[X] My Assistant

[Guest_paulanderson_*]

Acidic water or volcanoes / impacts? The debate is on! I kind of like this actually, for my birthday today (39 now, getting old)....

Updates regarding this today from Nature, CU and Space.com:

The Waters Ran Shallow
http://www.nature.com/nature/journal/v438/...e051222-10.html

Mars Region Probably Less Watery In Past Than Thought, Says Study
http://www.colorado.edu/news/releases/2005/470.html

New Studies Question Mars Water Assumptions
http://www.space.com/scienceastronomy/051221_mars_dry.html

Regardless though of whether they are correct or not regarding the acidic sulphate deposits in these scenarios, the earlier clays are still another matter...!

The Space.com article includes comments from Squyres (who it says was not contacted prior to the article being published):

"Squyres said a deeper understanding of the situation came when Opportunity examined Endurance Crater, where observations were made of 25 vertical feet of rock outcrops. Those results were published just a month ago, after the two Nature papers had been submitted. Knauth, McCollom and Hynek "hadn't seen that stuff when they wrote their papers," Squyres said. The nature of the layering and grain sizes deeper inside Endurance Crater "is absolutely incompatible with a volcanic or impact origin," Squyres said. It is "completely compatible" with the idea of windblown material, and the upper meter or so "shows evidence for deposition of water. The chemistry varies with depth in a way that requires that subsurface liquid water interacted with the rocks after they were deposited." Squyres emphasized that his team has always thought the water was mostly underground, occasionally creating small surface lakes that evaporated quickly. Squyres also stressed that nobody has done anything other than good science with the data available. "It's always good to have alternative hypotheses," he said. "In the end, the best ideas win. It forces everybody to go back and sharpen their arguments. All of this is a good thing."

[odave]

I've been daydreaming along the same lines, that someday my great-grandchildren might hike the Spirit Interpretive Trail in Gusev Planetary Park. Hopefully they'll be able to keep the tacky tourist shops to a minimum. Though if I'm still alive, I wouldn't mind getting a "My Grandkids went to Gusev and all I got was this lousy T-Shirt" shirt