Monday, April 6, 2009
Out of this world
Amongst my obsessions are globes - but not just of our home planet, but of extra-terrestrial bodies as well. The photo shows my globe (of the earth, with the transits of many great explorers - sadly limited to the Western sort... but better than nothing), my moon-globe and my celestial sphere. The heavenly-named celestial sphere, is a globe with the constellations 'pinned' to the 2D surface of the sphere - as if there really were geocentric Ptolemaic spheres. I would love to have globes of the other planets and satellites (the natural moon-like sort, not the human-made type) in our solar system. The Map Room has a post about what is currently available: the moon from Replogle, Mars and Venus from Sky and Telescope. The globes for our nearest neighbour planets, as well as the moon, and three of the Jovian satellites (moons of Jupiter - once known as the Medician stars, because Galileo knew how to court a sponsor): Callisto, Ganymede and Europa, are based on satellite photography or topography data, of course. The gores (pieces from which a globe is made, since there is no made to map a 2D rectangle onto a sphere) are available, free from the USGS Astrogeology Research Program (also here, here and here). For Mars, they offer photographic or topological gores, as well as instructions on how to make your own tennis-ball or 6.6 inch size Mars globes! I know what paper engineering project I am tackling next!