Overlooking the caldera. She got out of the car, her thoughts flicking about like skuas.
Ascraeus’s nested caldera complex consisted of eight overlapping craters, the newer ones collapsing down across the circumferences of the older ones. The largest and youngest caldera lay out near the center of the complex, and the older higher-floored calderas embayed its circumference like the petals of a flower design. Each caldera floor was at a slightly different elevation, and marked by a pattern of circular fractures. Walking along the rim changed perspective so that distances shifted, and the floors’ heights seemed to change, as if they were floating in a dream. Taken all in all, a beautiful thing to witness. And eighty kilometers across.
Like a lesson in volcano throat mechanics. Eruptions down on the outer flanks of the volcano had emptied the magma from the active throat of the caldera, and so the caldera floor had slumped; thus all the circular shapes, as the active throat moved around over the eons. Arcing cliffs: few places on Mars exhibited such vertical slopes, they were almost true verticals. Basalt ring worlds. It should have been a climbers’ mecca, but as far as she knew it was not. Someday they would come.
The complexity of Ascraeus was so unlike the single great hole of Pavonis. Why had Pavonis’s caldera collapsed in the same circumference every time? Could its last drop have erased and leveled all the other rings? Had its magma chamber been smaller, or vented to the sides less? Had Ascraeus’s throat wandered more? She picked up loose rocks on the rim’s edge, stared at them. Lava bombs, late meteor ejecta, ventifacts in the ceaseless winds. . . . These were all questions that could still be studied. Nothing they did would ever disturb the vulcanology up here, not enough to impede the study. Indeed the Journal of Areological Studies published many articles on these topics, as she had seen and still occasionally saw. It was as Michel had said to her; the high places would look like this forever. Climbing the great slopes would be like travel into the prehuman past, into pure areology, into the areophany itself perhaps, with Hiroko or not. With the lichen or not. People had talked of securing a dome or a tent over these calderas, to keep them completely sterile; but that would only make them zoos, wilderness parks, garden spaces with their walls and their roofs. Empty greenhouses. No. She straightened up, looked out over the vast round landscape, held up and offering itself to space. To the chasmoendolithic life that might be struggling up here, she waved a hand. Live, thing. She said the word and it sounded odd: “Live.”
Mars forever, stony in the sunlight. But then she glimpsed the white bear in the corner of her eye, slipping behind a jagged rim boulder. She jumped; nothing there. She returned to the rover, feeling that she needed its protection. She climbed inside; but then all afternoon on the screen of the rover’s AI, the vague spectacled eyes seemed to be looking out at her, about to call any second. A kind bear of a man, though he would eat her if he could catch her. If he could catch her— but then none of them could catch her, she could hide in these high rock fastnesses forever— free she was and free she would be, to be or not to be if she chose that, for as long as this rock held. But there again, right at the lock door, that white flash in the corner of her eye. Ah so hard.
Part Seven
Making Things Work
An ice-choked sea now covered much of the north. Vastitas Borealis had lain a kilometer or two below the datum, in some places three; now with sea level stabilizing at the minus-one contour, most of it was underwater. If an ocean of similar shape had existed on Earth, it would have been a bigger Arctic Ocean, covering most of Russia, Canada, Alaska, Greenland, and Scandinavia, and then making two deeper incursions farther south, narrow seas that extended all the way to the equator; on Earth these would have made for a narrow North Atlantic, and a North Pacific occupied in its center by a big squarish island.This Oceanus Borealis was dotted by several large icy islands, and a long low peninsula that broke its circumnavigation of the globe, connecting the mainland north of Syrtis with the tail of a polar island. The north pole was actually on the ice of Olympia Gulf, some kilometers offshore from this polar island.
And that was it. On Mars there would be no equivalent of the South Pacific or the South Atlantic, or the Indian Ocean, or the Antarctic Ocean. In its south there was only desert, except for the Hellas Sea, a circular body of water about the size of the Caribbean. So while ocean covered seventy percent of the Earth, it covered about twenty-five percent of Mars.
In the year 2130, most of Oceanus Borealis was covered by ice. There were large pods of liquid water under the surface, however, and in the summer, melt lakes scattered on top of the surface; there were also many polynyaps, leads and cracks. Because most of the water had been pumped or otherwise driven out of the permafrost, it had deep groundwater’s purity, meaning it was nearly distilled: the Borealis was a freshwater ocean. It was expected to become salty fairly soon, however, as rivers ran through the very salty regolith and carried their loads into the sea, then evaporated, precipitated, and repeated the process— moving salts from the regolith into the water until a balance was reached— a process which had the oceanographers transfixed with interest, for the saltiness of Earth’s oceans, stable for many millions of years, was not well understood.