I just found a paper by Edward Wright (UCLA) on acoustic waves in the early universe. Allow me to ask: a. What is their frequency?, b. is there their imprint in CMb?, c. How can we model them using wave equation?
http://iopscience.iop.org/1742-6596/118/1/012007/pdf/1742-6596_118_1_012007.pdf
Our universe, 13.8 billion years ago, was just a ball of hot plasma -- a mixture of electrons, protons, and light. Sound waves shook this universe, triggered by instant, or "quantum," fluctuations happening just moments after the big bang that created our universe.
These sound waves propagated through the universe, and they left imprints on the matter and light, much like patterns made by waves on the surface of a pond into which a stone has been dropped. Even with a very high sound speed (60% light speed), the frequencies of such sound waves are incredibly low, about 〖10〗^(-12) Hz, and they only become audible to humans after an up-shift of about 50 octaves.
The spatial power spectrum of primordial sounds shows a fundamental and harmonics. The Universe acts like a resonator, with quite broad harmonics and the sound is more like a roar than a musical note.
Whereas a normal resonator is spatially bounded, the Universe is unbounded spatially but bounded temporally – it has a finite age, and the presence of harmonics is a consequence.
The “sound” of the initial landscape – the sound of that first rich silence, the so-called “Initial Power Spectrum” – was pure noise.
Our universe, 13.8 billion years ago, was just a ball of hot plasma -- a mixture of electrons, protons, and light. Sound waves shook this universe, triggered by instant, or "quantum," fluctuations happening just moments after the big bang that created our universe.
These sound waves propagated through the universe, and they left imprints on the matter and light, much like patterns made by waves on the surface of a pond into which a stone has been dropped. Even with a very high sound speed (60% light speed), the frequencies of such sound waves are incredibly low, about 〖10〗^(-12) Hz, and they only become audible to humans after an up-shift of about 50 octaves.
The spatial power spectrum of primordial sounds shows a fundamental and harmonics. The Universe acts like a resonator, with quite broad harmonics and the sound is more like a roar than a musical note.
Whereas a normal resonator is spatially bounded, the Universe is unbounded spatially but bounded temporally – it has a finite age, and the presence of harmonics is a consequence.
The “sound” of the initial landscape – the sound of that first rich silence, the so-called “Initial Power Spectrum” – was pure noise.
@Igor, Myzafere, Luca: thanks for your answers.
@Myzafere: you gave some interesting details. Allow me to ask further questions:
A. Do you think we can model these primordial sound waves using software package such as Maple? If yes, do you know good papers discussing that method?
B. are those sound oscillations similar to Sakharov oscillation? Your comments are welcome. Thank you so much
Dear Victor,
Primordial sound waves can be modeled using different appropriate software packages as Matlab, Maple or symbolic algebra program Mathematica. More details you can find in article “Coherence and Sakharov Oscillations in the Microwave Sky” by Andreas Albrecht and “BOOMERanG and the Sound of the Big Bang” by John G. Cramer (http://www.npl.washington.edu/AV/altvw104.html).
@Myzafere. Thanks for the link. I will check Cramer's paper. Best wishes
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