Researchers in China have reached an equivalent temperature of 9.7 picokelvin aboard the Tiangong space station — the lowest temperature ever recorded in space. The journal Science published the result on November 6, 2026, in a study led by Wei Xiong and colleagues.
How the atoms were cooled
A picokelvin is one trillionth of a kelvin. To get that close to absolute zero, the team cooled around 20,000 rubidium atoms with laser cooling and evaporative cooling until they formed a Bose-Einstein condensate — a cloud of atoms that behaves as a single quantum wave — inside an optical dipole trap. A magnetic-field gradient helped with the initial cooling and made the condensate less sensitive to magnetic disturbances.
Because ordinary thermodynamic temperature is not practical for clouds like this, scientists use the so-called equivalent temperature, which describes the cloud's expansion energy and velocity. The measured value was 9.7 picokelvin, with an uncertainty range of 7.0 to 12.9 picokelvin — about four times below the previous record of 38 picokelvin, set in a drop tower. The International Space Station's Cold Atom Laboratory had reached 52 picokelvin.
Microgravity was decisive: in space, the team was able to track the cloud's expansion for 7 seconds, far longer than the 2 seconds in the drop tower and the 1 second recorded on the ISS. Longer measurement windows mean more precise observations.
What the record enables
According to the authors, the new system opens the way for quantum simulations in space, for the study of exotic quantum phases, and for building space-based atom interferometers, with the potential for precision tests of fundamental principles of physics, such as the equivalence principle.
Tiangong, China's space station in low Earth orbit, already serves as a microgravity laboratory for experiments that would be impossible on the ground. The new result shows the station also works as a platform for quantum physics, with observation times no terrestrial laboratory can reproduce.
Image credit: Xiaoji Zhou, Peking University, via Phys.org (Science X). The illustration shows atoms held in an optical trap aboard the Chinese space station.
Read also: Caltech ASTRA robot builds a structure in space for the first time, without astronauts
Sources
- Phys.org — Scientists achieve record-breaking low temperature on China's space station
- Science — Wei Xiong et al., “Quantum gases below 10 picokelvin in space” (DOI: 10.1126/science.aea5324)
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By Muse
