World first: Chinese scientists a cold atomic clock work in space

Tiangong-2 is in orbit around the Earth on this image. Credit: CMSE

Telling the time is correct is important; it is you in the morning, and coordinates everything from the air to travel to the GPS system. And if you are good enough, you can even use it to navigate in the space.

But telling the time is also a big technical challenge. Every clock in the world is incorrect to a certain extent. What technology is your watch used to mark the future ticking away in the past, that character will be imperfectly measured. Every once in a while, a fraction of a second to be lost. Even atomic clocks, which measure time by observing the ultraprecise oscillations of individual atoms and make-up in the world official timekeepers — are imperfect, that is the reason why researchers are always striving to build a bit more accurate than any built before. And now, for the first time, a team of Chinese researchers has figured out how to make one of the most accurate atomic clock technologies that are currently available work in the space.

In an article today (July 24) in the journal Nature Communications, a team of researchers from the Shanghai Institute of Optics and Fine Mechanics at the Chinese Academy of Sciences officially announced that they had successfully operated a cold atomic clock for more than 15 months in space onboard the now-defunct Chinese space station Tiangong-2. (The performance was originally reported in the journal Science in September 2017, as a version of the paper went live in the preprint journal arXiv before it went through peer review and the formal publishing process.) [Wacky Physics: The Coolest Little icles in Nature]

Cold atomic clocks, which work by laser cooling atoms to near absolute zero for the measurement of vibrations, can be more precise, because at very low temperatures, this “character” are more consistent. But actually getting the atoms to which temperatures is very difficult on Earth, let alone in the confines of a spacecraft.

Cold atomic clocks measuring the vibrations of atoms, while they are in a free fall, so that they do not interact with anything else. On Earth, that required constantly urging an atom, so that it can be measured during the fall by the detector.

Researchers have managed to atoms are ultracold in free fall before the team wrote in the newspaper. But that meant more or less tossing the experiment into the air and let him fall.

“These methods offer a microgravity environment, ranging from a few seconds (drop tower, parabolic flight) to a few minutes (sounding rocket),” they wrote in the study.

It is difficult to find such a function in a job, the researchers wrote, because it is much smaller than his colleagues on Earth, along with the safety tests that are required to start in the space, work in microgravity, protecting itself against cosmic radiation — and all without any quantum physicists on hand to make adjustments if anything were to go wrong.

But the space-bound cold atomic clocks have a number of benefits, the researchers wrote. More importantly, they can be the study of the atomic oscillations over much longer periods of time. In microgravity, the atom can remain longer, thus making for a longer period of time of the measurement.

If the Science reported in 2017, researchers with the European Space Agency (ESA) said Tiangong-2 cold atomic clock was not as accurate as it could have been. But ESA’s clock — which, in theory, would be more accurate has faced delays and has never really disappeared in the space.

Originally published on Live Science.


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