Meeting the neighbours
I wrote, just before my laptop left my life (incidentally, if you happen to be in Shepherd’s Bush with a newly acquired MacBookPro which, shall we say, fell into your hands, then I’m desperate enough to pay to have it back. Drop me an email?) a long piece about a fantastic paper released last week by some of my UCL colleagues.
They’ve produced what is being billed as the largest three-dimensional survey of galaxies across the entire sky ever to be produced. I’m a sucker for these kinds of things; there’s something special about being able to map our place in the Universe, and being able to identify exactly where in the many millions and billions of galaxies we are. The deepest survey to date - the Sloan digital sky survey - looks in detail at only a small fraction of the sky, whereas this more recent work uses galaxy positions from the 2MASS survey which covers the entire celestial sphere.
So what does our cosmic neighbourhood look like? The maps reach out 600 million light-years, and in all that space the largest supercluster is the Shapley supercluster, some 400 million light-years away. This structure is enormous, at least 20 million light-years across. Our local movements, though, are detemined primarily by the presence of the Great Attractor, around three times closer but pulling the Local Group, including our own Milky Way, toward it at the media-friendly velocity of a million miles an hour.
The maps are based on a technique which allows astronomers to infer the position of the dominant but invisible dark matter from the observed positions of the galaxies, and the next step will be to test this model by measuring the galaxies’ velocities directly. In the meantime, you can enjoy a spin around our local Universe here (large file).
Update : In response to a comment, stills are available via the RAS press release - scroll down for captions.
on October 12th, 2006 at 11:52 am
Mr Lintott -
Firstly - very interesting, informative blog - thankyou for sharing your thoughts with the wider community.
Like you, I am fascinated by the cosmos on the biggest scales. I am especially interested to see how future ‘maps’ trace out dark matter and the clues this will hopefully give us as to its role in the the universe at large.
Anyway - on to the reason for my email.
Is there a static 3D version of the 2MASS quicktime animation available.
Many Thanks
Bunny Burton-Bradford
PS
Your acquisition of a Apple MacBookPro wouldn’t have anything to do with Brian May, would it
on October 12th, 2006 at 12:05 pm
I’ve added a link to the stills - sorry for not doing this earlier.
I had my MacBookPro before Brian got his! Mind you, he has still got his so I shouldn’t be too smug…
on October 14th, 2006 at 9:21 am
Brian doesn’t seem to be too happy with his MacBookPro. Perhaps he could give it to you?
on October 19th, 2006 at 12:28 pm
[...] Having publicised the 2mass survey earlier in the month, I can’t resist posting links to a couple of other nice movies which illustrate our place in space. [...]