March 24, 2004


A few days ago David Whittle (see 17th March) emailed me to say that he'd converted a power point presentation on the sound of the early universe into a web page. I looked at it on my mac but the sounds wouldn't play. Here in the astrophysics department I've tried it on a windows machine and, lo and behold, it works.

(This mac/windows incompatibility is really annoying : looking at this site on the same windows machine none of the movies play, infact looking at the prescribed file types for the windows media player it's hard to see what file types the two different platforms have in common . . . it seems .mpg should work but my movie exporter doesn't do .mpg . . . . )

Listening to David's sounds and reading his approach to creating them is very interesting. Most sound like noise, weighted towards various frequencies depending on the size of the universe / interpretation of data, which is kind of like I'd expected. Very different from John Cramers sound (17th February). More like the Cramer interpretation is a sound created by simplifying the data down to just the peaks in the power spectrum, giving a more harmonious combination of frequencies.

Pedro's getting into this - he's slowly turning into a sound artist ! - now full of ideas as to alternative ways of interpreting the data and experiments with low frequencies to create localised spaces of silence and loudness where waves cancel each other out / reinforce each other, a la wave interference patterns.

The cmb sounds are really low - in the region of 48 to 54 octaves below middle c. That's wavelengths of between 20,000 and 200,000 light years.

Another thing Pedro is asking is what size would the universe have to be - or have been - for these frequencies to be in the audible range, starting around 60 hz. A rough calculation suggests a volume similar to that of the earth.

Posted by Jem Finer at March 24, 2004 5:34 PM