Does the Universe Expanding Make a Sound?

In summary: This same effect can be seen in sound waves, where a moving source causes the waves to stretch out and decrease in frequency, resulting in a lower pitch. In summary, the expansion of the universe does not produce sound waves that we can observe, but it does affect light waves, causing them to have a slight reddish tint when emitted from objects that are moving away from us.
  • #1
PhysicsWanabe
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Due to the doppler effect, when the source of the sound is moving away from the observer, the sound waves are spread out. Light waves also hace this effect and when a star or galaxy is moving away from us, we see the light wth a slight reddish tint. So my quesion is, does the expansion of the universe make sound waves that we can observe?
 
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  • #2
Do you know what a "SOUND" wave is and what is required to make/hear one?

I hope you do realize that one of the most proven things in physics is that in space there is no atmosphere no "air" as we would say.
Sound is nothing more than just a vibration of a medium like air that is made of matter at a certain frequency.Now you can have this vibration going on in air in water in metals and rocks and all kinds of "mediums".
In space you just don't have this medium so there can be no sound wave, because one has no place where to be.
We do have light from all parts of space , but light is a Em field and travels by it's force carrier photon which is massless and doesn't need a special medium for it to travel through.The same goes for gravity but not sound.
 
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  • #3
Crazymechanic said:
Do you know what a "SOUND" wave is and what is required to make/hear one?

I hope you do realize that one of the most proven things in physics is that in space there is no atmosphere no "air" as we would say.
Sound is nothing more than just a vibration of a medium like air that is made of matter at a certain frequency.Now you can have this vibration going on in air in water in metals and rocks and all kinds of "mediums".
In space you just don't have this medium so there can be no sound wave, because one has no place where to be.
We do have light from all parts of space , but light is a Em field and travels by it's force carrier photon which is massless and doesn't need a special medium for it to travel through.The same goes for gravity but not sound.

Thanks. And yea I know what a sound wave is.
 
  • #4
Expansion is just that. Expansion. Things move further apart over time. Nothing gets closer to anything else, and no sound or light is emitted because of this expansion.
 
  • #5
What you might be thinking of is sound as perturbation waves in the pressure field. If you adopt a more general definition of pressure, which may include the analogous pressure field in the cosmological fluid model of the universe, then you can define sound waves within the universe as acoustic oscillations of the universe's density at recombination...

This is pretty standard early universe cosmology analysis, and one of the more famous graphs comes from it:

cmb-cmbpowerspectrum.png


They are not sound waves, but they are something vaguely analogous.
 
  • #6
Drakkith said:
Expansion is just that. Expansion. Things move further apart over time. Nothing gets closer to anything else, and no sound or light is emitted because of this expansion.

But then why do we see galaxies that are belived to be moving away from us with a slight redish tint?
 
  • #7
PhysicsWanabe said:
But then why do we see galaxies that are belived to be moving away from us with a slight redish tint?

Huh? Of course they are redshifted. They are moving away from us. Would you expect something different?

EDIT: google "cosmological red shift" and "doppler red shift"
 
  • #8
PhysicsWanabe said:
But then why do we see galaxies that are belived to be moving away from us with a slight redish tint?

The light is not emitted because of expansion. It is emitted by normal means, such as hot objects like stars, or ionized gas recombining with electrons. The expansion merely causes the light waves to be stretched out and redshifted as a result.
 

FAQ: Does the Universe Expanding Make a Sound?

What is the theory behind the expanding universe?

The theory behind the expanding universe is the Big Bang theory, which states that the universe began as a singularity and has been expanding ever since. This expansion is supported by observations such as the redshift of distant galaxies and the cosmic microwave background radiation.

Does the universe expanding make a sound?

No, the universe expanding does not make a sound. Sound waves require a medium to travel through, and the vacuum of space does not have a medium for sound to travel through. Therefore, the expansion of the universe cannot produce sound.

Why do we perceive the expansion of the universe as a sound?

Some scientists have proposed that the expansion of the universe could produce a low-frequency sound wave that is beyond our perception. This is known as the "cosmic hum" and is thought to be caused by the collision of matter and antimatter in the early universe.

Can we measure the sound of the expanding universe?

Currently, there is no technology or instrument that can directly measure the sound of the expanding universe. However, scientists can indirectly study the effects of the cosmic hum through observations of the cosmic microwave background radiation and other astronomical phenomena.

Will the sound of the expanding universe ever reach us?

No, the sound of the expanding universe will never reach us because it is traveling through a vacuum, which does not allow for sound waves to travel. Additionally, the expansion of the universe is happening at an accelerating rate, so the sound waves would never catch up to us even if they were able to travel through space.

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