In short, Mars went from -- at some point
in the past -- having a high pressure?, warm?, wet? climate
to having its current conditions.
Bruce Jakosky, a pretty smart guy
who knows a bunch about climate and
who is not a part of the Mars rover
team, was quoted in a
CNN salty sea article
as saying that the rocks
"are known to be from Mars' early epochs, so the water was likely there in the very, very distant history of the planet's roughly 4.5 billion years of existence." No evidence is offered for this
age, though -- how do they know this?
I'm stumped.
Last questions: Where did the water come from,
and where did it go?