Listen to the sound of Big Bang

A descending scream, changing into a deepening roar,
with subsequent growing hiss...

Astronomy has now been made audible, thanks to Professor Mark Whittle (University of Virginia Department of Astronomy)...

Mark Whittle:

Have you ever wondered what the "Big Bang" actually sounded like? Surely, you may be thinking, this is a trick question - didn't it just sound like, well, a really big bang? Surprisingly, perhaps, the answer is "no, not really". As is often the case with Nature, things are not so simple, and a more accurate description would be something like this: a descending scream, building into a deep rasping roar, and ending in a deafening hiss.

As if this were not impressive enough, the entire acoustic show is itself the prelude to a wonderful transformation: the highest pitch sounds ultimately spawn the first generation of stars, while the deep bass notes slowly dissolve to become the tapestry of galaxies which now fills all of space.

The birth of the Universe, it turns out, had its own primal scream.

Microwave background radiation

Modern cosmology has been busy measuring and analysing the tiny fluctuations seen in the cosmic microwave background (CMB) radiation - the omni-directional wall of hot glowing gas which dates from when the universe was only 400,000 years old. These fluctuations are often discussed by referring to their acoustic nature - sound waves move through the hot gas and are seen as peaks and troughs when they cross the glowing wall.

Most recent observations quantify the amplitudes of these waves, revealing both a fundamental tone and several harmonics, whose relative strengths have played a key role in determining a number of fundamental cosmological parameters.

This sound sequence can be loosely described as a descending scream, changing into a deepening roar, with subsequent growing hiss, nicely matching the increase in wavelengths caused by universal expansion, followed by the post recombination flow of baryons into the small scale potential wells created by dark matter. This final sound, of course, sets the stage for all subsequent growth of cosmic structure, from stars (hiss) through galaxies (mid-range tones) to large scale structure (bass notes).

Here's a sample:

The sound from the first million years after the big bang, compressed to 5 seconds (1 second per 200,000 years), and with the volume held constant. Listen...

Here's lots more: Play or download 18 sound/movie-files. 

A full explanation: Visit Mark Whittles own website...