THE UNIVERSE MOVES TOWARDS BASS

from Reuben's Zoo Station:

Not with a bang, but a hum
The New Scientist is carrying a report on an analysis done on the leftover radiation from the Big Bang. Turns out it wasn't a bang as much as it was a hum.

To produce the sound, Physicist John Cramer of the University of Washington in Seattle took data from NASA's Wilkinson Microwave Anisotropy Probe. Launched in 2001, the probe has been measuring tiny differences in the temperature between different parts of the sky. From these variations, he could calculate the frequencies of the sound waves propagating through the Universe during its first 760,000 years, when it was just 18 million light years across. At that time the sound waves were too low in frequency to be audible. To hear them, Cramer had to scale the frequencies 100,000 billion billion times.

The loudness and pitch of the sound waves reflect what happened in the early Universe. During the 100-second recording, the frequencies fall because the sound waves get stretched as the Universe expands. "It becomes more of a bass instrument," says Cramer.  ¶ 6:53 PM