A cloud of rubidium atoms was tracked for seven seconds after researchers released it from a laser trap aboard China’s space station.

By tracking that motion in three dimensions, the team measured a record-low equivalent temperature of 9.7 picokelvin, about a quarter of the previous record.

The experiment used microgravity to produce and manipulate a Bose–Einstein condensate, a state in which atoms behave collectively as a single quantum wave.

The ability to watch the cloud expand for several seconds could give researchers more time to probe unusual states of matter and make precision measurements in orbit.

On Earth, gravity pulls atoms downward inside a trap, making them harder to hold as the confinement weakens.

Researchers can counter that pull with magnetic levitation, but doing so requires the atoms to share the same internal spin state. A trap made from focused laser beams gives researchers more flexibility over those states.

Earlier experiments found ways to give atoms a brief period of free fall. A drop tower produced the previous record of 38 picokelvin and gave researchers two seconds to observe the cloud’s expansion.

The International Space Station’s Cold Atom Laboratory reached 52 picokelvin using magnetic trapping and matter-wave lensing, with one second of free expansion.

The orbital setup gave the team a longer period of microgravity than a ground-based drop tower could provide.

The team started with around 20,000 rubidium atoms . Laser cooling slowed the atoms, and evaporative cooling removed the most energetic ones, allowing the remaining atoms to form a condensate inside an optical dipole trap.

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