Andart

Mappa Mundi

[astro-ph/0310571] A Map of the Universe by J. Richard Gott III, Mario Juric, David Schlegel, Fiona Hoyle, Michael Vogeley, Max Tegmark, Neta Bahcall and Jon Brinkmann. Extra material at http://www.astro.princeton.edu/~mjuric/universe/.

A map showing a geocentric perspective of the entire universe. The trick is to make one direction logarithmic, which makes it possible to depict everything (more or less) from the Earth's core out to the Big Bang. The other direction represents declination, making this a slice across the universe along the ecliptic.

If I have inherited anything from my father, it is his love of maps. A good map gives a sense of a place and its context. It should have as much information as possible but still "quiet" information: information that doesn't distract the viewer when viewing the map in general but directly available once you look for it. And the more complete the map is, the better.

By these standards this map is very good. It gives a sense of the stuff we find around us. The authenticity created by plotting the positions of satellites, minor bodies and planets at a particular moment in time is reassuring and reveals many interesting patters (for example, look at the asteroid belt and how they are affected by Jupiter). I wonder what Edward Tufte would say about it?

I would probably have rendered it a bit different by applying textures to represent the galactic disc etc as coloured stars (perhaps grey) to make it less abstract. It is also a bit sad that the names of many neighbouring galaxies are not written in full, for popular science purposes it is better to call M31 "The Andromeda Galaxy (M31)" than just M31.

In the paper the authors discuss the intricacies of the mapping. Beside the usual issues of conformality (keeping angles locally identical to avoid distortion of shape) they have to deal with the relativistic effects of a curved space-time. It is a nice loop: geometry in curved space was developed by mapmakers, turned by Gauss (who did geodesic measurements) and others into a mathematical discipline that were to be the seed and engine of general relativity and now returns home to itself to make a map.

I wonder if one could make a good 3D box map by plotting Ascension too? Obviously there are tricky issues of conformality, but it would probably be worthwhile to show how the different planes align (or rather not align).

The authors also suggest plenty of interesting applications and ways of presenting the map, from wallscreens and lasershows on buildings to rugs for astronomy labs. A scientific visualization this good is bound to crop up in many places.

Posted by Anders at January 13, 2004 01:05 PM