Last year we watched intently as NASA’s Mars Polar Lander dug a small trench near the Red Planet's north pole to expose subsurface water ice. Over days the snow-white patch sublimated in the sunlight, demonstrating that is was indeed ice! We were mesmerized by at last looking at ice on another terrestrial planet.
It never dawned on me that nature had likely already done the heavy lifting – er heavy excavating in uncovering water. Today NASA released pictures of several fresh craters with icy-looking floors. Apparently meteorites have excavated surface material to expose the ice. It then sublimates away over weeks as revealed in time sequence photos. The Mars Reconnaissance Orbiter’s (MRO) spectrometers clinched the deal by taking spectroscopy of the ice and finding water’s signature.
The small craters photographed by the MRO's eagle eyes are only big enough to drop a minivan into. What’s intriguing is that the craters are at the drier mid latitudes, rather than the poles where near-surface ice is more likely. This suggests that NASA's Viking Lander 2, which touched down on Mars in 1976, might have struck ice if it had dug merely four inches deeper, about the size of a pack of cigarettes.
Such a discovery in 1976 might have greatly accelerated NASA's and the public’s interest in going back to Mars for further surface exploration and astrobiology experiments. Instead, there was a two-decade hiatus between Viking and the landing of the Mars Pathfinder and its skateboard-sized rover in 1996. Imagine, a difference of four inches may have accelerated our planetary program by 20 years.
This is especially timely in light of the other big news this week that three different space probes now orbiting the moon have found the chemical signature of water all over the moon's surface. But don’t plan to scoop it into a glass. The ice is so thinly dispersed it is molecules thick, and transient with the moon's day/night cycle. But you could build a snow Martian on the Red Planet.
Tags: Mars
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