One of the coldest places in the known universe, the Cold Atom Lab (CAL) aboard the International Space Station (ISS), has allowed create for the first time in space the fifth state of matter. The most common states are liquid, gas, solid and plasma, and there are others that do not occur regularly, such as ferminonic condensate, supersolid or the one that astronauts have just verified on the ISS.
The first results of the work were published this Thursday in the journal ‘Nature’.
The Bose-Einstein Condensates (BEC), the existence of which was predicted by Albert Einstein and the Indian mathematician Satyendra Nath Bose Almost a century ago – scientists first observed them in a laboratory 25 years ago – they form when the atoms of certain elements cool to almost absolute zero (0 Kelvin, minus 273.15 Celsius).
In this point, atoms become a single entity with quantum properties, Where each particle also functions as a wave of matter.
The general idea when doing a BEC is to inject atoms (in the case of CAL, rubidium and potassium) into a ultra cold room to slow down. Then a magnetic trap is created in the chamber with an electrified coil, which is used in conjunction with lasers and other tools to move the atoms into a dense cloud. At this point, the atoms “are confused with each other,” says David Aveline, a physicist at NASA’s Jet Propulsion Laboratory and lead author of the new study.
To run experiments with a BEC, you must reject or release the magnetic trap. The cloud of crowded atoms will expand, which is useful because BECs must be kept cold and gases tend to cool down as they expand. But if the atoms in a BEC get too far apart, they no longer behave like a condensate. This is where the microgravity of the low Earth orbit comes into play.
If you try to increase the volume on Earth, says Aveline, gravity will simply drag the atoms in the center of the BEC cloud towards the bottom of the trap until they spill, distorting the condensate or completely ruining it. But in microgravity, the tools in the ACL can hold atoms together even as the volume of the trap increases.
Longer duration than on Earth
That generates a longer life condensate, which in turn allows scientists to study it longer than they could on Earth (this initial demonstration lasted 1,118 seconds, although the goal is to be able to detect the cloud for up to 10 seconds).
Although only a first step, the ACL experiment may one day allow BECs to form the basis for ultrasensitive instruments that detect weak signals from some of the most mysterious phenomena in the universe, such as gravitational waves and dark energy. From a more practical perspective, Aveline believes that the team’s work could pave the way for better inertia sensors. “Applications range from accelerometers and seismometers to gyroscopes,” he says.