This could be very cool.
Striking images taken by NASA’s Mars Global Surveyor spacecraft suggest the presence of liquid water on the Martian surface, a tantalizing find for scientists wondering if the Red Planet might harbor life.
The orbiting U.S. spacecraft enabled scientists to detect changes in the walls of two craters in the southern hemisphere of Mars apparently caused by the downhill flow of water in the past few years, a team of scientists announced on Wednesday.
The idea of flowing water on our nearest planetary neighbor is pretty exciting, but bear in mind a few caveats. Most important, the Mars Global Surveyor never phorographed water. Rather the satellite photographed a crater wall before and after something that might be water (“five to ten swimming pools”) dug a fresh gully in it. As much as anything my skepticism comes from the fact that Mars doesn’t have internal geologic heat like the Earth. A substaintially smaller planet, Mars’s molten core froze up and stopped spinning millions of years ago. On Earth liquid water can only sink so deep into the crust before natural heat transforms it to gas and it comes shooting back to the surface (e.g., Old Faithful and deep-ocean thermal vents). The inability to remain liquid beyond a certain depth keeps water shallow. On Mars, a colder planet, the water flash point ought to be quite a bit further down. Background radioactivity and pressure will prevent the planet from cooling all the way to the core, but the point where water turns into steam has probably retreated deep enough to keep liquid water well out of our reach.
This news means one of two things. Maybe a dust landslide can create an erosion track similar to what water does on Earth. Let’s call that the more likely possibility since it agrees with everything that we know about the Red Planet. But still, the possibility of liquid water near the surface almost inevitably means life. Primitive bacteria color the waters in Yellowstone Park’s hottest, most acidic thermal pools, they live in the interstitial water in tiny rock crevices miles beneath the Earth’s surface, they live in the superheated anoxic water surrounding deep-sea thermal vents. If water flows on Mars then odds are better than one in two (my math. YMMV) that something has found a way to persist. So, for a change, I really won’t mind being wrong about this.
POSTSCRIPT: Speaking of space science – in the past month NASA lost touch with the Mars Global Surveyor spacecraft. You would think that the space program would be on fire to repeat programs that work and have a direct impact on us – intense robotic surveying of the Red Planet and deep scrutiny of the Earth’s changing climate. Nope. NASA administrators have been instructed to steer their attention and resources towards…a moon base.
Let me clarify. America won’t build a moon base. Moving a few modules into low Earth orbit (the International Space Station) took almost more resources than several space agencies could spare. Escaping Earth orbit entirely demands an investment several orders of magnitude more intense. It is tempting to think that every aspect of technology has revolutionized as rapidly as microprocessors* but in the case of rocket science, it really hasn’t. Pushing mass beyond the reach of Earth’s orbit takes just as much energy as it did in 1965, and it isn’t trivial. Shuttling monthly supplies (food, water, oxygen, fuel) would take more resources than our space agency currently spends on its entire budget. The technology isn’t close and the budget question is laughable (maybe we can ask China to extend our credit? snrk). The only good that a moon mission will do is transfer NASA resources away from projects which could prove politically damaging for Republicans and into a useless black hole. Call it robbing Peter to pay James Inhofe.
(*) To illustrate, my wife returned a 4-GB iPod last month for warranty reasons. Circuit City handed us an equal value unit – 8 GB of memory in a substantially better package. We had owned the earlier model for less than ten months. Moore’s Law in action.