Professor Zwirllein and his colleagues at the Massachusetts Institute of Technology (MIT) have recreated one of the possible forms of matter in neutron stars and, for the first time, traced how sound waves propagate through it.
Despite the gigantic differences in size, real neutron stars will “babble” just like a cloud of atoms in our laboratory. This sound can even be heard if you manage to approach the surface of the star somehow and attach your ear to it without being torn apart by the force of gravity.
Martin Zwierlein, one of the study authors, professor at the Massachusetts Institute of Technology
Neutron stars are the remains of large burned-out stars: after the explosion, their cores collapse into a small sphere. In this case, the matter inside the star is compressed so much that, as a result, a chain of reactions begins, during which electrons and protons merge, and the body literally becomes a ball of neutrons. However, it is not fully known what exactly neutron stars are and how they look from the inside.
To study these objects, a team of scientists from MIT recreated one of the possible forms of matter in neutron stars. To do this, they experimented with a cloud of lithium-6 atoms, which they cooled to temperatures close to absolute zero. Then they irradiated these atoms with two lasers so that they were inside a kind of light trap. Thus, atoms began to behave like particles in the liquid middle layers of a neutron star.
The researchers then tracked how the matter would interact with acoustic waves. In particular, they were interested in how the movement of sound changed the position of lithium atoms. As a result, it became clear that acoustic waves propagate through the cloud of atoms exactly as predicted by quantum mechanical calculations.
Zwirllein and his colleagues hope that their experiments’ results will help determine the structure of neutron stars and understand what types of gravitational waves they can generate.