After supernova explosion sound is created....

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Discussion Overview

The discussion revolves around the nature of sound produced by supernova explosions and its implications in space, particularly regarding the medium required for sound propagation and the effects of supernova shock waves on star formation and cosmology.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants assert that sound cannot travel in space due to the absence of a medium, referencing the common phrase "in space, no one can hear you scream."
  • Others propose that while sound cannot travel in the vacuum of space, the shock waves generated by supernovae can compress interstellar gas, potentially triggering star formation.
  • One participant discusses the importance of calculating the speed of sound in cosmology, particularly in relation to the Cosmic Microwave Background (CMB) and how it relates to the size of acoustic waves.
  • Another participant introduces the concept of bow shock as a pressure wave from supernova ejecta, likening it to baryonic acoustic oscillations from the Big Bang.
  • A later reply highlights that supernova ejecta move faster than the speed of sound in the interstellar medium, suggesting that the experience of "hearing" a supernova would resemble a sonic boom, where sound is only perceived after the shock wave arrives.

Areas of Agreement / Disagreement

Participants express differing views on the nature of sound in space and its implications. There is no consensus on the interpretation of sound in the context of supernovae, as some focus on the absence of a medium while others explore the effects of shock waves.

Contextual Notes

Participants mention various factors that could influence sound propagation and its effects, such as the temperature of the medium and the role of dark matter, but these aspects remain unresolved and speculative.

Subrata Paul
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After supernova explosion sound is created... so what happens to that sound??
 
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Subrata Paul said:
After supernova explosion sound is created... so what happens to that sound??
Sound has to have a medium to travel through like air or water. There is no medium in space for sound to travel through so there is no sound. I.E. in space, no one can hear you scream.
 
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Subrata Paul said:
After supernova explosion sound is created... so what happens to that sound??
You and I owe our existence in part to the shock-waves in the interstellar medium created by supernova explosions.

They temporarily compress clouds of gas which can trigger star formation.

In a large star-forming region the explosion of one supernova can start a chain reaction of supernovas. the shock waves compress, several other stars form, some of which are massive enough to eventually go supernova themselves, they in turn make waves in the interstellar gas and plasma...
 
Subrata Paul you ask a very good question, what happens to the sound?
I think the answer is: what usually happens to sound. It travels. And its energy spreads out until it fades into background noise and becomes undetectable.

An important part of cosmology is calculating the SPEED OF SOUND in space at various times like around year 370,000
when the CMB originated because the speed of sound helps to determine the size of the acoustic waves that we see frozen in the CMB. the sound waves, called acoustic waves, are shown in density fluctuations which we detect as temperature fluctuations in the CMB.

How big the frozen sound waves look in the sky (their angular size) helps us know how far away the "surface of last scattering" was at that time in the past, and to deduce how far away it is now.

The speed of sound can be calculated if one knows the temperature of the medium. I'm not sure but I think dark matter is involved so the dark matter density may enter in. For a cloud of ordinary matter it would depend mostly on the temperature---maybe the mean free path too. Have to look this up.

Anyway it is an important thing in cosmology, and there are ways cosmologists use to calculate the speed of sound based on known conditions at various times in the past. But basically the answer to your question is "the sound travels and spreads out, and in some conditions it can trigger more star-formation"
 
In a supernova, there is a phenomenon called bow shock, which is a pressure wave carried by matter expelled during the detonation. In that sense it is the 'sound of a supernova in the same way baryonic acoustical oscillations are the sound of the big bang.
 
One key difference is that the supernova ejecta are moving faster than the speed of sound in the interstellar medium for quite a long time after the supernova, so "hearing" a supernova would be a bit like hearing a sonic boom-- you don't hear anything until the shock hits you and rattles you.
 

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