A Cosmic Sonogram

The Big Bang began with a burst of near-exponential expansion: cosmic inflation
Quantum mechanical fluctuations in energy made ripples in the gas
Fluctuations in radiation == Sound waves! Light as sound?!
Inflation produces scale-free perturbations leading to 1/f noise.
Cosmic redshift: Doppler shift in an expanding universe.
Hear how the fluctuations sounded a few seconds after the Big Bang.

Cosmic fluctuations can be separated from emission from our galaxy by their different spectral dependence. See the WMAP false-color maps with the dipole due to solar system motion and transformed to a frame where the dipole is removed. In these maps, CMB emission is gray-scale; foreground emissions are red. The CMB emission map is a sonogram showing the imprint of inflationary fluctuations 379,000 years after the Big Bang.