Mars Dry Most of Its Life

If Mars had liquid water, it was only briefly early in its history.  Observations from the Mars Express, which just celebrated its first year in orbit, show no hint that liquid water has existed any time recently, reports Nature Science Update.  It’s not that H2O is rare; it is abundant at the poles, for instance, but is locked in solid ice.  Apparently there was never much of a greenhouse to liquefy the water for long, despite the evidence of water-altered layers found by the Mars Exploration Rovers (see 12/03/2004 entry).
    Because many scientists had envisioned a warmer, wetter Mars that could have supported life until recently, the new findings were bad news.  Said one UK researcher, “In a sense, we’ve been barking up the wrong tree for 20 years.”  That leaves them with a sore throat but no coon.
    Early papers were released for Science¹ this week.  In the Feb. 17 issue,² Richard Kerr said that now the younger, dryer side of Mars is coming out.  The OMEGA spectrometer on Mars Express has detected no carbonates or clays, which should have been plentiful on a wet Mars.  Instead, it has found an abundance of minerals like olivine that show no water alteration or weathering.  “Sulfuric acid from volcanic eruptions apparently combined with water to corrode martian rock and produce sulfates around the planet,” Kerr pointed out – hardly a scenario for a thriving beachfront community of living organisms.  “All in all,” he concluded, “Mars since ancient times is looking awfully cold and dry.”
    That’s not stopping some from putting a positive spin on the findings, and continuing to claim life might still be found there: see Space.com stories from Feb. 16 and Feb. 17.

¹See six papers published online Feb. 17 on Science Express.
²Richard Kerr, “And Now, the Younger, Dry Side of Mars Is Coming Out,” Science, Vol 307, Issue 5712, 1025-1026 , 18 February 2005, [DOI: 10.1126/science.307.5712.1025a].

Venus was supposed to be a tropical Jurassic paradise of swamps and dinosaurs, but now it is known as a lead-raining hell (see 11/26/2003 entry).  Mars was once envisioned as the home of intelligent beings who engineered advanced water projects.  Then it was demoted to a land of beachfront bacteria.  Now, it looks like an freezing-cold, desiccated, acidic, toxic waste dump (see 12/03/2004 entry).  Mission planners had better think of a new sales pitch to get the public interested in further exploration.  How about a non-evolutionary angle?  It would sure be a cool place to study catastrophism.  And it sure provides a nice foil to our own world, so that we appreciate and care more for our privileged planet.