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A Third of Mars Could Have Been Underwater
Matt_dk writes "An international team of scientists who analyzed data from the Gamma Ray Spectrometer onboard NASA's Mars Odyssey reports new evidence for the controversial idea that oceans once covered about a third of ancient Mars.
'We compared Gamma Ray Spectrometer data on potassium, thorium and iron above and below a shoreline believed to mark an ancient ocean that covered a third of Mars' surface, and an inner shoreline believed to mark a younger, smaller ocean.'"
It's gonna be a pain in the ass to get one of those rovers up to 88 miles per hour.
Makes some sense to see potassium anomalies in the old basins if there was water there which has since been evaporated, with the concentration increasing toward the centres, as potassium salts are somewhat more soluble than their sodium equivalents, theyd be the last left to precipitate out. Thorium on the other hand is usually residual, at least here on Earth, and tends to concentrate along shorelines and riverbeds due its high density and low solubility.
Watashi wa chikyubutsurigakusha desu.
Eh, whatever. Mostly it was about using the word antediluvian.
Haven't we gotten past the point where the idea of Mars once having lots of water is controversial? I mean, it seems as if every new piece of evidence points in that direction, so what exactly still makes it controversial?
You mean interesting as in "Hmmm, we might want to have some means of space exploration in the next century at the latest"
A century is a very short amount of time on the solar timeline. The Earth won't fall into the Sun for 5 billion years or so, and even then, the Sun will have lost enough mass that models predict the Earth may be flung off into deep space rather than falling into the Sun.
The more immediate concern is that over the next 1 billion years, the luminosity of the Sun will increase about 10% or so, which should be fairly devastating to life on Earth. But, thats due to the Sun getting older, not the Earth getting closer.
The question is why Mars would have oceans then and not now. Put water on the surface today and that which doesn't freeze will evaporate due to the low atmospheric pressure. The atmospheric pressure is low because Mars doesn't have that strong a gravitational field to sustain an atmosphere. So the question becomes, how did Mars ever manage to have an ocean in the first place? It's not likely that it was more massive earlier on so it's not likely to have ever had an earth-like atmosphere that recycles the water back to the oceans. Sans gravity, you don't get a steady-state atmosphere. Sans atmosphere, you don't get to keep your water. Bottom line - it's a problem full of paradoxes. Weird.