[extropy-chat] Mappa Mundi

[Anders Sandberg]

http://xxx.lanl.gov/abs/astro-ph/0309415
[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.



-- 
Anders Sandberg
http://www.nada.kth.se/~asa
http://www.aleph.se/andart/

The sum of human knowledge sounds nice. But I want more.