Wednesday, January 10, 2007

3-D Dark Matter Map

I don't normally jump on board when big press releases come out with some new "revolutionary" astronomical discovery, and I don't normally give link dumps to what other people have to say, but when it's my former advisor whose name is being plastered all over, I can't help but say a little something. Of course, the big news was released two days ago, so I'm a little late.... Others (see Galactic Interactions and Cosmic Variance, for example) have already given nice lengthy explanations of the results. You can also take a look at the press release and the paper (subscription required). Essentially, gravity bends the path light travels in much the same way it bends the path of a thrown baseball. By looking at the distortions of faraway galaxies due to all of the intervening matter, astronomers can map out the 3-D mass distribution of the universe as shown above. (If you want a slightly more in depth discussion of what "distortions of faraway galaxies" means, you can see my earlier post on weak lensing.) This particular piece of research isn't all that revolutionary: they are using techniques that have been used before and a fairly well-established method, but the amount and quality of the data is somewhat mind-numbing. To get really high resolution data, you have to go to space, which is why the main dataset for this project is from the Hubble Space Telescope (HST). But you also need a huge area of sky for this kind of weak lensing project... and HST doesn't exactly see a lot of the sky at once, which is why this data corresponds to 575 separate pointings of the telescope.

And, oh yes, COSMOS (the multi-observatory project this research stems from) long ago won my prize for largest stretch for an acronym: Cosmic Evolution Survey?!

And since I'm playing the day-late, dollar-short bandwagon game anyhow, yes, please, I would like an iPhone (plus 2 year Cingular plan) as a gift. Thank you.

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