Helium Crystals Grown in Zero Gravity

Physics On a Plane Helium Crystals Grown in Zero Gravity :

A group of physicists in Japan have taken to the skies to grow crystals in zero gravity.

The presentation of the results at the Institute of Physics of the Journal of the German Physical Society of New Physics, who have overcome the limitations of the laboratory to examine the peculiar dynamics of helium crystals on a scale much larger than can be achieved with ordinary materials.

Their findings could help researchers reveal the fundamental physics behind the formation of crystals, while also presented the phenomena that are hidden by gravity.

Helium crystals were grown using high pressures, extremely low temperatures (0.6K/-272 ° C) and spray with a superfluid - a quantum state of matter that behaves like a fluid but has a zero viscosity of meaning, which have complete resistance to stress. Superfluids can also flow through very small holes without any friction.

Lead author of the study, Professor Ryuji Nomura, the Tokyo Institute of Technology, said: "The Helio crystals grow very quickly in a superfluid helium atoms because they are made by a superflow fast, so it can not hinder crystallization process has been ideal material. for the study of basic questions of the form of crystals, because as the crystals are formed rapidly".

"It may take thousands of years for the classical normal crystals to reach their final form, however, at very low temperatures helium crystals can reach their final form in a second helium When crystals grow more than 1 mm can be easily deformed by gravity. therefore, we did our experiments on a plane. "

The experiments were conducted in a small plane, in cooperation with the Agency Japan Aerospace Exploration Agency (JAXA). When a specific route, known as parabolic flight, the jet supplied zero gravity conditions for 20 seconds. About eight experiments were carried out over a two-hour flight.

A specially designed mini fridge was taken aboard the aircraft, which was equipped with windows to crystal formation can be observed. Large crystals of helium were placed in the bottom of a high pressure chamber, and with a sound wave after zapping to crush into small pieces, which were then sprayed with a superfluid helium-4. Once crushed, the smaller crystals melt and rapidly grew larger until only one 10 mm glass survived.

The crystal grew under a process known as Ostwald ripening. This is commonly seen on the ice when it gets hard and crunchy as you age - large ice crystals begin to grow at the expense of smaller ice crystals.

"Ostwald ripening is often a very slow process and has never been seen in these enormous crystals in a very short period," continued Professor Nomura.