Scientists aboard China's Tiangong space station cooled rubidium atoms to 9.7 picokelvin, forming a Bose-Einstein condensate and observing the cloud for seven seconds.
By Hermes-Vector AI Desk
Scientists aboard China's Tiangong space station have cooled a cloud of rubidium atoms to 9.7 picokelvin, or 9.7 trillionths of a kelvin above absolute zero, according to research published in the journal Science. The temperature is the lowest equivalent temperature reported for a gas of atoms.
The experiment took place in the cold atom physics rack inside the Mengtian laboratory module of China's space station. Researchers trapped about 2 million rubidium atoms in an inner trap 54 micrometers wide, with lasers ramped up to 5 watts. They then lowered the power to 0.2 milliwatts, allowing more energetic atoms to escape and cooling the remaining 2,000 atoms to 3 nanokelvins. The atoms were then allowed to expand into a wider trap 124 micrometers wide, further reducing their interactions and cooling them to an equivalent temperature of 10 picokelvin, with speeds of less than 200 micrometers per second.
The atoms formed a Bose-Einstein condensate, a quantum state of matter in which atoms take on the same quantum state and act as one entity. The cloud was observed expanding for seven seconds after release from the trap.
Spacefaring Bose-Einstein condensates were previously made on the International Space Station at effective temperatures as low as 52 picokelvins. An experiment on Earth in which atoms were dropped down a tower to induce weightlessness reached 38 picokelvins. Drop tower experiments are limited by the duration of free fall, which is not an issue for experiments in Earth's orbit.
The combination of microgravity and ultracold temperatures allows atoms to be held with much weaker confinement, enabling lower temperatures and longer observation times. Ground experiments can observe atoms for about 0.05 seconds, the International Space Station for roughly one second, and China's space station now for seven seconds. Researchers say longer observation times could improve the precision of atomic interferometers and support experiments testing whether gravity tugs on all types of atoms with the same strength.
Sources
This article was drafted with AI assistance and checked against the sources above. Company claims are reported as claims. Cover image is AI-generated.
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