Encounter With Tiber

by Buzz Aldrin

  For that matter, the safest place to examine an object or document was often in situ; the less it was transported, the less the risk to which it was exposed. This had all become bitterly clear after the destruction of the Encyclopedia on the Moon. Dad had been an astronomer, Xiao Be a pilot, and neither had made any interesting observations or picked up a single clue for later researchers. They had merely been sent there to grab a treasure, Indiana-Jones-style. Back in 2010 it might have cost the nations of the world two extra years to train a team of archeologists, computer scientists, and cryptologists for lunar operations, then design the equipment to attempt to read the Encyclopedia in situ. They hadn’t been willing to pay that price then, so now they had spent a hundred times as much money and ten times as much time to get here, and until (much later) we got down to the Encyclopedia itself (assuming that that was what was under the ice half a kilometer from the Tiberian settlement) the human race would still not know whether they had lost that precious data forever.

  The problem was compounded by the scant knowledge that had been available about the Martian arctic. The actual conditions in which they would be digging had had to be painfully ascertained, measured, studied, and thoroughly understood over a period of many months, by Doc C, Yvana, and the rest of the team of experts that had already wintered over, before there was even any point in having the Tiberian archeology experts on hand for this next phase.

  But now, so far as could be told, we knew everything about digging in a frozen Martian lake that we might need to know, and now, no matter what happened, trained eyes would be there to see it. So after months of waiting until we were really, truly ready, that morning we went to work with perfect confidence. We laid out a grid, using a laser transit of squares half a meter on a side, all around the site. Then, using a depth-gauged laser that constantly monitored how deep it was going, we cut out each square to a depth of half a meter. Finally, we inserted the “periscope”—a rod with mirror mounted inside its tip to horizontally deflect the cutting laser’s light—into the grooves we had made, and cut the block free from the bottom. With friction grips we then lifted it out and put it into an insulated, sterilized box for the rest of the team to study.

  The blocks were large and awkward, but though the mass was the same as it would be anywhere—125 kilograms—the weight, which depended on local gravity, was only 91 pounds (as opposed to the 275 it would have been on Earth). Thus the work was only hard physical labor, combined with a need for fiddling exactitude in removing blocks and labeling boxes. By the time we broke for lunch, with the sun about an hour past noon, Olga and I had cut out and boxed nineteen blocks, which was the best anyone had done; Pete and Jim were second with seventeen. Gander clapped me on the back and declared that we had saved the crew’s honor; he and Fleurant had only managed to cut out eight, tying with Ilsa and Tsen.

  As we ate in the largest of the overnight shelters, the analysis crew joined us. It was a tight fit, but we all wanted to hear what they had found so far.

  They could do the basic processing on a block much faster than a crew could cut one out, and what they did required special skills; thus there were a lot fewer of them than there were of us. Though she was normally shy and didn’t say much, Kireiko was apparently elected to tell everyone the results. She sighed, then said, “Well, you know, you always hope for something startling the first day. What we’ve done so far is send each block through a CT scan and an NMR scan. On the average each block has about two hundred specks of some organic material—which could be microscopic bits of dead Tiberians, or Martian life, or just various chondritic materials. The fact that so many of them are close together in size would tend to argue that they’re actually spores, and if that’s what they are, then they’re either Tiberian or Martian, which we can probably get from looking at the DNA. If it shows up as Tiberian, great; if it isn’t earthly or Tiberian, well, we’ve just discovered life on Mars. More likely we’ve discovered chondritic dirt.

  “The other thing, which I’m sure will get Nari excited, is that there are a lot of microbubbles in there, and some preliminary probing suggests that just maybe the pressure in there is a bit higher than ambient.”

  Dr. Narihara Nigawa, probably the most distinguished scientist we had, sat straight up as if he’d received an electric shock, thumping his head against the low ceiling in the corner where he was eating, and spilling his water all over himself. It took him a moment or two to get reorganized and recover his dignity before he said, “All right, that’s not fair, Kireiko. If I’d choked on my sandwich you all would have had a hell of a time explaining it back home. How much higher was the pressure in the microbubbles? And what was their composition?”

  I had rarely seen Kireiko’s puckish smile before; I realized that I had made the mistake a lot of people make of assuming that quiet and shy people don’t have senses of humor. “I should have guessed you would ask about the composition. I was going to save that part to really startle you. As kind of a followup to the surprise about the pressure—”

  “Will you tell me, please?” Nari said.

  “I think you’d better,” Gander said, grinning, “or I won’t be responsible.”

  Kireiko’s smile grew broader. “Well, then, if you really want to know … pressures looked to be about thirty-five millibars, and the chemical composition showed about one and a half percent free oxygen.”

  We all jumped at that a little bit. Ambient pressure on Mars today is something over five millibars. Oxygen is 1300 ppm, or 1/100 of what Kireiko had just said. But Akira sat up straighter than anyone else and said, “Well, at the risk of its looking like a Japanese conspiracy, I’d have to say that Dr. Nigawa’s ideas are undoubtedly looking better and better. At least from a meteorological perspective.”

  Fleurant nodded. “Even I would have to concede that.”

  “For those of us who are not up on our studies,” Olga said, “do you suppose you could tell us what this is about?”

  “Sure,” Nari said. “I think that when they came here they tried to terraform Mars, probably because the protein incompatibility was so great a problem on Earth that it seemed simpler to just come here and plant Tiberian life if they could. And then the process stopped, either because they died—or possibly because it killed them somehow. Without their intervention, Mars reverted to what it had been. The worldwide discontinuity in frozen deposits and permafrost is caused by everything thawing to that depth and then refreezing.”

  “I should add I don’t disagree with all of that,” Fleurant added. “It’s just that I think it’s simpler to account for it all by saying that sometime after the Tiberians moved to Mars from Phobos, and then died, there was a major thaw and refreezing. You would expect air pressure to be much higher during refreezing, so the pressure of the bubbles doesn’t pose any problem to my explanation. But the free oxygen is something else. The only constituent of the atmosphere that should be undergoing gross changes in quantity, during a thaw, is water vapor. Free oxygen looks like they managed to get something growing in the open air and converted a little bit of the carbon dioxide. Nari is beginning to persuade even me.”

  It took Kireiko and Tsen a very long time to extract enough of the little pellets within the blocks of ice to begin a real study; meanwhile, we kept cutting blocks. Our five crews of two could cut out about three hundred blocks a day, now that we had enough practice and had perfected our techniques. The trouble was, the Tiberian site was about fifty meters square, and the tops of the Tiberian artifacts were just about four meters below the surface, so a whole month went by and we were still more than a meter, on the average, above the roofs of the huts, the side of the lander, and, half a kilometer away, the Encyclopedia that we were nominally there to get.

  One evening, as we shared dinner in the mostly empty hab that everyone called the “dining hall” because it contained five farms and a sort-of kitchen Doc C. had rigged up, Nari said, “I wonder if you all would feel I was throwing my weight around, as head of the science t
eam, if I put in a request to Mission Control to borrow Jason, Olga, and Yvana tomorrow? There’s an idea that I’d really like to investigate. It will only take one day, one tractor, and some of the exploratory gear.”

  Gander shrugged. As head of the station he had the ultimate say in such things, but normally he deferred to Nari in any decisions that involved scientific work. “I’d say go ahead. In fact if you’ll ask permission to take me, too, it’s a deal. I could use a day of not cutting out ice blocks. I was going to suggest that seeing as we won’t be getting down to the layer of the major objects till after the Five Alpha crew gets here, and we haven’t found a lot of interesting things after the initial surface discoveries in all those blocks of ice, perhaps it’s time for a little variety in our lives. Maybe we could start taking a day of rest here, say, every seventh day, since that’s traditional for several of us? And Nari, if you can use extra hands productively, I’d like to let the whole team do whatever you have in mind.”

  Nari chuckled and stroked his chin thoughtfully. “Well, now, that’s an interesting question. Yes, I could use a lot of hands; it’s a surveying job. Okay, I’ll include everyone in the request. I think I know where to look for another Tiberian site, less than twenty kilometers from the Encyclopedia site. And if we find what I think we’ll find there, well, then, I would say my case is pretty well confirmed, though I will want to test one more prediction after that. So it might be great fun to have you all there while I triumphantly point at the X-ray scatters I want Yvana to do, and then say ‘See, it was obvious to me all along.’ On the other hand, should I prove to be wrong, I’m not sure I want you all there to watch Paul Fleurant jumping around and shouting ‘I told you so.’”

  Ilsa leaned back and said, “Well, Nari, now that you have assured yourself that all of us are curious, why don’t you tell us about your idea?”

  “Am I that transparent?”

  We all nodded.

  “Well, then … it goes back to a lot of my early work on the Moon. The question for me is always, what does it look like these people were trying to do? So put together the basic facts—protein incompatibility. Nobody hangs around trying to give themselves hundreds of bizarre syndromes, and that’s what they had: damaged cells in every part of the body, failing joints, brain lesions, some organs badly atrophied or hypertrophied. They didn’t want that to happen; I think we can assume the aliens are at least that much like us. So they didn’t spend all those years on Earth entirely by choice, and finally they left—something changed so that they could or because something we haven’t identified made the situation totally impossible. Now look at the technology mix—it doesn’t look like a plan to me, it looks like what would happen if you suddenly forced the average small town back home to get along with just whatever was within city limits on a given day. Some pieces of very high-tech stuff, some fairly crude, and a lot of cobbled-up fitting of low to high. So my guess right along has been that their Earth colony failed, and for whatever reason they couldn’t try to go home—certainly the landers wouldn’t have had the range, which is why it seems very likely to me that the wreckage all over Phobos is what was left of the main ship. So you can’t survive on Earth and you’ve got to survive in the solar systems. You have a lot of high-tech devices, but only a limited ability to fix them and no ability to make more. And if Earth is deadly to you in the long run, well, everywhere else is in the short run. Well, then, what do you do? You try to create a long-term habitable place for yourself and your descendants—no matter how hard that is to do. And since they were roughly like us, well, what’s the most terraformable world? Okay, now we know why they came to Mars. And why Korolev? Well, that’s where my guess comes in, in a big way.

  “I think it’s three factors. First of all, they really needed somewhere with surface water ice, so that they wouldn’t have to extract water from permafrost. That argues that maybe their machines were breaking down after several decades of trying to survive in space. They wanted somewhere where their descendants could make it, even if they had to go really low tech. Well, Mars has almost no water in the equatorial regions, and not much more than none at the south pole. If you go all the way up to the ice cap, here in the arctic, then in the first place since a large part of that is going to melt, you’re SOL if you don’t place your base just right, and in the second place you have to deal with extreme arctic conditions—almost an Earth year of daylight followed by almost an Earth year of night, among other things. So what you want to do is go to the place farthest south in the arctic that has a significant amount of water, preferably water that isn’t going anywhere too fast while it’s warming up. And here we are—the best combination of southerly location and confined water available on Mars.”

  “Well, so far you’ve shown that they’re at least as smart as you are, Nari,” Fleurant said, teasing.

  “And the proof is incontrovertible,” Tsen added, “because Nari and the Tiberians both ended up at Korolev.”

  Nari ignored them and went on. “So, what else do we know about them? They had almost no ready-made shelters—my guess is that the two pressurized shelters on the Moon were all they had, probably one for each lander. But apparently if they had water, or even a little bit of chondrite, they could manage an adequate bioenvironment, provided they could seal it. So they used the lava tubes on the Moon, and they bored into Phobos, and then sealed those spaces with fused rock and crudely machined doors that I would bet were made in a machine shop on their starship.

  “Now, take Mars. Low pressure and moderate radiation less than Phobos and the Moon. And ask the other question: why does anyone who’s planning to live on a planet, that they’re going to warm up to a comfortable temperature, move onto a frozen lake? My guess is, because they weren’t going to stay on the ice forever. There was something more suitable somewhere nearby. So I started looking into local geology, and guess what?”

  “You think you know where they were planning to move as a permanent base,” Kireiko said. “And you want to go see if they got any construction done there.”

  “Exactly. Korolev is an almost classic case of an impact in permafrost. The meteor liquefied the soil and sent it outward in a big ripple, the ripple lost momentum and ‘froze’ into place, and then as water in the soil redistributed itself and refroze, the terrain around the crater softened and became lumpy. Wherever there wasn’t enough water left, things collapsed or caved in, and the crater itself filled with water and later ice. Well, structures like that often have voids in the crater wall—”

  “Caves,” Fleurant said. “You think there are going to be caves on the crater wall, where the Tiberians were planning to dig in.”

  “Not only that,” Nari said, “but Akira and I did a few computations that I think are very interesting. Nine thousand years ago or so—if you accept the few pieces of terrestrial wood and wool found on the Moon as evidence of the date—Mars’s obliquity was considerably lower than today’s. And the climate models are pretty uniformly in agreement that if Mars has low obliquity, it tends to have a thin clear atmosphere and the poles act as a cold trap for water; if Mars has a high obliquity, it tends to have a thick, dusty atmosphere and probably even some liquid water. So from a standpoint of terraforming—”

  Tsen raised her hand. “I don’t suppose a mere doctor and biologist can understand obliquity?”

  “Tilt toward the Sun,” Nari said. “Low obliquity means the poles point straight up and down, perpendicular to the orbit. High obliquity means it’s really tilted steeply. Since the Martian atmosphere freezes at the poles, and weather is caused mainly by temperature differences, with low obliquity, one season is very much like another, everything that goes to the pole stays there so the air pressure drops, and temperature differences stabilize so there’s not much to stir up the dust and almost no air to hang it in if it did stir up. In high obliquity the poles tilt far over, so that when one of them is pointed toward the Sun it gets a lot of heat, and at that ‘summer pole’ the carbon dioxide evaporates an
d stops acting as a cold trap for water. Meanwhile the winter pole gets colder, but that means a bigger temperature difference and so there’s more wind in a thicker atmosphere, more dust to help absorb sunlight and darken the ice, and so forth. And since the winter and summer poles keep trading roles on a half-year cycle, pretty quickly you’ve got a lot of air moving back and forth, not much of a cold trap, big dust storms, and so forth. And what I was about to say is, if you were going to terraform—or I suppose Tiberform—Mars, you really want to arrive during high obliquity. The poor Tiberians were here at a relatively bad time to do it, when if anything happened to them, the natural equilibrium of the system was strongly biased toward freezing up.

  “Also, Mars has what’s known as poleward migration of water. Water tends to become part of permanent frozen deposits, and since the higher the latitude it’s at the smaller chance that it will ever thaw, over long periods of time the arctic and antarctic are always gaining water. If you have thawed water anywhere on the planet, it migrates faster. So here’s what I think happened: the Tiberians got partway with their terraforming, and then something happened so that they couldn’t continue. As soon as they weren’t pushing the climate toward warmth and thick air, things started back toward the normal—and all the water they liberated came up north and helped fill up the crater over a period of just a few years, covering what was left of their settlement and preserving everything under a blanket of ice. I’ll bet the Tiberians below the discontinuity are the ones who died and were buried in the ice before the colony failed—and will be in almost perfect condition—and the ones in the huts died where they were and lay there until, that night or ten years or a century later, all that water fell back out of the north polar hood and covered them.