THE coolest thing in the universe is officially a small cloud of sodium atoms in a laboratory in Cambridge, Massachusetts.
Physicists there have chilled 2500 sodium atoms to within half a billionth of a degree of absolute zero. “Nothing in the universe [we know of] is naturally this cold,” says Aaron Leanhardt, who led the research. Even deep space exists at a temperature 6 billion times higher.
To cool the atoms, the team from the MIT-Harvard Center for Ultracold Atoms trapped them with magnetic fields, then allowed the gas they form to slowly expand. The result breaks the Guinness World…
