Early Life on Earth

Extraterrestrial Life

External Links:

Mars Exploration
NASA's plans for exploring Mars.

Mars Pathfinder
Landed on Mars in 1997.

Mars Global Surveyor
Currently in orbit around Mars.

Mars Express
European Mars mission planned for 2003.

Beagle 2
Planned British Mars lander for Mars Express.

Mars Images
(JPL Welcome to the Planets)

The Whole Mars Catalog

Mars Landing Site Catalog

Three to four billion years ago it is thought that conditions on Mars may have been very similar to those on Earth. There is evidence that Mars at that time had ample liquid water, perhaps even an ocean. Thus it is entirely plausible that Mars may have had abundant life early in its history which might be preserved as fossils.
Since Australia has some of the best fossil remains of early life on Earth, it is not surprising that Australian experts such as Malcolm Walter of Macquarie University are helping NASA to devise the strategy for searching for fossil life on Mars, and to select landing sites for future Mars landers.

Walter advocates targeting spring deposits as the best sites for finding fossils. He points out that hot springs are sites of abundant microbial life and good locations for fossil preservation. He also notes that hydrothermal systems are sites of formation of valuable ore deposits (such as gold, silver, copper, lead and zinc) on Earth. Thus these sites can be found by techniques well known to exploration geologists.

Such ideas are used by NASA to compile their Mars Landing Site Catalog, a catalog containing details of 200 sites of potential interest including about 50 which might contain evidence of former life.