reply to post by Arken
NASA was reasonably confident that Gale Crater was once a very wet place even BEFORE Curiosity
got there. In fact, Gale Crater was
as the landing site because NASA felt that it possibly was the site of an ancient lake. Also Mt. Sharp is there in the
crater, and geologists feel Mount Sharp may have had a watery past.
Here are the reasons NASA scientists felt confident beforehand that Gale Crater was once very watery, and probably even held a lake:
1. Orbital analysis of the soils indicated clays and sulfates. Clays are known only to form in very wet environments and standing water.
2. Symmetrical cemented sediments. This type of sediment usually forms under water and is laid down by water.
3. Mount Sharp (now known as Aeolis Mons). Orbital analysis of Aeolis Mons shows it to be a mountain built totally from sediment -- maybe even
sediment laid down by deep water (although also possibly laid down by wind or volcanic activity)....
NASA feels it is possible that after Gale Crater was formed it was totally covered by deep water. Over many years, sediment from that water may have
filled Gale Crater to the top and beyond. Under this hypothesis, after Mars lost its water, billions of years of wind erosion blew away much of that
sediment in Gale Crater, exposing the crater, but leaving some of the sediment behind as Aeolis Mons (Mt. Sharp).
Investigating the exposed strata on the sides of Aelois Mons is one of the primary missions of Curiostity
. There are canyons along the sides
of the mountain by which Curiosity
could do a detailed analysis of those sedimentary layers.
So it's not really a surprise that Curiosity
confirmed the existence of clays and ancient water that NASA already believed existed in Gale
Crater -- Gale Crater was CHOSEN for that reason.
By the way, water does not necessarily mean fossils, but NASA isn't closed minded to the idea (although they aren't necessarily "expecting" to find
fossils, either). NASA geologist Matthew Golombek was once asked "In his wildest dreams"
what he hoped Curiosity would find in the strata
layers of Mt. Sharp/Aeolis Mons. He answered that "in his wildest dreams" he hoped to find fossils indicating past life, but he qualified that by
saying that he didn't necessarily expect it...
NASA scientists have lofty dreams, too, and aren't afraid to think big.
edit on 1/22/2013 by Soylent Green Is People because: (no reason given)