by Jerry
If there had been a blindingly obvious signal, such as the first five prime numbers repeated in a very powerful broadcast, the real-time scanners would have caught it as it came in. So, if there was something buried in here, it was likely both a weak signal and a subtle one. Still, there are ways you can tell if something has information content—Zipf plots were one such tool—and other ways, such as Shannon entropy scores, for determining how complex the content is, even if you couldn’t decipher a word of it.
Emily knew the chances of finding anything were slim, but, nonetheless, she kept designing new techniques, tweaking algorithms, modifying filters, and—
—and there it was.
My God.
She’d found it.
She’d found Gordo.
And just like Gordo—just like sauropods, by far the largest land animals ever to exist—it was huge. Gigantic. Not just terabytes. Not petabytes. No: more even than that. Exabytes—quintillions of bytes. She double- and triple-checked, ran some more tests, and then checked again, just to be sure. There had, after all, been numerous false alarms related to SETI signals. The first pulsar discovered in 1967 was dubbed LGM-1 for “Little Green Men One,” because it appeared to be an extraterrestrial beacon, and, in 2015, a signal candidate from the Parkes Radio Observatory in Australia turned out to just be noise from the microwave oven in the lunchroom.
But, when Emily was totally sure, she picked up her phone and said, “Call Hannah Plaxton.”
“It’s after 2 a.m.,” the phone replied. “Are you sure you want to call so late?”
Emily was surprised at the time. Still: “She’s an astronomer. She’s used to being up at night.”
“She’s a radio astronomer,” replied the phone. “She works during the daytime.”
Well, the phone had her there. “All right. But if Hannah comes online overnight, wake me. And book me a flight for tomorrow morning to go see her.”
In 1980, Carl Sagan had popularized the idea of an Encyclopedia Galactica, opining that aliens might someday be so kind as to beam such a thing to us. Back then, Sagan probably considered the Encyclopedia Britannica the pinnacle of human knowledge, and not just because he was a contributor to it. But for all his forward thinking, Cosmic Carl was a product of his time; no encyclopedia could properly systematize all that humanity had learned, although the few remaining Wikipedians still gamely tried.
In 2009, SETI pioneer Seth Shostak started advocating that if humanity were to transmit anything to the stars, it might as well transmit everything, broadcasting the whole World Wide Web. The modern Web would take months to send via microwave, but the whole darn thing could be beamed to a specific target via optical broadband in less than a day.
But, it turned out, the denizens of 47 Ursae Majoris had beaten us to the punch, sending what had been dubbed the Reticulum—their alien counterpart of our World Wide Web.
“My predecessors at my lab pioneered automated picture captioning,” Emily said. “It’s such a common feature in cameras now, we tend not to think about it. But the techniques they developed are a big part of what’s letting us make sense of the Reticulum.” She was standing next to a wall monitor at the Interstellar Communications Society, an image of three of the aliens filling it.
Hannah Plaxton looked down at the caption. “ ‘A doctor treating a patient,’ ” she read aloud.
“That’s right,” said Emily. She gestured, and text labels appeared over the image, identifying the specific objects in it: Doctor. Patient. Individual. Tray. Equipment.
Hannah pointed at the “individual.” “Why isn’t this guy mentioned?”
Emily nodded. “The captioning is done with neural networks; they learn as they go along. The more pictures they looked at, the better they got at picking out what was relevant. Look at the eyestalks on the two aliens who are mentioned in the caption. On the doctor, they’re facing toward the patient. She is looking at the patient; the patient is the focus of her attention. And see the patient’s eyestalks? They’re turned toward the doctor. Those two aliens are regarding each other. But the third guy? The one not mentioned in the caption? Sure, the software realized that he’s there, but he’s not looking at either of the other two; his eyes are turned to look at something out of frame. And so the algorithms decided he was just a bystander accidentally caught on camera, not part of the action being depicted.”
“Interesting,” said Hannah. “In most of our own pictures—ones taken by humans—the people in the frame are looking not at each other, but at the camera.”
“Right. Which is so artificial, when you think about it. In fact, if that ever happens on a TV show or in a movie, we’re freaked out; an actor almost never turns directly toward the camera. But it doesn’t seem that any of the pictures in the Reticulum are posed photographs. And that says something about their society, I’m sure. In any civilization, cameras are going to become dirt cheap—they’ll be everywhere. And storage will become so cheap, as well, that you’ll record everything.”
“But what happens to privacy?” asked Hannah.
“Maybe the aliens never valued it in the first place. Look at what little clothing they wear. It’s all functional: sometimes a sash with storage pouches, protective gear, ornamental ribbons. No one part of the anatomy is always covered, so there are clearly no nudity taboos. And there are plenty of photos in which the individuals in the background seem to be having sex.”
“And they don’t desire privacy for that, at least?”
“Maybe the reason we started desiring it was because, while doing it, we’re particularly vulnerable to sneak attack. But with cameras recording everything, you’re probably perfectly safe all the time—so, what the heck. For us, any picture in which people were having sex, whether it was the foreground of the image or the background, that’d be the thing we focused on. But it’s clear from the eyestalks that that particular act is given no special importance. It’s not ignored—it’s not that every alien demurely swivels his eyestalks away whenever he sees a couple of others going at it; there are plenty of pictures in which others happen to be looking at what’s going on. But it’s not disproportionate.”
“Well, that explains why the Reticulum is smaller than our World Wide Web: no nudity or sex taboo equals no pornography. You could shave a zettabyte off our own Web if it didn’t have all that stuff.”
“Exactly. And there’s more. The aliens have three arms. Males have two on the left and one on their right, and females have the opposite configuration. It’s a weird dimorphism, but you can almost see how evolution selected for it. They sent us numerous pictures of family groups walking as woman-child-man. They don’t hold pincers, but the woman puts her left pincer on one of the child’s shoulders, and the man puts his right pincer on the other, and the child is protected, while the adults each have two arms on the outside to do things with, right?”
“Ah, Okay,” said Hannah.
“The algorithms were able to divine some additional meaning from that. Whether it’s conscious or not, the aliens clearly place things that are precious to them adjacent to their single hands. We’re calling them ‘twoside’ and ‘oneside,’ and anything that’s of great value or needs protection seems to be on the oneside.”
“The algorithms did that? Starting with nothing?”
“They didn’t start with nothing. They started with hundreds of millions of images, and looked at each one with a patience and a depth that no humans could have.”
“Data mining for the win,” said Hannah.
“Exactly.”
It was finally Emily’s turn to take the stand. Hannah Plaxton asked her a series of rehearsed questions about the data mining that had discovered the Reticulum. But then it was Piotr Sudeyko’s turn to cross-examine her.
“Dr. Chiu,” he said, “I’ve been very impressed by the naturalness of Ursula’s speech.”
“Thank you.”
“You really have done a remarkable job, producing an alien AI avatar that makes the Re
ticulum as easy to query as our own World Wide Web.”
“Thank you. It was a team effort.”
“It’s astonishing, really. I was given to understand that the sort of universal translation Ursula performs is impossible. Can you explain to the good women and men of the jury how it was accomplished?”
“Certainly. We had our first big breakthrough in spontaneous speech recognition in 2010, using fully connected deep neural networks, or DNN. For deep learning, you keep throwing more and more samples at the neural nets, and, by comparing one to another, the nets eventually figure out word semantics, sentence semantics, and knowledge modeling.
“One of the keys was realizing that semantic intent is better defined at the phrase/sentence level, rather than at the word level. After all, the meaning of a single word is often ambiguous—is a bat a flying mammal or a sporting club? But a phrase, or a sentence, or even a whole document, contains rich contextual information that we leverage. And, of course, the whole web, whether it’s ours or theirs, contains countless Rosetta stones. There are only a handful of ways to lay out the periodic table, for instance, and any technologically advanced civilization is going to have some sort of representation of it.
“So, our neural nets just kept looking to see which alien words were juxtaposed frequently with which objects in accompanying illustrations. It’s a statistical game, but if you play it long enough, you win.”
“I see. And I suppose for simple things it was fairly easy to come up with a translation table, no?”
“That’s right. For instance, they sent thousands of pictures of mineral specimens, and by examining text linked to those pictures, not only were the neural nets able to figure out the alien words for specific types of minerals—their term for ‘quartz,’ say, or for ‘diamond’—but eventually to figure out general terms, including ones with fine distinctions that even most humans are unaware of, such as the difference between a ‘rock’ and a ‘mineral.’ ”
“I confess that I myself don’t know the difference.”
“A mineral is homogeneous, with a specific crystalline structure; a rock is made up of multiple minerals.”
“Ah,” said Sudeyko. “And so, I suppose, by the same technique, your algorithms divined the alien words for, say, ‘stream’ and ‘river.’ ”
“That’s right.”
“And for ‘pond’ and ‘lake.’ ”
“Yes, that’s correct.”
“And ‘sea’ and ‘ocean.’ ”
“Well . . .”
“Yes, Dr. Chiu?”
“Of course, our technique can only translate things for which there are terms in both languages. I’m sure you’ve seen the pictures and maps of their world they sent us. It’s a much drier planet than our own. There are no seas or oceans—and so no continents or large islands. A map of their world’s surface looks like a slice of Swiss cheese, with the holes being lakes.”
“Aha,” said Sudeyko, smiling in a way that, to Emily, looked triumphant. He turned to Judge Weisman. “Your honor, I’d like to recall Ursula to the stand.”
Weisman announced a fifteen-minute recess. Once it was over and everyone was reseated, Piotr Sudeyko said, “I have a few more questions for you, Ursula.”
The avatar’s eyestalks swiveled to follow him as he paced in the open area in front of the judge’s bench. “I’ll do my best to answer them.”
“I spent a lot of time looking through some of the photographs that were included in the Reticulum. Naturally, many of them were unrecognizable to me. I was very grateful for the automatic captioning; otherwise, in most cases, I’d have had no clue what I was looking at. But there were some photos that were startlingly familiar. Both your people and mine seem to have a fondness for sunsets.”
“Sunsets are beautiful.”
“Indeed they are. And both your sun and ours are very similar, what we call class-G yellow dwarfs. In fact, I’d have a hard time telling in a lot of cases whether a picture was of one of your sunsets or one of ours.”
Ursula’s eyestalks rippled in agreement. “I imagine it could be difficult.”
“But, of course, after the sun finally sets, things are different. Your system is forty-six light-years away from ours.”
“Forty-six of your light-years,” said Ursula amiably. “One hundred and two of ours.”
“Right, right. But, no matter which way you reckon it, it’s enough to shift the arrangement of stars. I’m not an astronomer, like Dr. Plaxton over there, but, if I understand correctly, the brightest star in our nighttime sky is the one we call Sirius, whereas in your sky, it’s the one we know as Canopus.”
“Yes, that’s true.”
“Of course, here, the moon outshines any star at night, especially when it’s full.”
“True.”
“And I suppose the same thing happens on your world.”
“No, it doesn’t.”
Sudeyko stopped his pacing as if startled. “Why not?”
“My world has no moon.”
“Really?” said Sudeyko, raising his eyebrows dramatically. “But then how do you know what a moon is?”
“There are two gas-giant planets in our system; each has several moons that we can observe through telescopes.”
“Ah, I see,” said Sudeyko. “And these gas giants—do they show visible disks to your unaided eyes, or are they just pinpoints of light like the stars?”
“The latter—though of course they move from night to night against the stellar background.”
“And, just to be clear, your world is a rocky planet, like ours?”
“More or less. It’s a little larger, and about two billion of your years older.”
Sudeyko waved those irrelevancies away. “Fine. But, again, to be clear, it’s not, in itself, a moon; that is, the object it orbits around is your sun, not a larger world.”
“That’s right.”
“I imagine on a clear night that you can see what we call the Milky Way, the band of stars visible when you look in toward the galactic center.”
“Yes. We call it the ‘Sky River.’ ”
“And perhaps, if you’re at the right place on your planet, you can even see our two satellite galaxies—the ones we call the Clouds of Magellan—or the tiny smudge of the nearest separate galaxy, Andromeda.”
“If one’s eyesight is normal, yes.”
“But there are no solid objects—nothing that shows as a disk; nothing that shows visible surface features—in your night sky, correct?”
“That’s right.”
Sudeyko seemed to consider for a time, but of course he was simply letting the impact of this register on the jurors. “Huh,” he said at last. “And, before the recess, Dr. Emily Chiu told us there are no seas or oceans on your world. So, perhaps you could tell me a bit about your previous experience with first contact.”
“I don’t know what you mean by that.”
Someone had stolen Emily’s seat during the recess; she was now four rows from the front. She shifted uncomfortably: Ursula was giving the correct answer, but Emily was afraid the journalists would misinterpret it as a failure on the software’s part.
“Oh,” said Sudeyko, as if a great mystery had been solved. “Right. Your planet is all one big land mass. So, there are no populations that were geographically isolated for millennia, correct?”
“If I follow your meaning, yes, that is correct.”
“So you never underwent anything like, say, what happened here when Europeans came to the Americas, or to Australia. You never had the devastation, the disease, and the decimation of populations that we experienced time and again when formerly isolated cultures came into contact, especially when one was clearly technologically more advanced than the other?”
“Yes, that’s true.”
“Well,” said Sudeyko, “the past’s the past. Let’s turn to the present. Tell me about your space program.”
“Pardon me?”
“You know: your astronauts, your spaceships.�
��
“I don’t know the words ‘astronauts’ or ‘spaceships.’ ”
“So you don’t have a space program?”
“Apparently not.”
“Why not? Judging by the material in the Reticulum, your civilization is substantially more advanced than ours, and we’ve been putting people in space for almost seventy years now.”
“It never occurred to us that such a thing was possible.”
“You didn’t dream from ancient times about going to other worlds?”
Ursula twirled her inside arm in baffled negation. “No. Why would we?”
“Well, that’s an interesting question,” said Sudeyko. “I suppose it’s possible that if we didn’t have a large moon ourselves—if we didn’t have another world hanging over our heads since the dawn of time, tantalizingly just out of reach—perhaps we wouldn’t have been inspired to venture into space, either.”
“That’s an interesting supposition,” agreed Ursula.
“You said earlier that an overwhelming majority of your whole population voted to send the Reticulum to planets in other star systems.”
“Yes.”
“Which means presumably most of you considered it a safe thing to do.”
“Of course.”
“Because, after all, if it never occurred to your people to travel even within your own solar system, it presumably never occurred to you that beings in other star systems might physically bridge the gulf between their world and yours.”
“What a novel suggestion! Yes, you’re right: That never occurred to us.”
Sudeyko moved over and began pacing back and forth in front of the jury box. It was hard to get anyone to take their eyes off Ursula in all her surrealist glory, but the historian wanted to be sure that everyone was looking at him, so his point would land with maximum force. “And so,” he said, “when your people voted, they were not considering the possibility that beings from another world, or their automated probes, might come and enslave, plunder, or destroy your world, isn’t that so?”
