Thursday, August 4, 2011

Into the Briny Blue -- On Mars

There may not be canals on Mars, but it appears there is free-flowing salty water on the planet’s surface after all. Or just underneath the surface. Or not.

It’s kinda hard to tell, because in typical NASA-ese, the announcement hedges every bet:
The images show flows lengthen and darken on rocky equator-facing slopes from late spring to early fall. The seasonality, latitude distribution and brightness changes suggest a volatile material is involved, but there is no direct detection of one. The settings are too warm for carbon-dioxide frost and, at some sites, too cold for pure water. This suggests the action of brines, which have lower freezing points. Salt deposits over much of Mars indicate brines were abundant in Mars' past. These recent observations suggest brines still may form near the surface today in limited times and places.

When researchers checked flow-marked slopes with the orbiter's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), no sign of water appeared. The features may quickly dry on the surface or could be shallow subsurface flows.

"The flows are not dark because of being wet," McEwen said. "They are dark for some other reason."

A flow initiated by briny water could rearrange grains or change surface roughness in a way that darkens the appearance. How the features brighten again when temperatures drop is harder to explain.
Water in the form of ice is known to exist on Mars already (as well as on the Moon), but to see free-flowing water, briny or not, on the surface or just below it, is pretty exciting stuff. There may indeed be physical forces other than wind shifting the surface of the planet and offering yet another spot where future expeditions could search for microbial life forms.

No word if NASA has named the newly-discovered features. Too bad. Giovanni Schiaprelli, the Italian astronomer noted for naming the features he could identify on the Martian surface as “canali” would have loved to help. He named dozens of canals on Mars.

And maybe one of these two guys would want to help as well.

All that matters is you see your world and I see mine. Is that not enough no matter what we each believe?

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