Friday, November 20, 2009

The Weather on Mars

Dust Devil Trails on Mars
Hat tip to Anita for reminding me about this striking image, via Astronomy Picture of the Day, from the Mars Reconnaissance Orbiter. The swirly patterns are formed by dust devils that blow aside reddish surface dust to reveal dark material just beneath it.

I am old enough to be reminded of the Nazca lines, geoglyphs made by ancient peoples in a South American desert, that figured prominently in 'ancient astronauts' crankery. The patterns are entirely different, but you can imagine a playful intelligence at work here. 'Dust devil' is an apt term - think of the Tasmanian Devil in old Warner Bros. cartoons. Dust devils on Mars can reach 8 km in height, and have extended the life of Mars rovers by blowing the dust off their solar panels.

Once again Mars evokes an offworldly American Southwest. The Bat Durston theme is quintessentially SF, perhaps the very heart of 'Murrican SF, but oddly enough it never entirely applied to the old, rocketpunk era Mars. The old Mars, Percival Lowell's Mars, was a desert world indeed, but a desert of vast flat plains (the better for the canal system).

No one dreamed that Mars had both the highest mountain and the largest canyon in the Solar System. By pleasing irony, Lowell's observatory is not so far from the Grand Canyon.

Lowell's Mars was flat because it was a slowly dying world, its topography long since worn down by its desert winds. Real Mars fall from Earthlike grace more quickly, its atmosphere now too thin for its winds to wear down Olympus Mons. The forces that break mountains have faded along with the forces that make them. Now the winds of Mars produce only dust devils. (And the occasional planetwide dust storm.)

Yet the dust devils are also a reminded that Mars is not quite dead. Winds swirl across its surface; from time to time liquid water still flows there. It is still a world with weather.

Related Post: I noted in March that in spite of appearances, Mars is fiercely unlike Arizona.


Anonymous said...

Mars' weather reminds me of that line from 'Monty Python and the Holy Grail', "...I'm not dead, yet!" Maybe it'll come back fully to life one day...


Rick said...

Wonderful scene! And yes, that is sort of what I was groping toward. Mars seems sort of freeze-dried and preserved, not quite dead.

Anita said...

Considering where life thrives on this planet, it's a mistake to write off Mars. Most likely it isn't dead, just different.

Carla said...

I caught a snippet of a TV programme the other day describing bacteria that have been in suspended animation deep in the ice of Antarctica for some incredible time. I didn't catch the details but I think it was well over a million years. Maybe also on Mars?

Anita said...

There's the bacteria found 2 miles underground (abandoned mines) feeding on the minerals in the rocks. The creatures that live off the minerals from the volcanic vents in the Pacific. The algae in the near boiling sulfa ponds in Yellowstone. The African shimp that live in water so salty an egg will float in it, also near boiling.

Tough stuff, life.

Rick said...

Speaking of hostile environments, how about the toxic, corrosive rocket propellant that we breathe? Oxygen is a fire looking for a spark, and if it doesn't find one, rusting is just burning in slo mo.

That is what makes life support so challenging. Space is not the problem. The problem is keeping the poisonous brew inside the petri dish precisely balanced, so that it keeps on brewing.

Anita said...

The millions of life forms living in our bodies, among other things processing our food, to whom oxygen is a poison, kill them instantly.

The most significant adaptation of our ancestors wasn't dwelling on land; it was adapting to an oxygen rich atmosphere.