NASA sends coldest place in universe into space

23 May 2018, 13:17

The coldest place in the universe is on Earth, or was on Earth. NASA has just launched it into space.

NASA's Cold Atom Laboratory (CAL) is a chamber which cools a cloud of atoms known as Bose-Einstein condensates (BECs) to a fraction of a degree above absolute zero.

Scientists have worked out that outer space never gets colder than 2.7 degrees above absolute zero (0K or -273.15C) - the temperature of the universe's background radiation.

But CAL is a box the size of an ice-chest, designed and built by NASA's Jet Propulsion Laboratory, which uses lasers and magnets to ensure atoms are cooled to within the limits of existence.

Getting matter this cold is of huge benefit to scientists because it reveals the effects of quantum mechanics, including superfluidity.

Keeping atoms this cold is not just about using refrigeration, though - it is a matter of eliminating all of the forces acting on (and thus affecting the temperature of) those atoms.

The gravity of Earth is causing NASA's Cold Atom Laboratory to warm up too much under the planet's enormous pull.

"Studying these hyper-cold atoms could reshape our understanding of matter and the fundamental nature of gravity," said CAL Project Scientist Robert Thompson.

"The experiments we'll do with the Cold Atom Lab will give us insight into gravity and dark energy - some of the most pervasive forces in the universe."

On Earth, BECs are dragged down by the pull of gravity and can only be observed for a fraction of a second.

In the microgravity environment of the International Space Station, however, the freely evolving BECs can be observed for up to 10 seconds.

As superfluid, BECs seem to have zero viscosity, where their atoms move without friction as if they were all one solid substance.

"If you had superfluid water and spun it around in a glass, it would spin forever," said aerospace engineer and project manager Anita Sengupta.

"There's no viscosity to slow it down and dissipate the kinetic energy. If we can better understand the physics of superfluids, we can possibly learn to use those for more efficient transfer of energy."