This article is from Les Indispensables de Sciences et Avenir Issue 209, dated April/June 2022.
As formidable as they are, the celestial mechanics don’t make any sound. The sight of comets and their icy tails, or the sight of quasars and their powerful luminous jets, remains silent.
A sound wave is a mechanical wave that advances like a wave, through a series of compressions and stretches of the medium in which it travels, all at a faster speed because this wave is dense. In interstellar space, where the density of matter is only 0.127 particle / cm3 For about 1020 mol/cm3 On the ground there is complete silence. But NASA has converted the electromagnetic waves produced near stars into sound waves. The surprise is with go, with trails sometimes beautiful, others annoying.
Jupiter’s sharp squeak
This is how the Cassini probe revealed the song of Saturn caused by plasma waves between the planet and its moon Enceladus. Recently, the Juno probe recorded that Jupiter pierces its magnetic shield, revealing a loud whistle. Meanwhile, the Earth appears to be presenting a joyous party of sounds produced by the chorus effect, the product of electromagnetic waves emitted in the Earth’s magnetic field and struck by particles from the Sun. And now the universe is teeming with sounds!
Written by Francois Follett
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