Mars clays may have volcanic source
Deposits didn’t need flowing water to form, new research suggests
http://www.sciencenews.org/view/generic/id/344133/title/Mars_clays_may_have_volcanic_source
Quite interesting how a paradigm can be overtaken (of course, this is speculation at this point; I am just talking in general here). It will be interesting to watch how this plays out. Venus is generally well held to be a bone dry planet with a surface temp hot enough to melt lead and very little water in all those clouds. Mars, at least until I read the above article, was pretty much universally considered to be a very wet planet, much like Earth is today, in its very early history. The scientific consensus seemed to be that once Mars’ core cooled and its protective magnetic shielding vanished (something that will eventually happen to Earth, but not for, I think, something like a billion years) that the water was all evaporated and then blown away by the solar wind. Perhaps it did have a magnetic field, but never had the huge oceans.
This doesn’t have to mean that there never was life on Mars (indeed, this doesn’t preclude there still being life on Mars), just that it would have had to make do with a lot less water. I recall watching a show that talked about the remelting of Earth when the moon collision happened (there was also, I believe, a time during the ‘late heavy bombardment’ where the surface might have got molten as well) and they mentioned that molten rock was actually a sponge for water. Rather unintuitive to me, that thousand degree liquid rock would actually be a reservoir for water, but in science things are not always intuitive. Anyway, the idea was that our ocean’s worth of water wouldn’t necessarily be lost during the moon collision, rather the opposite. Then, when the surface cooled the entrained water would be released and the hydrologic cycle would begin again.
