Superfluids and Neutron Stars

The swirling vortices in BECs offer scientists an opportunity to study such processes first-hand - without burrowing into a distant star.

The possibilities don't end there: "If the condensed atoms [in a BEC were to] attract each other, then the whole condensate can collapse," Ketterle adds. "People have actually predicated that the physics is the same as that of a collapsing neutron star. So it's one way, maybe, to realize a tiny neutron star in a small vacuum chamber."

Small, confined and tame - a pet neutron star? It sounds far-fetched, yet researchers are learning to make BECs collapse in real-life experiments.

BECs are formed with the aid of magnetic traps. Carl Wieman and colleagues at NIST have discovered that atoms inside a BEC can be made to attract or repel one another by "tuning" the magnetic field to which the condensate is exposed. Last year, they tried both: First, they made a self-repelling BEC. It expanded gently, as expected. Then, they made a mildly self-attracting BEC. It began to shrink - again as expected - but then it did something wholly unexpected.

It exploded!

Many of the atoms in the BEC flew outward, some in spherical shells, others in narrow jets. Some of the ejecta completely disappeared - a lingering mystery. Some remained as a smaller core at the position of the original condensate.

To an astrophysicist, this sounds remarkably like a supernova explosion. Indeed, Wieman et al dubbed it a "Bosenova" (pronounced "bose-a-nova"). In fact, the explosion liberated only enough energy to raise the temperature of the condensate 200 billionths of a degree. A real supernova would have been 10⁷⁵ times more powerful. But you have to start somewhere.

If researchers eventually do craft miniature neutron stars, they might learn to make white dwarfs and black holes as well. Such micro-stars pose no danger to Earthlings. They are simply too small and their gravity too feeble to gobble objects around them. But such pets would no doubt be popular among physicists and astronomers.

Personally, I think I'll stick to dogs.