Martian Mysteries

As noted in an earlier post, I find newspaper reports of scientific discoveries irritating and baffling. Their writers must be either scientifically illiterate themselves, or forced to dumb down their writing so much that they can’t convey adequately exactly what has been discovered, and how.

For example? Ok. Consider this. News stories have appeared this week announcing new proof that Mars was at one time much wetter than it is now.

NASA scientists deduce the existence of such water from an accidental discovery. While moseying across the Martian landscape, the Mars rover Spirit dragged a broken wheel, like those on supermarket grocery carts, gouging out patches of bright soil (see photo). Spirit's instruments were sternly directed to perform their intended functions, i.e., to test these patches chemically and by spectrometer. They did so, and in due course found that the bright soil consisted of a surprisingly high 90 percent silica (SiO2). The silica was found to be non-crystalline, which means that it’s not quartz, the primary form in which silica appears in soils (or sand) on Earth.

Now, I have no background in geology. But when a newspaper writer tells us that we now have proof that water used to flow on Mars, because Spirit kicked up some white soil with a high silica content, I don't think he should expect us to just look at him with big sheep eyes, nodding our woolly heads. I really would like to understand how the NASA scientists reasoned from point A to point B.

Silica is a metallic oxide. It's a component of both igneous and metamorphic rocks, minerals formed by high heat and/or pressure. No water is required to produce silica. At least, so far as I know. For example, no one claims that water ever flowed on our own Moon. But lunar shield volcanoes are composed of silica-rich lava. (Otherwise, as I understand it, the lava wouldn't have had much starch and would've flattened out into basalt maria, as indeed can be seen to have happened on much of the lunar surface.) Likewise, the powdery surface soil ("regolith") in the lunar highlands is rich in both aluminum and silica. No one seems excited about the silica content in these areas on the Moon. What’s the difference between them and the patches newly discovered on Mars? Is it that there's a higher concentration of silica on Mars? Ninety percent, as opposed to, say, 60 or 70 percent? And if so, what does this have to do with water?

All the journalist could add for our edification was that the silica could have been formed by acid vapors interacting with water, or maybe by hot springs. Huh? Couldn’t we have been given at least a primitive discussion of the chemistry that would cause these vaguely described conditions to result in unusually silica-rich soil?

"You could hear people gasp in astonishment," said Steve Squyres, principal investigator for NASA's twin Spirit and Opportunity rovers at Cornell University in Ithaca, N.Y. "This is a remarkable discovery."

No doubt. But the news report should have provided us enough geological and chemical background to help us share in NASA’s astonishment.

I'm still not sure why 90 percent silica content proves the existence of water, even after a little snuffling around through interplanetary geological websites. Any geology buffs out there who’d like to weigh in with some expert insight?

Where No Man Has Gone Before

Fellow blogmeister Zach and I expressed our longing in these pages recently for a larger, less well-mapped world to explore (see comments to The Fading Light of Shangri La). Well, I'll be darned if astronomers haven't obligingly come up with the discovery of Gliese 581 C.

Gliese 581 C, for those of you who have spent the past week in a scientific vacuum, is being trumpeted as the most Earth-esque planet, the most humanly-desirable extraterrestial real estate, ever discovered in the Universe. It is one of three planets now known to revolve around the red dwarf star, Gliese 581. Note that none of these planets has ever been seen by the eye of man. Or woman. They've been inferred to exist only from minute wobbles noted in the movements of the star they circle.

And yet. And yet, our cunning astronomers can tell us a lot about this new (new to us, at least) planet.

What excites them most is that the planet's mass suggests that it must be either solid or liquid, or a combination of the two -- not gaseous like such giants as Jupiter and Saturn. They have calculated, moreover -- all from slight perturbations in the red dwarf star's motions, mind you -- that the mean surface temperature must fall between 32 degrees and 104 degrees F. (Which makes it more livable than, say, Chicago.) At those temperatures, any lake you might fall into would be filled with H2O, not some ghastly liquid like methane. A very nice feature, indeed, if you happen to be a carbon-based human, as so many of us are.

In the maddeningly imprecise language that newspapers use when discussing science, MSNBC announces that the newly discovered planet is "50 percent bigger than earth." Does that mean 50 percent larger diameter, or 50 percent more surface area? Probably the former, which means that the surface area would actually be 2 1/4 times that of the earth. (The math is left as an exercise for the reader.)

Which makes it a nice big world to live on and hike around. Lots of blank spaces on Gliesian maps still to be explored and to lose oneself in.

One slight drawback for some might be that gravity at the surface would be about 50 percent greater than on earth. If you are a trim, athletic 150 lb. here on Earth, in other words, you would find yourself waddling around as a somewhat portly 225 pounder on Gliese 581 C's more spacious surface.

Another peculiarity is that the red dwarf star is so cool (literally, I mean) that its planet's surface remains comfy even though its orbit is very close to its "sun." So close, in fact, that Gliese 581 C zips around its short orbit every 13 days. Not only might that get old awfully fast -- so would you! While your friends back on Earth aged a year, you would have experienced 28 Gliesian years!

Look at the bright side: if their winters are like Seattle winters, they would seem more tolerable if each lasted only 3 or 4 days.

So, I say, all in all, it sounds great. Good climate, water to swim in and drink, quickly changing seasons -- and lots more land to explore. All that's worth putting on a few more pounds.

So how soon do we get there? Hmm. Well, Gliese 581 C does seem to be about 20 light years away, as the crow flies.

"Warp speed, Mr. Sulu!"