Like talk show hosts, NASA's Mars rovers broadcast their findings at television frequencies. They record their observations and send them to the Mars Odyssey orbiter once or twice a day. Odyssey then broadcasts the program -- spectacular images and all -- back to Earth.
Just as migrating birds herald the changing seasons on Earth, sand dunes show seasonal change on the fourth rock from the Sun. From a distance, crescent-shaped dunes near the north pole of Mars can even resemble birds in flight.
If you smacked a frozen chocolate bar on a table, it would break into bite-size pieces resembling the terrain in this Martian crater. To a planetary scientist, this pattern is a tantalizing clue that the ground once contained water ice. When the frozen terrain cracked, in some places the ice melted into flows chock full of sediment. Perhaps the ground is still filled with layers of near-surface ice.
NASA's Mars Odyssey orbiter has found evidence of salt deposits. These deposits point to places where water once was abundant and where evidence might exist of possible Martian life from the Red Planet's past.