Hear the sound of Big Bang on the internet

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The Independent Online

The Big Bang wasn't a big bang: it was "rather like a large jet plane flying 100ft above your house in the middle of the night", according to a physicist who has recreated the noise of the universe's first moments.

John Cramer, of the University of Washington in Seattle, was prompted to do the research by an 11-year-old who wanted to know what the Big Bang sounded like 13 billion years ago.

The sounds, which can be heard on Professor's Cramer's website, www.npl. washington.edu/AV/Big BangSound_2.wav, had to be extracted from the "imprint" they left, in the form of micro-variations in the temperature of outer space. They cover the first 760,000 years of the universe's existence, when it was only 18 million light years across.

At the Big Bang, vast sound waves rippled through the indescribably hot matter that comprised the universe. The waves squeezed and stretched the matter, heating the compressed regions but cooling the less dense ones.

Even so, the sounds were so deep in pitch, Professor Cramer told New Scientist magazine, that he had to scale the frequency up by a factor of 100,000 billion. The recording lasts 100 seconds, during which the frequency of the sound falls because the waves were stretched by the universe's expansion.

"It becomes more of a bass instrument," Professor Cramer said.

The sound information was extracted as part of a project called Boomerang, which built on theoretical models that suggested the "the hypersphere of the universe rang like a bell", Professor Cramer added.

Extracting that data required a new experiment on a Nasa satellite "to see the effects of the primordial sound waves, one must look for variations in the temperature of the cosmic background radiation CBR of about one part in 10,000", according to Professor Cramer's description of the Boomerang experiment.

His work joins other studies which have found that the universe's "colour" is magnolia, based on the heat remaining in deep space.