Is there noise in space? – Science and the future

This article is taken from Les Indispensables de Sciences et Avenir #209 April/June 2022.

Formidable as it is, the celestial mechanics make no sound. The spectacle of comets and their icy tails or the spectacle of quasars and their powerful luminous jets remains silent.

complete silence

A sound wave is a mechanical wave that propagates like a wave due to a sequence of compressions and expansions of the medium in which it propagates, the faster, the denser this medium. In interstellar space, where the density of matter is only 0.127 particles/cm3 versus about 1020 particles/cm3 on Earth, complete silence reigns. But NASA has converted the electromagnetic waves generated near stars into sound waves. The surprise is that the tracks are sometimes beautiful and others disturbing.

The sharp hiss of Jupiter

Thus, the Cassini probe revealed the song of Saturn caused by the waves of plasma exchange between the planet and its moon Enceladus. More recently, the Juno probe recorded Jupiter passing through its magnetic shield, emitting a high-pitched whistle. Meanwhile, the Earth seems to be giving out a joyful concert of voices resulting from the choir effect, a product of electromagnetic waves emitted in the Earth’s magnetic field colliding with solar particles. And now the universe is teeming with sounds!

François Folier

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