The European Space Agency's Mars Express spacecraft has been mapping Mars for twenty years now. In honor of the occasion, the space agency has released a global color mosaic of the red planet that's more than just red. The High Resolution Stereo Camera (HRSC) science team has stitched together 90 images taken from 4000 to 10,000 kilometers above the surface to show the features of Mars in the clearest detail yet.
Mars look pretty much all red in the images we've seen before, because the planet has so much iron oxide. That's what we call rust. But Mars also has more dense, dark bluish-gray sand made of volcanic basalt that formed enormous dunes across the center of the planet from this angle. It also has clay and sulphates that formed from the contact of water with volcanic materials that show up as lighter colors. Read more about the image and how it was made at the German Aerospace Center. -via Kottke
(Image credit: ESA/DLR/FU Berlin (G. Michael))