Two years ago, a team of physicists created a stir when they reported that solid helium could flow without resistance, like a liquid utterly devoid of viscosity. Now, three different groups have confirmed the bizarre observation.

But mounting evidence also suggests the "supersolid" flow occurs only in crystals riddled with defects. In fact, one group reports that the effect vanishes if the crystal is gently heated and cooled to smooth out the flaws.

The first signs of supersolidity were spotted by Eunseong Kim and Moses Chan of Pennsylvania State University in University Park in a tiny can filled with pressurized solid helium.

Read more... (ScienceNOW)