A thermoacoustic engine takes heat energy and turns it into sound waves — and those sound waves, in turn, can be converted into other forms of energy such as electricity via transducers. My son Robin is currently working on a mechanical engineering project involving this technology. A discussion with him led me to ask:

Could a thermoacoustic engine be built using Second Sound?

To explain: "Second Sound" is the wavelike propagation of heat in superfluids like Helium II — macroscopic quantum systems near absolute zero. If a cleverly-arranged temperature gradient (or other high-entropy energy source) created (or amplified) a Second Sound signal, then one would have a Second Sound Engine.

Applications? Perhaps to power ultra-cold interstellar space probes ...

TopicScience - TopicPersonalHistory - 2007-10-11

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