Terrestrial Planets, Page 17: [Previous Page] [Next Page] [Class Home Page] Textbook pages 191 - 194

Where is the Water on Mars now?

Certainly some of the water is locked up in the Ice Caps, and some is in the atmosphere (very little). However, it appears that significant liquid water may lie just under the surface of Mars.

Mars Global Surveyor (MGS)
Launched in November, 1996, MGS began mapping Mars in April, 1999 at an altitude of 250 miles. Perhaps one of the most significant findings was evidence of water flowing relatively recently. Gullies seen on Martian cliffs and crater walls in a small number of high-resolution images suggest that liquid water has seeped onto the surface in the geologically recent past.

The gully land-forms are found on slopes facing away from sunlight, and at latitudes from 30^o to 70^o. The relationship to sunlight and latitude may indicate that ice plays a role in protecting the liquid water from evaporation until enough pressure builds for it to be released down a slope.




The relative freshness of these features indicate some of them are active today--liquid water may presently exist at depths of less than 500 meters (1640 feet) beneath the Mars surface.

These results from the MGS have two profound implications:

1) If water is this accessible, it makes colonization of Mars more feasible.
2) We should be searching much DEEPER in the Martian ground for life.

Results from the Rovers
The Mars rovers, Spirit and Opportunity, landed in January 2004 on an $835 million mission to search for signs of past water on the planet. They have uncovered tantalizing evidence of a watery past on the Red Planet, though the data are still being sifted.

Could life have ever formed on Mars?
In Earth's history, the important time for the formation of life is between 3.5 and 3.8 b.y.a. Mars may have had very similar conditions at this time. We know rocks can be exchanged from one planet or moon to another. Might bacteria-ridden rocks from Earth, hurled into space from large meteorite impacts, make their way to the Martian surface? It would take millions of years, but maybe some bacteria could survive the trip.