For six minutes, 150 miles above Kiruna, Sweden on January 23, 2017 floated the coldest known spot in the universe. As far as we know, the coldest anything in nature can be is absolute zero on the Kelvin scale, which is –459.67°F and –273.15°C. This postage-stamp-sized atom chip packed tight with thousands of rubidium-87 atoms was just a few billionths of a degree warmer than that. The atom chip was up there in low orbit to help a team of scientist study up-close some of the oddest, least-understood stuff there is: Bose-Einstein condensate (BEC). The team of German scientists was led by Dennis Becker of QUEST-Leibniz Research School, Leibniz University Hannover, Hanover, Germany.
Bose-Einstein condensate is the fifth-known form of matter, after solids, liquids, gases, and plasma. When atoms in zero gravity reach a temperature close to absolute zero, they cede their individuality and act as one “super-atom.” A that point, they’re tens of thousands of atoms all vibrating in sync, creating something like a blob in which the tiniest of disturbances can be detected. Scientists hope that BEC can one day be harnessed for gravitational-wave detection.
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The BEC on Earth
In 2010, scientists at the Max Planck Institute of Quantum Optics packed a cylindrical capsule about the size and width of a door with a few million rubidium atoms trapped on an atom chip, lasers, the required energy supply, solenoids, and a camera. They dropped the capsule 146 meters from the top of a tower. It fell for about four seconds, and during the zero gravity of free-fall, they remotely generated a BEC on the atom chip in less than a second. (In the lab, it takes up to a minute.) Once the BEC formed, they released the trap and the camera allowed them to see its spread as it fell. They were able to observe the BEC for a few seconds before it hit bottom.
Read more: Big Think
