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NASA Finds Evidence of Recent Flowing Water on Mars
SonicSpike writes to mention that Scientists are claiming that they have evidence of water flowing on Mars within the last five years. From the article: "Subsurface aquifers or melting ground ice were floated as possible sources of the water. One of the springs even appears at a fault line, according to Malin, just as they often do on Earth. The shortness of the gulleys, which seem to flow for but a few hundred yards, might be accounted for by a process similar to a volcano's eruption on Earth, with water instead of magma building up underground, and ice, instead of fire, characterizing the resulting flow."
For water to flow, it has to have gotten to the source of the flow first. So, there has to be a mechanism for transport back to the source of the flow. Like rain moves water on Earth back to higher ground. The article offers no speculation on this transport mechanism. I would, of course, suspect evaporation and then dew/frost. But, that would be picked up easily from our probes and even from Earth-based observation.
What am I missing here?
"If you want to improve, be content to be thought foolish and stupid." - Epictetus
For what it's worth, I should point out that this is perfectly consistent with the story that's been gradually developing over the years. We know that there are substantial amounts of hydrogen in the first few meters of most of the Martian crust (cf. the MO Gamma-ray spectrometer) and hence there is likely water ice there. We know that in the distance past large quantities of liquid water flowed on the surface to carve the fluvial geomorphological features we see (cf. MGS MOC images). We know that liquid water sloshed in at least some areas to form certain minerals (cf. MER results). We've seen gullies on the sides of craters that looked recent (cf. MGS MOC images). And now this study which shows gullies being created over the timeframe of a few Earth years. Basically, this is just one more little increment in our understanding of the distribution of water on Mars. This is how science usually works but sometimes press releases unduly hype things.