Roger Allen - The Ring of Charon

The image blanked, and then the sphere reappeared, unbroken and whole. “The sequence loops at that point,” Marcia said. “It was repeated at least a hundred times, far more often than any other message unit. That suggests to me that whatever that showed us was damned important to the Charonians.”

“To the who?” Larry asked.

Marcia shrugged. “The aliens. I had to name them something. The Ring of Charon was what woke them up, so Charonians seemed as good as anything.”

“Where did these images come from?” Raphael asked.

“From the wormhole,” Marcia replied. “It was sent, as a binary-code signal, by whatever is on the other side of the wormhole. And I’m sorry, Hiram, but I’m convinced that’s what the Earthpoint mass is. I don’t know who or what on this end is supposed to see it.”

“How was it sent?” Lucian asked.

“Forty-two-centimeter radio signals, sent in burst patterns. Answering the twenty-one-centimeter signal coming from the Moon.”

“How could radio pass through a wormhole?” Lucian asked.

“Mostly because there’s nothing to stop it, as I understand it,” Marcia said. “A wormhole isn’t as much a hole as a door, a way of putting two planes of normal space next to each other. Once that door’s open, anything that can pass through normal space—matter, energy, radiation, whatever—can cross the wormhole.”

“Hell’s bells, if you can drop planets through the hole, what’s a few lousy radio waves?” someone asked.

Radio waves . An idea suddenly started tickling at the base of Larry’s mind, but the conversation steamrollered on, and he lost his train of thought.

McGillicutty stood up and leaned in toward the hologram to get a better look. The grim red of the sphere made his face into something forbidding and sepulchral. “I knew you were working on cracking their signals, Marcia, but I had no idea you had gotten so far. You should have come to me for help. With imagery this complex, you had to make some choices and interpretations you’re not trained to make. How solid is this? I mean, how reliable could this be?”

“It’s close, very, very close to what was sent,” Marcia replied in a steely voice. “I’d say the colors, for example, are within angstroms of the intended value. Aside from bringing the latitude and longitude lines up when you asked, I haven’t enhanced or manipulated it at all. Time scale and physical scale, I have no idea on. This could be a record of a beach-ball-sized object popping— or a planet or a star being wrecked. All I know is it seems to be important to the Charonians.”

“What in God’s name is it?” Raphael asked in the darkness.

The room was silent for a long time. “This is a damn sophisticated four-dee image,” McGillicutty said at last, in a voice that seemed to be louder than it had to be. “How the hell did you manage to crack it?”

Marcia laughed, a low, throaty chuckle that came from the darkness, and a gleaming flicker of teeth flashed. “I told you I thought it would make sense to start at the end,” Marcia said. “I wanted to show you that I really had something before I explained how I got it. I know it seems amazing that I could come up with images and data so fast—even more so when I have no idea what the data mean. I wish I could take credit for cracking the enemy’s codes—but I can’t. These messages were designed to be decoded.

“In fact that’s the thing that worries me the most. Your invaders, Dr. Raphael, have done worse than deliberately ignore us. I get the distinct impression that it has never even occurred to them that we might be a threat, or even an issue. I think it would be a major effort of will for them even to realize we exist. They send messages back and forth right in front of us, the way we might talk about taking the dog to the vet while he’s in the room. We assume dogs can’t possibly understand people, and maybe they assume people can’t possibly understand Charonians. Maybe they’re right. I don’t know what they’re saying.”

Again, awkward silence blanketed the room. This time McGillicutty’s grating voice was almost a relief. “Dammit, MacDougal, how the hell did you unbutton this message?” He wasn’t going to let that question go.

“Arecibo technique,” Marcia replied. “A big old radio telescope they used in the twentieth century. On Bermuda or Cuba or someplace. It’s an old, old idea. The idea was to send out a binary message based on simple enough concepts and images that a totally alien culture could understand it. Something you could plot to graph paper—fill in a square for a binary on , leave it blank for a binary off to form pictures.

“A lot of your first message would consist of basic concepts of number, size, atomic structure in schematic form, that sort of thing. Count from one to, say, ten, then run the beginning of the prime-number series, maybe demonstrate the Pythagorean theorem by drawing a right triangle. Once you’ve sent enough for them to get the idea, maybe you send an outline sketch of what your species looks like, or a map of your planet or solar system. Your radio wavelength could provide a linear scale to give the size of any image you drew.

“The idea went that once you had a basic information set of number, geometry, scale, and atomic notation, you could move from there to real conversation, except that they were talking about signals sent to alien races light-years away.

“If you got good enough, and could establish a gray scale and a color scale, you could send detailed pictures. I don’t think anyone back then ever considered sending fully three-dimensional moving images, but the principle is the same. The first series of messages back and forth between the Moon and whatever the hell is on the other end of the wormhole closely resembled the number sequences I’ve just described.”

“Wait a second,” Larry objected. “This whole technique you’re describing is a means for sending messages to someone who doesn’t understand your language.”

“Right. In essence the first thing you do is send a grammar book to make sure they understand what follows.”

“But they’re sending messages to their own people,” Larry protested. “That’s nuts.”

“All I know is what I saw when I unbuttoned the message traffic. The computer was able to break it in real time into a two-dimensional grid. I had to walk the program through interpretation of the first outgoing message-grid—what the math examples were, what symbols they were using for numbers and atomic structures. Once the computer got the idea, it was off and running, learning the new language on its own. I just sat there and watched it. It was a classic example of the sort of grid messages we all dreamed up a million times in my xeno-bio classes—just more elaborate and sophisticated.

“You know about that twenty-one-centimeter signal coming from somewhere on the Moon. No one can find its source transmitter. That signal seems to go through to the Charonians on the other side. They send back a copy of the message at a doubled wavelength to signal receipt, and then send their own messages. Then the Lunar Charonian transmitter echoes the message from the other side. Once or twice the Lunar transmitter sends a perfect echo and then a slightly altered one. I didn’t get it until I compared the two copies. It was correcting the wormhole Charonian’s language errors.

“There’s no doubt in my mind on two points: That the Lunar Charonian had to teach whatever-it-was-sending-to the Lunar Charonian language. And that the receiving whatever-it-was was expecting a language lesson. It was too fast off the mark, replied too quickly. Which suggests the receiver had to be prepared to receive this message— even though they did not understand the language. It demonstrated that by making mistakes as it learned.”