A physical container is not able to hold such ultra-cold matter, so Ketterle's team used magnets to contain the cloud. The spinning sodium gas cloud had a volume of one-millionth of a cubic centimeter, much smaller than a raindrop, and it developed a regular pattern of over 100 whirlpools. In the past, scientists had only observed just a few quantum whirlpools in a superfluid. This experiment was the first direct observation of this many whirlpools. The sodium gas cloud and pulsars are superfluids, which allow matter to flow without friction.
Scientists know that superfluids form quantum whirlpools when they rotate.
Quantum whirlpools reflect the smallest possible increase in rotation for the cloud or the pulsar. One might expect the two systems to behave differently since the gas cloud is 100,000 times thinner than air, while a pulsar is about ten thousand trillion times denser than air. Astronomers had observed these phenomena on pulsars but had no opportunity to manipulate them, until now. The scientists also had to figure out a way to photograph the quantum whirlpools, which were too small to see without special magnification. They switched off the magnets that were holding the gas cloud, and that allowing it to expand to 20 times its original size, making the whirlpools large enough to be photographed.