Encounter With Tiber

by Buzz Aldrin

  “Is there something especially French about a gas giant around Alpha Centauri B?” Lori asked, curiously.

  “No, I don’t mean after the spirit of the Republic. I like it because that’s my daughter’s name. It’s as good a reason as any other. But I do think our station commander is right; unless we suddenly have a way of finding thousands or millions of planets, everyone will want the new planet to be named after their particular god or cause, and the IAU probably won’t get to talk about much else until it’s finally settled—if it ever is. Meanwhile, I do believe Jiro has something to show us.”

  The Japanese astronaut smiled shyly. “I’d like François to begin. His insight led me to my results.”

  François, who had gotten that information from his friends at CNRS, began, “First of all, the burst of base eight numbers are coming in groups of 16,769,021, with a longer break between each group. And what makes that interesting is that some bright people ran it through a simple factoring program and discovered that it’s equal to 4093 times 4097—two prime numbers.”

  “Uh, excuse my being dumb, but this means …?” Lori asked.

  “Since a prime number isn’t evenly divisible by any other number, if you’re transmitting a grid-type pattern—say a picture or a chart—and its size is the product of two primes, then there are only a couple of possible arrangements for the numbers in the grid. If either number were not prime, there’d be a very large number of possible arrangements, and that would mean you wouldn’t be able to figure out what the picture was a picture of.”

  Chris jumped in. “Like, suppose you know that you’re getting a list of the cells of an individual grid, but you don’t know what shape the grid is—only that they sent you sixty cells. Well, sixty could be the number of cells in a five-by-twelve, or a six-by-ten, or fifteen-by-four, or for that matter a two-by-thirty or a three-by-twenty grid. And if the number were much larger, and the product of many different numbers, you could spend a long time looking for a way to arrange the grid that made sense. But suppose they sent you seventy-seven cells; that can only be a seven-by-eleven grid, or an eleven-by-seven that’s the same grid lying on its side. So what this means is that they’re sending us pictures, tables, charts, something like that—and every picture is four thousand ninety-three by four thousand ninety-seven dots or pixels or whatever.”

  Denisov nodded and said, “And it’s more evidence of their alienness. That’s the first prime greater than four thousand ninety-six times the first prime smaller than four thousand ninety-six—and if you write four thousand ninety-six in base eight, it’s a one followed by four zeros. So it looks like when they laid out their grid, they set it up to come out close to what they would think of as ‘round’ numbers.”

  “Has anyone tried to assemble the pictures yet?” Lori asked.

  “I thought you’d never ask,” Jiro said. “I have a feeling that everywhere on Earth people are showing this to each other, but they don’t quite have the nerve to display it publicly. My guess is that at least a hundred people have tried the same thing I have. After all, the only reason we have a copy of the signal is because we happen to be sitting at the receiving antenna and we sort-of-accidentally happen to be recording it; the ground stations we’re transmitting it to not only have copies, they also have a lot of people who are paid to analyze it—whereas I’m just doing it in my spare time. So I’m sure other people have hit on the solution I have, which is this: suppose we assume that the beeps and honks, as they’re calling them, really do represent binary one and zero, and that therefore the groups of three are base eight numbers. There are really only four possibilities as I see it: either you read the group of three left to right, or right to left, and either you read beep as zero and honk as one, or vice versa. On that basis, for example; ‘beep beep honk’ could mean one, four, six, or three. What occurred to me was this: what if we just make a guess that the numbers represent values of bright and dark on a 4093 by 4097 grid? Then there are actually only eight possible images that each frame might be, and furthermore half of them are black-for-white negatives of the others. Well, then, it wasn’t all that difficult to set up a program to compute an appearance for all 16,384 frames eight times—they do things much more complicated than that in a matter of a few minutes in the new virtual reality games in the arcades, you know, and we have a good deal more computational power available than they do. And then one further idea struck me—now I have these eight sets of frames … what could they be? Photographs? A photographic image of a book page, perhaps?

  “The first thing I noted was that quite a few of them in this group”—he clicked on the shared screen and showed the group—“look like kind of an oddly notated star map.”

  “That’s what it is, all right,” Chris said. “Those are the principal pulsars near us, with lines proportional in length to distances to us—or more likely to Alpha Centauri. Unless we have a precise tool for measuring the length of those lines on the screen, the differences aren’t going to matter much in this scale of a picture.”

  Everyone turned to look at him, and he said, “I had something like that on my bedroom wall as a kid—the poster version of the plate that went on our Pioneer spacecraft, way back in the seventies. I fell asleep looking at it, a lot of the time. And that’s so close to the same pattern, that, since in astronomical terms we aren’t very far from Alpha Centauri—”

  “I see,” Jiro said. “Well, then, no doubt a lot of people have figured that one out, too. And perhaps from that we’ll be able to crack their system of numbers and measurements. Certainly there’s something that looks a lot like writing, right next to lines that look like they ought to be dimensions. Anyway, it occurred to me that since several consecutive pictures were pretty similar to each other, there might be a reason for what seemed like a lot of redundancy—I think this is a movie.”

  “A movie?” Lori said. “So each of those sixteen-million-or-so-number sets is a description of a frame?”

  “That was the idea I had,” Jiro said. “And here’s the result: we can only guess at the intended projection speed, at least until we figure something out about their writing, but this looks convincing to me.”

  The screen popped into focus, and they saw eight creatures climbing into what had to be a spacecraft. Two of them seemed to be very tall and thin, covered with fine fur, with big ears like a bat’s. Two others, of the same body shape, were smaller. Two were square-built and strong looking, like gorillas, with strange high ridges that stuck straight up from their shoulders and a high, hair-covered crest that rose from the top of their head like a mohawk. Their fur seemed to be thicker, longer, and coarser than that of the taller ones, and very dark; they had thick beards under their jaws, almost like manes. Two others had the same dark and heavy fur and were also squat in build like an ape, though they stood as erect as any human; they were quite short and had no crests or beards.

  As the ISS crew watched, the creatures waved and got into an odd, thick-bodied rocket ship that lay on its side; the rocket floated straight up a long way, and then they saw the engines fire.

  The image cut to a rendezvous with something that looked like a space station in orbit: a torus or ring shape impaled on the end of a column sticking through its center. The little craft docked at the tip near the torus, a quick interior shot showed the alien crew getting into the bigger ship, and then the little craft undocked and went away. Abruptly, on the big structure, the end away from the torus fired a great stream of white-hot stuff into space.

  The first of the crew to speak was Haldin; she said only, “Jiro, I would have to say that if your interpretation isn’t right, it’s the damnedest coincidence in history.”

  The rest of the first forty seconds or so showed them deploying a light sail, sailing away from Alpha Centauri with a couple of gravity assists, making their way to the solar system, and descending to Earth. “That map is Suez and the Eastern Med,” Lori exclaimed. “Even though it seems to be upside down, anyone would recognize it!”r />
  “Yes,” Jiro said, “and if the blinking dot is the landing site, then I guess they landed somewhere in the Jordan Valley.”

  An abrupt cut showed another spacecraft also departing Alpha Centauri. “What do you suppose that one is?” François said. “It just streaked off the screen.”

  The image showing the landing site was repeated; then there were pictures of yet another type of spacecraft departing Earth, and abruptly it cut to three arrows: one pointing straight down at an image of the Moon; the second at a spot on the surface of Mars, near the bottom but at an angle; and the last pointing to the faster-moving inner moon of Mars, Phobos.

  “What do you suppose that means?” Lori said. “It looked like the Moon was upside down, and Phobos was going backward, so I guess they use the bottom of the map for north and the top for south. So they’re saying they went to the south pole of the Moon, to Phobos, and to somewhere near the north pole of Mars?”

  “If an arrow means the same thing to them it does to us,” Chris pointed out. “Maybe they’re talking about something that came from there, or it’s their symbol for where everyone is buried, or where they put the biggest cathedral or their equivalent of the prime meridian.”

  The camera cut again. It showed what appeared to be a simple, squat box with a cylindrical plug in the corner of one side, and a square plug in the center of an adjoining side. Then the screen filled with text—“That really does look like it has to be alien writing,” Peter said. “Directions for how to operate something that’s shaped like that box?”

  “Or how to pray to the sacred box, or how to build the alien version of the clothes washer,” Lori said. “The anthropologists and linguistics people are going to have a great century or two working on all this.”

  The camera cut again to show, one more time, arrows pointing to somewhere on Mars and probably to the south pole of the Moon. Then it showed a sequence of spaceship departures, one after another, nine in all, each followed by a quick designation of a star from pulsar positions, an image of the star’s planetary system in which one planet was marked with an odd symbol, and an arrow pointing to somewhere on a planet. Finally it showed thousands of aliens, some like the ones in the first pictures, descending through huge corridors. Then it showed a flock of spacecraft leaving orbit and repeated the picture of the box.

  “Notice that their world is in orbit around a gas giant?” Jiro said. “My first thought was that that confirmed it, but watch the last shot here.” The last shot showed eleven solar systems, ten of them arranged around a central one. Ours was one of them; the central one had a double star, with gas giants circling both of the two stars.

  The larger gas giant circled the larger star, and around that gas giant there was a single moon, marked with a strange twinkling symbol. The smaller gas giant, orbiting the smaller star, was circled by three moons, two in roughly circular orbits and one in a highly elliptical orbit; this last moon was marked with another, different twinkling symbol.

  “Looks like they agree with you, Chris,” François said. “They show a moon in a highly elliptical orbit, around a gas giant, circling Alpha Centauri B.” The picture stopped as abruptly as it had begun.

  “Well, that makes sense,” Lori said. “They put their home system in the center.”

  “Well, if nothing else, that’ll get all the astronomers busy,” Chris said. “And there must be a hundred or more planets and moons between all the systems they depict there. Once we figure out how to read their notation, there’s going to be plenty of names for everyone to put on things.”

  “Hah,” Haldin said gloomily. “There are any number of people out there who can come up with a list of a hundred things they want honored. Their countrymen, their gods, probably their crops. I rescind my previous claim. It’s not going to be decades for the IAU to sort things out, it’s going to be centuries.”

  “Why do you suppose this, uh, alien cartoon isn’t all over the airwaves already?” François asked.

  “Probably because everyone who has thought of doing this with it—which means undoubtedly someone almost everywhere—is hoping to break the alien code before announcing,” Jiro said. “Figuring out that it’s a movie will get you on the air for twenty minutes. Figuring out what the movie says—well, that will put you in the history books for a long, long time.”

  The rest of that last work shift was uneventful, but when everyone arose the next morning, the news from Earth was a mixture of the astonishing and the silly.

  Suddenly every television reporter on Earth wanted to interview every astronomer. And since the preliminary results had overthrown the ideas of so many of them, many astronomers, receiving public attention for the first time in their lives, gasped, stammered, or simply refused to talk.

  Just the existence of planets in the Alpha Centauri system at all had been enough of a shock to many of them, Chris thought. Since the distances between the two stars varied by a factor of three, tidal forces varied by a factor of twenty-seven; debate had swung back and forth for decades about whether this would sweep the system clear of the primordial planetesimals out of which planets accrete (so that there would be nothing there) or prevent them from accreting at all (so that there would be thousands of very small bodies), or cause them to accrete more readily (so that there might be a small number of very large planets). Well, Chris thought, here’s where all the astronomers and planetary scientists get to find out who guessed right. It sure didn’t look good for the two “no planets” theories.

  All that attention focused on the astronomical community had also meant that no action by an astronomer was going to be overlooked. Taking advantage of this, an Italian astronomer, Vincente Auricchio, had published via the Internet, and then called a press conference just twenty minutes later. Everyone on the ISS took the extra few minutes to watch this one. Auricchio spoke English (the language of the international media ever since BBC Overseas TV and CNN divided the world between them) with just a trace of an accent; it was as if he had spent all his life preparing for a media event.

  “Well,” Auricchio was saying, “I see no reason to pretend to a wholly inappropriate modesty, or to beat around the bush, as you say in English. Western civilization is the greatest civilization the Earth has ever seen, and the West learned to be civilized from Italy, and the Italians learned it from Rome. It is thus no accident that I, a life-long citizen of Rome, have found the key to the alien message; I simply compared the orbits figured by the crew on the International Space Station with the orbits described in the animated message from the Tiberians, and by assuming one was a translation of the other, broke the code of their system of representation. Then I turned to—”

  “Excuse me,” the reporter from the New York Times asked. “You said the message from the—”

  “The Tiberians. The inhabitants of Tiber. Which is the inhabited moon that circles Juno, which circles Alpha Centauri A. As I was saying, by comparing the orbits that were calculated by Terence, Raymond, and Kawaguchi—and I might note that Terence and Raymond each have Italian ancestors, according to their biographies—”

  “And I like Italian food,” Jiro said. Everyone shushed him.

  “—I was able to figure out their system of time notation, hence where those new planets should be and should have been for thousands of years into the past. Now as it happens, the university here at Rome has a quite good system—in my opinion, the best in the world—that preserves a digitized version of virtually all the astronomical photographs taken in the last century and a half. It was therefore very little trouble to call up into my computer all those photos which ought to show those planets and their moons, if the resolution was high enough; select those with high enough resolution; and by combining these several thousand photos, especially those from the American Hubble Telescope, I was able to show that these few dim white dots, which were always mistaken before for very faint stars at very great distances, were in exactly the right places to be those planets and moons—and here is my list of
what I have extracted the sightings of from the record, ladies and gentleman, the first confirmed observations of planets around Alpha Centauri A and B:

  “Alpha Centauri A’s planet Juno—which seems to be of a mass about two hundred and fifty times that of the Earth, or three-quarters of Jupiter, and orbits its primary at a distance somewhat greater than one astronomical unit;

  “Juno’s moon Tiber, which is in a twenty-six-hour orbit around the giant planet, is just slightly more massive than the Earth, and is clearly designated in the message as the place from which our alien visitors came or intend to come;

  “Minerva, the gas giant circling Alpha Centauri B at a distance a bit less than an astronomical unit, with a mass of one hundred thirty-eight Earths;

  “Alba Longa, the moon of Minerva on which the transmitter is mounted, about one and a half times as big as Mars, in a highly elliptical orbit;

  “Hercules, a moon of Minerva about the size of Io in our own solar system, in a fairly wide but nearly circular orbit;

  “And Minerva’s nearest moon, the hardest one to see, which I have only about a dozen images of—but more than enough to confirm its existence. This moon I have named Caesar.

  “My assistants will pass out complete packets of information on these new worlds—discovered like so many other new worlds, by a proud Italian—and of course I shall be delighted to answer any questions you may have about my deciphering of the alien message or about the little we can know so far about these new worlds.”

  The Times reporter, a tall, thin man, stepped forward and raised his arm again. With an impatient sigh, Auricchio pointed at him, and the reporter said, “If I may ask, the names you have given these celestial bodies—”

  “Are entirely my right as discoverer. I will not make the mistake of my great compatriot, Columbus, who failed to have the new lands named after himself; it was only sheerest luck that ‘America’ was also an Italian name. I have chosen my names as grand ones from Italian and particularly Roman traditions; that is as it should be. Western science made this discovery possible, and Italy leads the West intellectually, as it has always done. If other nations wish to have planets of their own, they had best hurry and discover them—but I warn you, my assistants and I are already at work on finding the planets of the other solar systems designated by the Tiberian message. Next question, please?”