Blue Mars - Kim Stanley Robinson [132]
It was the steepest of the big four volcanoes, but there was no encircling escarpment, as around Olympus Mons; so she could put the rover in low gear and grind on up, as if taking off into space, in slow motion. Lean back in her seat and take a nap. Head on the headrest; relax. Wake up on arrival, up at twenty-seven kilometers above sea level, the same height as all the other three big ones; that was as high as a mountain could get on Mars, basically, it was the isostatic limit, at which point the lithosphere began to sag under the weight of all that rock; all of the big four had maxed out, they could grow no higher. A sign of their size and their great age.
Very old, yes, but at the same time the surface lava of Ascraeus was among the youngest igneous rock on Mars, weathered only slightly by wind and sun. As the lava sheets had cooled they had stiffened in their descent, leaving low curved bulges to ascend or bypass. A distinct trail of rover tracks zigzagged up the slope, avoiding steep sections at the bottoms of these flows, taking advantage of a big loose network of ramps and flowbacks. In any permanent shade, spindrift had settled into banks of dirty hard-packed snow; shadows were now a filmy blackened white, as if she drove through a photographic negative, her spirits plummeting inexplicably as she drove ever higher. Behind her she could see more and more of the conical northern flank of the volcano, and north Tharsis beyond that, all the way to the Echus wall, a low line over a hundred kilometers away. Much of what she could see was patchy with snowdrifts, windslab, firn. Freckled white. The shady sides of volcanic cones often became heavily glaciated.
• • •
There on a rockface, bright emerald moss. Everything was turning green.
• • •
But as she continued to ascend, day after day, up and up beyond all imagining, the snow patches became thinner, less frequent. Eventually she was twenty kilometers above the datum— twenty-one above sea level— nearly seventy thousand feet above the ice!— more than twice as high as Everest was above Earth’s oceans; and still the cone of the volcano rose above her, a full seven thousand meters more!Right up into the darkening sky, right up into space.
Far below scrolled a smooth flat layer of cloud, obscuring Tharsis. As if the white sea were chasing her up the slope. Up at this level there were no clouds, at least on this day; sometimes thunderheads would tower up beside the mountain, other days cirrus clouds could be seen overhead, slashing the sky with a dozen thin sickles. Today the sky above was a clear purple indigo suffused with black, pricked with a few daytime stars at the zenith, Orion standing faint and alone. Out to the east of the volcano’s summit streamed a thin cloud, a peak banner, so faint she could see the dark sky through it. There wasn’t much moisture up here, nor much atmosphere either. There would always be a tenfold difference between the air pressure at sea level and up here on the big volcanoes; pressure up here must therefore be about thirty-five millibars, very little more than what had existed when they had arrived.
Nevertheless she spotted tiny flecks of lichen in hollows on the tops of rocks, in pits that caught some snow and then a lot of sun. They were almost too small to see. Lichen: a symbiotic team of algae and fungus, working together to survive, even in thirty millibars. It was hard to believe what life would endure. So strange.
So strange, in fact, that she suited up and went out to look at them. Up here one had to employ all the old careful habits: secure walker, lock doors; out into the bright glare of low space.
The rocks that harbored the lichen were the kind of flat sunporches on which marmots would have sunbathed, if they could have lived so high. Instead, only little pinheads of yellow green, or battleship gray. Flake lichen, the wrist-pad guide said. Bits of it torn away in storms, blown up here, falling on rocks, sticking like little vegetable limpets. The kind of thing only Hiroko could explain.
Living things.