Earlier this year Nasa released pictures from the Mars Global Surveyor which indicated that in recent geological time, water has flowed on the surface of Mars. The features resemble the characteristic appearance of channels cut by water on the earth, and the lack of erosion suggests that flash flooding has taken place on Mars in recent history. There are freshly cut gullies ending with fan shaped accumulations of debris where flood waters deposited sediments, including objects the size of boulders. Most of the gullies are found in the southern hemisphere, and few in the north. The discovery that water still exists below the surface of Mars in a frozen state suggests that it might once have been possible in the distant past for the planet to have supported simple forms of life. Since the origins of single celled life forms remains one of the mysteries of biological science, finding concrete evidence that such organisms developed on Mars in the distant past, while it would not solve the mystery, would at least provide evidence that the processes involved were common, and provide an impetus to further research.
MOC Team, MGS, NASA
Several decades ago the Mariner 9 spacecraft returned evidence of canyons (similar to the grand canyon) that indicated that hundreds of millions of years ago, water once flowed on Mars, and pictures of formations resembling dry river beds on earth have been released. What makes the most recent discoveries unusual is that the pictures are the highest resolution images ever taken of the Martian surface, and they show that the new evidence for water channeling is a recent occurence. Due to the extremely low atmospheric pressure on Mars, it is not possible for water to exist in a fluid state on the surface. Scientist suggest that the water either exists in a frozen state near the surface, or that water exists underground in liquid aquifers. While scientists have constructed a model which mimics the behavior of the water on the Martian surface, and describes the physics of the flooding, he process at work which causes the flash flooding to start in the first place is not presently understood. If liquid water does exist below the surface then it is possible that some type of simple life forms might be able to survive on the planet, much as life does in such inhospitable enviroments as the freezing waters underneath the polar ice caps, or in the near boiling water near deep ocean volcanic vents.
NASA/JPL/Malin Space Science Systems
In a related story, the Mars Global surveyer has taken photographs of rock outcroppings and found similar evidence for accumulated layers of sedimentation on Mars that would be found on earth by observing such formations as the Grand Canyon. These layers of sedimentation indicate, once again, the presence of water on the planet in the long distant past, and since on earth, fossils are always found in regions where conditions favored the gradual accumulation of sediments to form sedimentary rock, the possibility of fossil beds existing on Mars in these deposits, as they do on earth, has been mentioned. The combination of evidence for the existence of water on Mars, at the present, and the existence of surface liquid water on Mars in the distant past, combined with the intriguing possibilities suggested by the existence of sedimentary rock indicates some interesting possibilities.
