Cosmic Cartography: Here Is Your (Local) Universe
June 17, 2013 | 
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Our local cosmic terrain (Credit: Helene Courtois)
A new video tours the nearby universe and makes it charmingly familiar.
When I was a graduate student I spent a lot of time studying maps of our universe. These were being constructed using great surveys of galaxies. Each of these fuzzy specks was triangulated on the sky and located in depth by its apparent recession velocity – the phenomenon of universal expansion first measured by astronomers like Edwin Hubble back in the 1930′s. One of my favorite references was an atlas published, rather unusually, in book form by Brent Tully and Richard Fisher in 1987. This took the dry tabulations of galaxy positions and apparent distances and made them into pictures, real maps, with regions and features labeled and made familiar.
I still have it:
The Nearby Galaxy Atlas (Tully & Fisher, Cambridge University Press, 1987)
Here, for example, are positions of our neighboring galaxies towards the northern galactic pole:
Galaxies fit for an ancient explorer...
It was a rather bold thing to do, to produce these maps, since we knew that our knowledge was still very limited. But what a marvelous thing, to be able to hold an atlas of the universe in your hands!
Time moves on, and now surveys like the great Sloan Digital Sky Survey, or the 2dFand 6dF projects, have fleshed out and extended these earlier efforts by astonishing factors. But there is still something deeply moving about charting out our cosmic neighborhood, whether its really a backwater or a main street. It’s our place in the vastness of nature, and in that sense it will forever be unique.
This new video tour, the ‘Cosmography of the Local Universe‘ by Helene Courtois et al. gathers together our current atlas in a charming and fascinating tutorial.
It’s well worth the 17 minutes to feel a little like a cosmic mariner. And in case you wonder how ‘local’ is local? This map encompasses galaxies up to around 400 million light years from us…
It’s well worth the 17 minutes to feel a little like a cosmic mariner. And in case you wonder how ‘local’ is local? This map encompasses galaxies up to around 400 million light years from us…
A better quality (to HD) video is also available here:
For more information check out the project page and the link to the preprint of the scientific article to appear in the Astronomical Journal, by Helene M. Courtois, Daniel Pomarede, R. Brent Tully, Yehuda Hoffman, and Denis Courtois.
About the Author: Caleb Scharf is the director of Columbia University's multidisciplinary Astrobiology Center. He has worked in the fields of observational cosmology, X-ray astronomy, and more recently exoplanetary science. His latest book is 'Gravity's Engines: How Bubble-Blowing Black Holes Rule Galaxies, Stars, and Life in the Cosmos', and he is working on 'The Copernicus Complex' (both from Scientific American / Farrar, Straus and Giroux.) Follow on Twitter @caleb_scharf.
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