The existence of these organisms suggests the range of life which may have evolved within the Martian surface. Subterranean Environments Bacteria has been found in rocks buried up to two miles underground. There may be more organisms living underground than at the Earth's surface. A rock from the ancient martian crust has revealed tantalizing hints of fossil micro-organisms that may have lived more than three billion years ago. Liquid water, the essential ingredient for life, once flowed on the surface of Mars.
Water probably exists today, below the icy crust of Jupiter's moon, Europa.
The search for life within the solar system will continue on planned spacecraft missions to Mars, Europa, Comet Wild-2, and Titan. Mars Meteorites Scientists have determined that 15 meteorites were originally from Mars. The composition of gases found in some of these rocks is nearly identical to the composition of the gases in the martian atmosphere measured by Viking. Carbonate globules, found in ALH840001, are surrounded by black and white rims. Using a scanning electron microscope, scientists probed deeper into the carbonate globules and discovered features that resemble fossilized bacteria.