Is Water Flowing on Mars?

[Ian David]

More than a century ago, telescopic observers often reported seeing a "wave of darkening" that spread toward the Martian equator from its polar regions during local spring and summer. This changeover, they assumed, resulted from the annual green-up of alien vegetation as the icy polar caps melted, and the notion of a seasonally verdant Red Planet persisted well into the 1960s, until spacecraft images showed us otherwise.

There's water on Mars, to be sure. Billions of years ago torrents of water flooded parts of the surface and gouged huge, nasty-looking flood channels in the landscape. But all that water now lies frozen in thick polar slabs or buried out of sight.

Today Mars is a bitterly cold and dessicated place, at least at ground level. But admit it: aren't you still captivated by the idea that liquid water is flowing somewhere across those ruddy plains? Is it even remotely possible to find a few drops here and there given the current Martian climate?

A decade ago, the high-resolution camera on NASA's Mars Global Surveyor spotted sets of narrow gullies snaking down the walls of some craters. At the time many researchers thought water must be periodically oozing out of cracks in the rock and trickling downslope. It's still not clear how those gullies form, but the minds of most it seems that they're not active now.


These two images, taken in May and August 2009, show the appearance of narrow flows on the northwest-facing slope of Asimov crater on Mars. This view is about 450 feet (120 m) across.
NASA / JPL / Univ. of Arizona

More:
http://www.skyandtelescope.com/community/skyblog/newsblog/117806243.html

[HereSince1628]

1. It's that or Martians are racing dune buggies.

[Warpy]

2. Dust blown by an incredibly thin atmosphere

might be acting much the way water does here on earth to sculpt these channels.

Just being devil's advocate here.