What naturally occurred radiations or waves that don't produce any sound at all regardless of frequency and medium? In the video below, this person, Donald Gurnett and some other people at University of Iowa claimed to have recorded "sounds" from space. What producing those "sounds", they said, are plasma wave and radio wave. Is that real sounds afterall or is it just artificial sound produced by audio devices? But personally I don't think plasma wave, radio wave and any other EM wave produce any sound at all regardless of frequency and medium because EM radiations are much more different than sound wave.
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$\begingroup$ You thinks right. Sometimes by rays we refer to particles. In that case the idea of speed of sound might apply. $\endgroup$– AlchimistaJan 2, 2018 at 12:57
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$\begingroup$ Related: physics.stackexchange.com/q/207923/59023 and physics.stackexchange.com/q/142935/59023 . $\endgroup$– honeste_vivereJan 2, 2018 at 14:05
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1 Answer
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At 02:12 the video does clarify that these are not sounds we can hear:
"Strictly speaking, [Voyager's] plasma wave instrument does not detect sound. Instead it senses waves excited by electrons in the ionized gas (or plasma) that Voyager travels through. No human ear could hear these plasma waves."
The Voyager spacecraft plasma wave instrument is designed to operate from 10 to 56 kHz, making it sensitive to a type of longitudinal wave similar to acoustic waves. These are called ion-acoustic waves.
Actually the University of Iowa has been publishing on similar data since the late 1970's - using spectrogram plots similar to those in the linked video, above.
answered Jan 2, 2018 at 17:44
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$\begingroup$ Thanks for the responses. What naturally occurred radiations or waves that don't produce any sound at all regardless of frequency and medium? I mean even if we slowed it down using some audio instruments or using any instruments to convert it to sound, the waves still don't produce any sound whether it is audible or inaudible? $\endgroup$ Jan 3, 2018 at 23:49
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$\begingroup$ They're called ion-acoustic waves and they're moving ions and electrons in plasma, thus we can't hear them. You can read more about them in either of the latter two links provided above. If this satisfies your curiosity, please consider accepting my answer. $\endgroup$ Jan 4, 2018 at 0:13
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$\begingroup$ I'm asking what naturally occurred radiations or waves that don't produce any sound at all at any frequency, whether it is audible or inaudible, and in any medium. In your opinion, are the "sounds" that they recorded indeed produced by the ion acoustic waves or is it just artificial product resulted from data sonification? I think it is the latter. $\endgroup$ Jan 6, 2018 at 5:55
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$\begingroup$ You're right, the latter. They're being represented as sounds so that the public can be engaged more easily. $\endgroup$ Jan 6, 2018 at 8:13