July 30, 2003
The Earth has carried you around the Sun again, steady as ever, while the stars kept their patient watch.
Frosty Mountains on Mars
Birthday · July 30, 2003
A little universe, just for you
Your date.
Ready to give.
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APOD published July 30, 2003. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.
What causes the unusual white color on some Martian mountains? The answer can be guessed by noticing that the bright areas disappear as springtime takes hold in the south of Mars: dry ice. Dry carbon dioxide ice sublimates directly to gas from its frozen state. The frosty mountains, named Charitum Montes, have been covered with carbon dioxide ice over the Martian winter. The serene scene pictured above is not a photograph, but rather a computationally constructed digital illusion resulting from the fusion of two color images from the Mars Orbital Camera and topographic data from the Mars Orbiter Laser Altimeter. Both instruments operate from the Mars Global Surveyor robot spacecraft currently orbiting Mars. The red planet continues to grow larger in terrestrial skies as Earth and Mars move closer to their recent-record closest approach on August 27.