "If there is cold welding, things can become stuck in place," Cordero told Live Science. "If you have a deployable structure and there's cold welding, you might freeze the mechanism, or a door might become locked, or something might become immobilized, which you don't want." For example, say you were to add a metal screw to a metal door. After a while, you would not be able to unscrew it because it would have become part of the door.Bilén pointed to NASA's Galileo probe, which launched in 1989: lubricant loss and launch vibrations during launch are thought to have stripped the oxide layer from parts of its furled high-gain antenna. When engineers attempted to deploy the antenna in 1991, it never fully opened. An illustration of NASA's Galileo spacecraft, whose high-gain antenna never fully deployed during its journey to Jupiter. The failure is widely attributed to cold welding. (Image credit: MARK GARLICK/SCIENCE PHOTO LIBRARY via Getty Images)Some metals are more troublesome than others. Gold and platinum don't form an oxide layer at all, even on Earth, which makes them notoriously prone to cold welding. "Gold definitely is a very notorious metal for cold welding," Greer said, adding that gold's softness lets it conform easily to whatever surface it touches and it bonds even more easily.How to prevent cold welding in spaceTo prevent components from accidentally fusing in orbit, engineers rely on a few strategies. One is anodizing, a process that locks an artificial oxide layer onto a metal surface. Another method is to coat moving parts with dry lubricants, such as molybdenum disulfide, to physically keep surfaces from touching.Related mysteriesCan other metals be turned into gold? Why doesn't stainless steel rust?How do tiny pieces of space junk cause incredible damage?A third strategy is to pair dissimilar metals — for instance, gold next to a "body-centered" metal, like molybdenum — so their atomic structures don't mesh as neatly. "Their packing order is not quite perfectly aligned, and so there'll be a lot more energetic kind of barrier to overcome," Greer said. Before launch, hardware also gets shaken on vibration tables and cycled through extreme hot-and-cold swings inside vacuum chambers, simulating the stresses of liftoff and orbit to catch problems on the ground.Even with all of those precautions, cold welding can still happen. Bilén recalled bolts in his own lab's vacuum chamber fusing shut after a move across campus. They eventually had to be drilled out. "It happens even on Earth," he said.See how much you know about human exploration into space with our spaceflight quiz!

UK is latest country to set minimum age for social media access but big tech is fighting back globally against curbsSocial media bans go global: big tech faces a reckoning after Australia’s crackdownArturo Béjar, a former employee turned whistleblower at Mark Zuckerberg’s Meta, has talked to parents around the world. He says they share the same perspective: they dread the day their children are old enough to go online.Governments appear to be listening too. This month the UK became the latest country to state that it would set a minimum age of 16 for accessing major social media platforms. Social media bans are becoming a legislative trend after the precedent set by Australia last year, when it imposed an age limit on platforms including Meta’s Instagram and Facebook, Google’s YouTube, Elon Musk’s X, TikTok and Snapchat. Continue reading...

Swaptopus plans battery hubs capable of supporting 300,000 electric trucksCATL and Octopus want truck batteries swapped within minutesEurope's freight sector could avoid lengthy charging delays through swappingOctopus Energy has outlined plans for large-scale battery projects aimed at accelerating the shift towards electric freight transport across Europe.The company is working with battery giant CATL on battery technologies for freight transport, energy storage, and grid services.While the immediate focus falls on commercial transport infrastructure, the partnership could eventually help bring battery swapping into the mainstream European trucking market.Battery swapping takes priority before household storageOctopus and CATL have formed a joint venture called Swaptopus to expand battery swapping infrastructure throughout European freight networks.Instead of waiting for charging sessions to finish, electric lorries will exchange depleted battery packs within a matter of minutes.CATL's largest commercial vehicle batteries can reach 1000 kWh, roughly 20 times the capacity found in an average electric passenger car."Electric trucks already beat diesel on running costs, the challenge is keeping them moving. Battery swapping changes that. Instead of waiting for hours, trucks can be back on the road in minutes,” said Greg Jackson, CEO and Founder of Octopus Energy Group.“By combining Octopus’s software and energy expertise with CATL’s world-class battery technology, we’re making clean freight practical at scale across Europe."The first large battery swapping hubs are expected to begin operating during 2027, beginning with sites located within the UK.Octopus and CATL intend to increase that network to more than 30 large hubs operating throughout Europe by 2035.According to figures released alongside the announcement, the infrastructure could eventually support more than 300,000 electric trucks.The companies also estimate the project could unlock more than £30 billion in private investment over the coming years.Vehicle-to-Grid plans could support future batteriesBeyond freight transport, both companies are also examining energy storage technologies and wider electricity management opportunities across Europe.One proposal involves expanding Vehicle to Grid technology across CATL's global network of automotive manufacturing partners and customers.The companies believe millions of future electric vehicles could eventually return electricity back into national energy networks during demand peaks.“Battery swapping will be a significant part of the future of commercial transport. We have field-proven this technology in China, and we are delighted to bring it to the UK and Europe…” said Dr. Robin Zeng, Chairman and CEO of CATL.“Together, our expertise in battery swapping, B2G (Battery-to-Grid) and energy storage, paired with Octopus’s AI-powered energy trading and management technologies, will speed up the electrification of road transport across the region.”Swaptopus believes battery swapping hubs could eventually serve purposes extending well beyond keeping electric trucks on the road.“We believe the future of land based transport is electric and autonomous, and battery swapping is a massive part of the enabling infrastructure,” said William Rowe, CEO and Founder of Swaptopus.“Not only does it significantly reduce down time but since the batteries at the swapping stations can be charged and discharged when the grid needs it, they act as a virtual power plant and in turn lower costs for consumers.”