Yes, there is now good evidence from satellite observation systems to show that Mars has water ice locked up in polar ice caps. Some scientists feel that the ice deposits have mass equivalent to a global water layer approximately 11 meters thick. There is also evidence that Mars may have had streams or other water sources at one time. Mars ground exploration may be the only way to determine if water is still available beneath the surface at non polar locations. In one reported image, a shining snake of light flows from a hidden spring into a crater's depression, an orbiting camera aboard NASA's Mars Global Surveyor catching sunlight reflected by the evaporating liquid. In another, a smear of ice grows mysteriously over a period of years, expanding like a slow-motion inkblot over the red planet's parched landscape.
"If this was coming down the slope [toward you], you'd want to get out of the way," said NASA's Kenneth Edgett, a scientist with Malin Space Science Systems. "This is the squirting gun for water on Mars"
"We've found it," said Michael Meyer, NASA's lead scientist on their Mars Exploration Program. "Water seems to have flowed on the surface of today's Mars." Philip Christensen, a professor from Arizona State University in Tempe, added that the discovery would change NASA's plans for Mars exploration, not to mention our understanding of the desert world itself.
Mars Global Surveyor has captured the images while tracking changes in geography over a period of years. Dry gulleys, previously through to have held water no more recently than millions of years ago, were found to have filled between observations. Certain tasks remain, according to the panelists. For example, a spectrographic analysis of the "white stuff," to prove that it is definitely water. These might be carried out by the Mars Reconnaissance orbiter, recently arrived in order to replace the aging Global Surveyor. "These things appearing bright is extremely unusual," said to NASA panelist Michael Malin, explaining why NASA believes the apparitions are water, not mere avalanches of dust. "In the past, the things we've seen are very dark ... this requires some kind of fluidizing agent."
Subsurface aquifers or melting ground ice were floated as possible sources of the water. One of the springs even appears at a fault line, according to Malin, just as they often do on Earth. The shortness of the gulleys, which seem to flow for but a few hundred yards, might be accounted for by a process similar to a volcano's eruption on Earth, with water instead of magma building up underground, and ice, instead of fire, characterizing the resulting flow. Finding water on Mars is only the tip of the iceberg, literally, as we further explore its surface.