Superfluid helium in a vessel does not rotate with it as a normal fluid does. Instead, a large number of whirlpools, called vortices, are formed. They have diameters from 1000 Å to 100,000 Å. The vortices repel each other and form a hexagonal pattern. The superfluid circulates around their cores. The circulation is quantized in a way similar to that of electron orbits around atomic nuclei.
    Several types of vortex occur in ³He, depending upon temperature, rotation speed and magnetic fields. They are being studied with a rotating cryostat at the Low Temperature Laboratory in Helsinki, Finland. Such experiments have been carried out for modelling phase transitions that might have occured in the very early Universe, a fraction of a second after the Big Bang.

1 Ångström (Å) = 10^-10m