MIT Physicists Capture Elusive 'Second Sound' Heat Waves in Superfluid Gas
• Physicists at MIT captured images of "second sound," a wave-like motion of heat, in a superfluid gas of lithium atoms • Second sound happens because in superfluids, heat propagates like a wave instead of diffusing • Hungarian-American physicist László Tisza proposed in 1938 that superfluids have "first" and "second" sounds • The team observed second sound by tracking the resonance frequencies of the lithium atoms as heat moved through them • Understanding heat propagation in superfluids could aid engineering of room temperature superconductors and physics of neutron stars