NASA’s Big Mars Story

Every time NASA ballyhoos a press conference to announce an exciting discovery about Mars, the public bets heavily that the news will either be about water (What, again?) or life (Finally!)

This week’s communique is about both, and neither. But there’s no gainsaying the fact that it’s exciting.

It concerns the seasonally changing features on crater walls and other vertical topography, known as recurrent slope lineae. These things look like long, dark fingers running downhill, and they become prominent when summertime Mars warms up to temperatures that, while cold for Earth, are considered balmy on the Red Planet.

The lineae resemble seepage – melt water just below the dry, Martian surface that’s oozing its way downhill. Now, researchers using spectral analysis from an orbiter have determined that it most likely is water – not any of the other possible phenomena. That’s a strong indicator that there are subsurface reservoirs at very shallow depth on Mars. In other words, Mars apparently has lakes today; they’re just covered by a rusty, dusty carapace of boring dirt.

Now many astrobiologists think that the Red Planet was once a kinder, gentler world. Three or four billion years ago or thereabouts, Mars may have had occasional rivers, lakes and even oceans on its surface. The canyons and lakebeds are all dry as dandruff today, but given the ubiquity of the lineae, subsurface aquifers could still be present in abundance.

And so the scenario is as obvious as it is compelling: In its youth, Mars may have actually spawned single-celled life. As conditions slowly deteriorated, this life adapted to whatever environments were still around – including within the pitch-dark, subsurface aquifers. It could still be enjoying a cryptic lifestyle today.

Knowing this, how might we find these microscopic Martians? NASA tried looking for life on —> Read More