Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Gibwitch on 06/02/2009 00:30:03
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Gibwitch asked the Naked Scientists:
How do we know that the big bang made a sound? isn't space a vacuum?
What do you think?
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"Big Bang" itself is a misnomer. There would have been no sound.
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Let us put it this way Gibwitch:)
All waves can be played as sound.
It's not really the 'source' that matter, more the receptacle.
We do seem to have an imprint of the BB on our sky.
And in the form of 'waves'.
So yes, it will be able to be made into sound.
http://www.iht.com/articles/2005/01/12/news/bang.php
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Uup ooh; now we've unleashed the Pandora's Box. Now we're gonna have the Big Bang Code; all that great wisdom and stuff that must be stored in those ripples and structures that came from the early Big Bang [:o]
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Sound in what sense?
Sound is the temporary variation of density in a medium. It doesn't need to be regular or have a frequency but just needs to be a variation from the nominal density. Now an important thing to remember about the Big Bang is that you could only exist inside it - you couldn't observe, or 'listen' to it from outside. Baring this in mind, and as long as we're talking about the BB before the point where it became transparent, it would have acted as an opaque solid/fluid medium, so yes; it would have been theoretically possible to hear the BB. Looking at the way it's all turned out, you might have heard a little bit of 'white' noise resulting from whatever caused the slight variations visible today in the CMBR overlaid on something that was more like a weather pressure-front, with a huge dynamic range and constantly reducing frequency (due to the expansion), than a sound.
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Seems the Sun is singing (http://www.nsf.gov/news/news_summ.jsp?cntn_id=109588). Maybe the Big Bang was singing too [:)]
Sound waves escaping the sun's interior create fountains of hot gas that shape and power a thin region of the sun's atmosphere which appears as a ruby red "ring of fire" around the moon during a total solar eclipse, according to research funded by the National Science Foundation (NSF) and NASA.
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"I understand that sound cannot be heard in space. Was there another kind of wave created during the Big Bang? Would it still be traveling through space? How would it register? And how would it dissipate if there is no "end" to space?
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A sound wave in air is simply a sequence of compressions (higher than normal density) and rarefactions (regions of lower than normal density) which propagate through the air at the speed of sound (compressions like to expand because of their higher pressure, the rarefactions like to get smaller -- the result is a propagating wave).
If the sound waves are of the correct wavelength, we hear them as ordinary sound -- shorter ones are perceived as having higher pitch. If the waves are too short or too long in wavelength, we cannot hear them, but they are still called sound waves. Any gas can support similar waves.
Such waves were present in the Big Bang. A big part of the pressure of the gas was the radiation (seen as microwaves) and these determined the sound speed. Early in the expansion, the density of the gas became low enough that the radiation could no longer see it, to communicate its pressure to the gas. At this point, the sound no longer propagated and the microwave radiation retained the imprint of the sound at that epoch. The various wavelengths seen in the microwaves tell us about the physical conditions early in the Big Bang. We would not hear these waves as sound.
A place to read more about this is on the WMAP mission website. You might want to explore this site further for more information on the cosmic microwave background radiation.
Dr. Randy Jokipii
(January 2006)
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The 'Big Bang' was a term coined by the late great Sir Fred Hoyle who should have been awarded the Nobel but shamefully, to the Swedish Academy of Sciences' discredit, wasn't. But Fred wasn't a proponent of Big Bang Theory, in fact he bitterly opposed it, advocating rather the Steady State Theory where matter was constantly being created, which accounted for an observed expansion of the universe.
Ironic that Fred coined 'Big Bang' as a term of ridicule and derision when now it's the accepted term by cosmologists and the public alike for a theory of origins, consistent with most observations, especially the cosmic background radiation referred to in these pages.
Interestingly, the Big Bang wasn't big and it didn't go bang. In fact it was pretty much over, which is to say its destiny was writ in stone as it were, when the primordial universe was not much larger than a grapefruit.
Intuitively I would think an observer, receptive to all possible audio frequencies, within a Big Bang event would find it a reasonably hostile environment as far as ambient noise is concerned. To paraphrase, find me a noisier place. An observer outside of a Big Bang event is beyond definition as there is no space or time or place or any set of events within which an observer can exist there. There is no there there...
And the Nobel? Well, Fred described the processes that created the heavy elements, nuclearsynthesis, within stars, and how these elements were flung about space by stellar events including supernovae, eventually forming other stars, planets, moons, comets, oceans, people, peacocks and popcorn. A heroic achievement.
That Fred was denied a Nobel after discovering the origins of the stuff we are all made of is truly lamentable.
He was not without some controversy and was fearless in challenging accepted wisdom in many disciplines beyond his native physics, astronomy and mathematics. One idea he developed was 'panspermia', the theory that life arrived on Earth and elsewhere from space; from comets and other interplanetary and interstellar debris. Well, you can imagine how he was mocked in his time. Yet, with recent discoveries on Mars, and the discovery of hundreds of ex-solar planets around neighboring stars, the idea of panspermia is looking increasingly less ludicrous these days.
To conclude. I'm not sure if the Big Bang was audible or not. But if it was audible there is a good chance that, if Fred Hoyle was around, you wouldn't hear it. Fred's noise was louder. [:)]
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I totally agree Democritus, but neither life, nor the Swedish Academy of Sciences' is spot less:)
They both have 'blemishes' and that is one of them.
One should also notice that he wrote one of the best Science fiction I've had the pleasure to read.
http://en.wikipedia.org/wiki/The_Black_Cloud