Thursday, January 22, 2009

Cosmic microwave background hat

Hi again folks.
So, today an old idea which I'm just about getting around to planning seriously now. This started with a discussion here about the big bang and background radiation(or more accurately, a whole bunch of helpful geeks helping me with physics - thanks folks!).
So, science, and a quick recap of background radiation. According to the big bang theory, in the early days the universe was very hot, and full of light. As it expanded and cooled, this light has lost a lot of energy, but it should still be there. This is called "cosmic microwave background" radiation. The stories of early experiments into detecting this are quite famous, but the upshot is it was detected experimentally, and as I understand it, is some of the hardest experimental evidence for the big bang. Lots more cool information at Wikipedia.
In the 1990s, the COBE satellite made some very precise measurements of the energy of this radiation, and found that in fact it varies(though not by much). The thinking is(well, was, back when I kept up with popular science) that these variations would be caused by tiny variations in the very early universe, which would grow larger as it expanded and these tiny variations would lead to the formation of galaxies and stars. So these variations are very important - they could well be responsible for the entire structure of the universe we see today. Since then there have been more accurate probes, particularly WMAP, which just gave some new measurements last year. And what better way to celebrate all of this than with a hat?

So the plan is this - to take one of the images produced by the COBE probe(WMAP is more accurate, but I think the resolution is too high for my purposes), chart up the data and using stranded knitting, knit it into a hat. Possibly making up a few over the top lines about how this hat contains the pattern for the universe along the way. The main difficulty is drawing a chart of the right kind, which is mostly a question of manipulating images to make a nice grid in polar coordinates. (That said, other people seem to have done this much better, than me as you can see here).

So yep, that's the plan. Perhaps I should write "COBE" on it too, so people will realise it's not just a splodgy coloured hat.
Happy knitting!

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