Plate Nº 46 · recorded November 9, 2026
PhysicsReported finding
Tiangong cools atoms to a record-low temperature in space
Researchers on China’s Tiangong space station cooled 20,000 rubidium atoms to about 10 picokelvins, forming a Bose-Einstein condensate colder than any previously reported.
By Elena Vasquez3 min read673 words
In brief
- Researchers cooled 20,000 rubidium atoms to about 10 picokelvins, or 10 trillionths of a kelvin, aboard Tiangong.
- The result was reported in Science on November 5 and described as colder than any previous Bose-Einstein condensate.
- Laser-based traps reduced the atoms’ motion in microgravity, where Earth’s sagging effect on atom clouds does not apply.
- Previous space-station condensates reached 52 picokelvins, while an Earth drop-tower experiment reached 38 picokelvins.
- Scientists can use such condensates to test the equivalence principle, which says objects of different masses fall at the same rate in a vacuum.
By Elena Vasquez
Researchers on China’s Tiangong space station cooled 20,000 rubidium atoms to about 10 picokelvins, a record-low temperature for a Bose-Einstein condensate.
The team reported the result in Science on November 5. The report described the condensate as “colder than any before,” though it gave the temperature only as an approximate value without an uncertainty range in the material summarized here.
How cold is 10 picokelvins?
Ten picokelvins equal 10 trillionths of a kelvin. That is barely above absolute zero, which equals −273.15 degrees Celsius. At the atomic scale, temperature reflects motion: atoms and molecules in the air around us move more slowly when they are colder.
For a cold-atom system, researchers can determine an effective temperature from how slowly the atoms spread when the trap releases them. The lower the effective temperature, the slower the expansion. In this experiment, the rubidium sample reached about 10 picokelvins.
The practical takeaway is simple: the Tiangong sample was colder than earlier condensates on the ground or in orbit.
Why did the experiment need space?
Researchers used laser-based traps to contain the 20,000 rubidium atoms and reduce their motion, which cooled the sample. The atoms orbited Earth aboard Tiangong. Gravity remains active there, but the station and its contents fall together, creating microgravity, the apparent weightlessness of an object in free fall.
On Earth, gravitational forces make clouds of atoms sag. That sag reduces how effectively scientists can cool the cloud. In microgravity, the atoms do not experience the same Earthbound sagging, which lets the experiment push their motion to exceptionally low levels.
The advantage is duration. Researchers can imitate weightlessness on Earth by dropping atoms down a tower, but that works only during the tower’s brief free fall. An orbiting station does not face the same time limit.
In plain terms, space gave the researchers a longer, steadier path to colder atoms.
What is a Bose-Einstein condensate?
A Bose-Einstein condensate starts as a disordered collection of atoms. After enough cooling, the atoms take on the same quantum state and act as one entity rather than as a disorderly group of separate particles. A quantum state is the specific physical condition an atom occupies; sharing one state lets the group behave collectively.
Ultracold atoms give scientists a way to study exotic states of matter and other fundamental physics. They can also test ideas such as the equivalence principle, which says objects with different masses fall at the same rate in a vacuum.
The condensate therefore gives researchers a way to examine quantum behavior that is hard to study under ordinary laboratory conditions. Its value lies in providing access to matter near absolute zero, where collective quantum behavior becomes the experiment’s focus.
In plain terms, the experiment turns a cooling record into a platform for testing unusual physics.
How does the record compare?
Spacefaring Bose-Einstein condensates had previously reached effective temperatures as low as 52 picokelvins aboard the International Space Station. A ground-based experiment dropped atoms down a tower to induce weightlessness and reached 38 picokelvins.
The Tiangong result, at about 10 picokelvins, was colder than both benchmarks. It also avoided the tower experiment’s central constraint: the end of a short free fall.
Previous work showed that researchers could create these condensates in orbit and briefly reproduce weightlessness on Earth. The new lower temperature shows the benefit of combining laser cooling with microgravity for longer.
In short, 10 picokelvins beats 38 and 52 picokelvins, with orbital microgravity supplying the key advantage.
What does the temperature claim cover?
“About 10 picokelvins” is an effective-temperature measurement for the cold atoms, based on their expansion after release. It is not a claim that Tiangong itself, or its equipment, operated at that temperature. The summarized report provides no numerical uncertainty, so the record should not imply a more precise result than the reported figure supports.
In plain terms, the number describes the sample’s ultracold state, with the precision the report actually provides.
via sciencenews.org (Source)
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Correspondent covering money, funding and market shifts around general science news at SciBeat.
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