You’d think the coldest spot in the universe would be some distant void between galaxies, but no—the record belongs to a lab on Earth. In 2021, scientists at NASA’s Cold Atom Lab cooled atoms to just one billionth of a degree above absolute zero. That’s colder than the Boomerang Nebula, the coldest known natural place in space. Why do this? At such low temperatures, atoms slow down so much they start behaving like waves instead of particles. This helps physicists study quantum mechanics in ways that would be impossible anywhere else.