“And what does this mean?”
“I don’t know, Adam. It must have meant something to the builders of the transmitter.”
Now Eve moves from sphere to sphere. She measures each of the distances again using the laser rangefinder from her tool belt. “Marchenko,” she says, "did you notice all these progressions converge on a natural number?”
I calculate the limits of the three progressions. And indeed they all are fixed values, rather than infinity. That is a strange coincidence. Why didn’t I notice this earlier? “Correct,” I confirm. “But does this mean something?”
On the camera image I see Eve shrug her shoulders.
“It is probably due to the fact that mathematics is universal,” I say. “One plus one is always two, on any planet and in any language.”
“Too bad,” Eve says. “I was hoping we had discovered some kind of code.”
“Or at least identified its purpose,” Adam adds.
“Concerning its purpose, we might have a chance to find that out. Please describe the material of the sphere, as well as that of the central mast.”
“One second. I have an analyzer,” Adam says as he reaches into his tool bag and pulls out a device that looks like a stubby pistol. The device bombards an object in as many wavelengths as possible and uses the reflected radiation to find out what it is made of. Adam starts with the sphere he is still holding on to. He pushes a few buttons, mumbles something incomprehensible, and then swims down to the transmitter dish. After repeating the procedure he compares the data.
“Ceramic,” he says, “so our first impression concerning porcelain wasn’t far off.”
“What are its components?” I ask.
“Just a sec, I am going to send you the data.”
The analysis appears in my memory unit. “Magnesium, calcium, titanium, cobalt,” I read out loud. “What does that remind you of?”
“Could be some high-temperature superconductor,” Adam says.
“Perhaps,” I reply, “but unfortunately we only get integrated values instead of an exact structural analysis. There might be several layers of different materials, or a thick layer in which all of these components occur. Those would lead to two completely different scenarios.”
“Couldn’t we find out more inside the station?” Eve asks. “Messenger had a scanning tunneling microscope.”
“There is probably something like that in the station, Eve, but for that purpose we would need to extract some material and take it with us.”
“Should I break something off?” Adam asks, acting as if he were about to hammer the analyzer against the edge of the dish.
“Don’t you dare!” I warn him, though I know he couldn’t be that irrational.
“The sensor is much too pretty to do that,” Eve says. “And what kind of impression would we make if we come here from far away and start smashing their china?”
“Never mind,” Adam says. He pushes himself off again and swims toward the central mast.
Oh yes, I think, we haven’t examined it closely yet.
Adam stretches out his arms in front of him. I am watching him through the camera. He is just about to grab the mast when his hand is suddenly stopped. Adam tries it a second time, but once more he can’t get closer than arm’s length.
“What is going on?” he yells, and turns toward the Valkyrie as if I could give him an explanation. Eve now also moves toward the mast. Does she think Adam is playing another trick on us? But she is also unable to touch the mast.
“Remember the infrared images?” I ask.
“I’ve been thinking of that,” Eve says. “The thermal conduction insulation is probably located inside this layer. But what exactly does it contain, and why is it invisible?”
“Adam, why don’t you try...” I don’t even have to finish the sentence. Adam takes the analyzer and aims it at the mast underneath the boundary layer. Silence reigns for several seconds. Time seems to stretch on. The device takes much longer than usual for its task. Adam stares intently at its display, though I know there won’t be anything to see there except for the message, ‘Please wait.’
“The numbers are puzzling,” Adam says after precisely one minute and 37 seconds.
“How puzzling?”
“I am sending them to you.” He pushes a button.
Now I see the data. Adam has not exaggerated. “The numbers really are baffling,” I say in agreement.
“In what way? Don’t leave me hanging here,” Eve says.
“The analyzer found nothing,” I say.
“Nothing? But there certainly is something there. You can see it, and it affects the thermal conduction, doesn’t it?” asks Eve.
“The device functions by examining reflected radiation at different wavelengths. But it didn’t find any. Either the radiation is completely absorbed by the material around the mast, or it is passed through just as completely,” I surmise.
“The first case is highly improbable,” Eve says. “Otherwise we wouldn’t have been able to detect the heat signature of the transmitter so clearly from far away. So the material must let anything coming from the inside pass through.”
“Correct,” I say in agreement. “It is much more likely that any radiation can pass through. We can test this with an experiment. Adam, set the analyzer to the maximum level and repeat the analysis.”
“What good will that do?” he asks.
“If all radiation truly goes through the material, it would hit normal materials behind it and be partially reflected by them. This should appear as a background signal in the analysis. We need maximum performance for this. Otherwise the signal would stay below the detection threshold. Normally, the analyzer is not supposed to measure the environment as well.”
“Okay.” Adam holds the analyzer gun as close to the mast as possible. We wait. This time, the procedure finishes faster. The device might have interpreted the background reflections as a measurement signal. Adam looks at what is happening on the display.
“Your theory is correct, Marchenko,” he says. “Water, silicon dioxide, various salts, exactly what one would expect of an ocean.” He presses the send button again. “So we know the stuff in there does not shield from radiation. Not one bit. Therefore it could only be a vacuum, or something close to it, right?”
Eve pushes off and swims upward along the mast, her arms outstretched so she can feel the invisible boundary. She reaches the top.
“The cover reaches all the way up here and is closed at the tip,” she reports via radio.
“I don’t understand,” Adam says. “That doesn’t make any sense! A transmitter that does not send, but uses energy? That’s totally inefficient! Why should somebody construct something like that, and even build it to last an eternity?”
It can’t be denied that the transmitter consumes energy, because it must somehow receive the heat it then radiates. Where does it come from? That is another question for which we do not yet have an answer.
“Perhaps it is not a transmitter, but rather a receiver that needs energy while waiting for a signal?”
Eve’s idea cannot be easily dismissed. A switched-on radio uses electricity, even during times when no programming can be heard. “And the spheres?” I ask.
“Perhaps they serve to adjust the frequency. Like tensioning or pressing guitar strings.”
Maybe Eve is on to something here. I am not quite convinced, but I feel we are getting closer to an answer.
“You mean the spheres are like knobs on a radio receiver, adjusting it to a particular frequency?” Adam asks with a laugh. “That sounds so crazy it might actually turn out to be true. But who is supposed to turn them?”
“Maybe they are not meant to be changed. Then the receiver would be tuned to a fixed frequency, set to stay that way. That would explain why the spheres obediently return to their original positions,” Eve says as she slowly sinks down from the top of the mast.
“I think we are wrong concerning the type of receiver. We a
re thinking too much in terms of Earth.”
“What do you mean, Marchenko? I definitely don’t think in terms of Earth,” Adam says.
“I wanted to say we are thinking in categories like radio communication. What if this has nothing to do with radio waves? Perhaps not even electromagnetic waves, but something altogether different?”
“You are considering something like sound waves? Not a bad idea,” Eve says. “Sound waves are pressure waves within a medium. If I change the medium—meaning the water—by means of the spheres, that would be a kind of frequency modulation.”
“But sound waves don’t make sense, because the range is much too short. The antenna is obviously aimed upward. Sound waves would stop at the vacuum and not get past the atmosphere.”
“The direction of the antenna, Marchenko, that is an important clue. It doesn’t look like it can be changed, so during the orbit of Proxima b around its sun it can reach only certain targets,” Eve says.
Or be reached by certain targets, I think. I simulate the course of the planet around its central star. I know the position of the antenna, as it sits vertically to the round exterior of the planet. Which planets or stars could it possibly send a signal to or receive one from, at least once a year? My program routines take a while to go through the entire star catalog. Finally, I get a result.
“Alpha Centauri,” I say.
“The neighboring star?” Adam asks.
“Yes, what else?” Eve says. “It is obvious it had to be something nearby. Perhaps that is the star they escaped to?”
“I don’t know... It could just be a coincidence,” I say.
“It certainly is,” Adam says. “Just take a look at the dimensions of the antenna. It has a diameter of just under 16 meters, and is even under water. That would never be sufficient to reach Alpha Centauri with a clear signal that could be distinguished from background noise.”
“You are thinking of a transmitter again,” Eve retorts. “A receiver could be much smaller, if the transmission power on the other side is large enough.”
“I still don’t believe we are dealing with a rather undersized radio receiver here,” I say.
“Could we check your theory?” Eve asks.
I think about this question. Whatever material the mast is made of, its outer skin exists in our world and therefore must obey our laws of physics. Seismographs explore the interior structure of the world by sending vibrations—in their case, soundwaves—downward and receiving the reflected signals. This should also work with the mast. We only have to strike it like a bell on top. Then the vibrations would propagate along its length and spread out. A large part would be absorbed, but some should return. Those signals will tell me everything about the mast.
“Okay, then let’s play ‘The Hunchback of Proxima b,’” I say.
Adam and Eve stare toward the Valkyrie, obviously confused. I don’t feel like explaining this to them. If it works, I can add the explanation later. After all, the two of them don’t explain all their ideas to me.
Valkyrie is not equipped with sonar, as a submarine would be. But a loudspeaker or microphone could fulfill the same function. The helmets of Adam and Eve contain sensitive microphones that can also receive sound from the outside. I would simply have to precisely log the vibrations caused by the measurement signal. I can get these data live thanks to the suit telemetry.
“Could you two swim up to the tip of the mast and hit it with some object?” I ask.
Adam follows my request, but asks in a puzzled voice: “Can I use anything, no matter what?”
“Yes, it’s your choice.”
Eve conspicuously shakes her head so that I can see it even through the helmet visor, but she doesn’t say anything. She swims upward with deliberate slowness and pulls a tool from her front suit pouch.
“You can start whenever you are ready,” I say.
The monitoring system of the suits will automatically record the two of them hitting the mast, along with the resulting sound waves. In the meantime I am preparing some algorithms to automatically extract the data relevant for me. The measurement method might be primitive, but I am not aiming for high precision. I just want to know one thing: Does the mast end shortly below the ocean floor, or does it reach far down?
I take a look through the cameras. Both of them are having fun. Hammering something in a seemingly-meaningless fashion seems really enjoyable. In a way it looks odd, as they are not really hitting the mast, but instead are striking the invisible barrier around it. Also, the water slows their arm swing so they are unable to hit with their full strength.
“But watch out. You’d better stop if you get the feeling something is about to break.”
“Certainly, boss,” Adam replies.
After five minutes I have enough measurement data to get a meaningful result. “You can stop now,” I say.
“So what was this supposed to do?” asks Eve, who is slowly swimming toward Valkyrie.
“Just a moment, I am running some calculations.”
“Don’t keep us in suspense,” she says.
“Let’s get back inside already,” Adam says with a bored voice. “I don’t believe we can find out anything else here.”
I hope to show them soon that the opposite is true. I nod my head until I remember that nobody can see this, because I currently have no head. “Yes, why don’t you come back inside? As soon as I have the results, we are traveling back to the station.”
The answer appears in my consciousness. It is an impressive feeling having the results of extensive calculations suddenly materialize inside my mind. When I was still a human being I occasionally caught a glimpse of this when a sudden inspiration made me slap my forehead with my hand. How could I have overlooked this obvious fact until now? I would think. I have a similar reaction to the result of the soundwave measurement. The insight appears out of the blue, right in the part of my consciousness that is actively dealing with this strange transmitter or receiver. Something—and I know that it is the algorithms running in my subconscious—drops it down. And then knowledge opens, as though previously hidden in a box, and it feels as though it should have always been here.
“People, the mast reaches down several kilometers,” I say.
Adam and Eve have already closed the hatch and are waiting for the water to drain. That’s perhaps why they don’t appreciate my insight the way I had hoped they would. Or perhaps I have to give them some background information.
“This makes it clear what kind of receiver we’ve got here.”
“Oh, really?” Eve says, sounding as if she is not truly interested in an explanation.
“It is a gravitational wave receiver. It is meant for...”
“... receiving gravitational waves, sure,” Adam interrupts me. “I already thought something like that.”
“Is that so?” I reply.
“Yes, really. It was somehow logical, so far under the sea. The device won’t be disturbed here.”
“But you didn’t say a word.”
“Well, I didn’t want to spoil your fun.”
No matter. I shouldn’t get upset now. If this is a gravitational wave receiver, this means there must be a transmitter somewhere. And that technology would not just be able to generate gravitational waves, but also to modulate them. This is far beyond mankind’s current abilities. Learning how to do this would provide an enormous advance for us.
“If this is a receiver, then where is the transmitter?” Eve asks as if reading my thoughts.
“Alpha Centauri?” Adam suggests.
“No, Adam, the position of the antenna then makes no real sense for gravitational waves,” I say. “Those can be detected more efficiently if they arrive parallel to one of the arms.”
“To one of the arms, precisely. Perhaps what we see here,” Adam says, pointing at the screen he just switched on, “is the arm of the sensor providing the control signal. The gravitational wave changes the lengths of the two arms, which are perpendicular to eac
h other, differently. This allows the actual signal to be detected.”
“You don’t have to explain the principle of a gravity wave detector to me,” I say. My voice sounds angrier than I intended.
“You would have done it, too, in his place,” Eve says.
I have to laugh. Eve is not completely wrong. “Well, you two smart alecks,” I say, “then what about the spheres? What is their function? Do they serve just as decoration?”
“Each mass influences the spread of gravitational waves. Thus they could function as a kind of tuner,” Adam says.
“They are much too light for that. Gravitational waves are created through the interaction between black holes or neutron stars, not by a few spheres with a diameter of one meter.”
Of course I know this is not exactly true, but only limited by our measurement precision. The gravitational waves generated by a collision of the spheres would be minimal and impossible to measure, even for a technologically-advanced civilization.
“How do you know their weight?” Adam asks.
“That’s not hard to estimate. The volume of the sphere multiplied by the density of the heaviest known material...”
“And what if the contents of the spheres are an unknown material?”
“That is pure speculation, Adam.”
“Everything we do here is a wild guess, so why shouldn’t we engage in some reasoned speculation? What if the spheres contain dark matter? The lambda-cold dark matter model assumes that its particles would have to be very dense and heavy.”
“But we haven’t measured anything.”
“Exactly,” Adam says. “Dark matter would not interact with electromagnetic radiation. That’s why we can’t see it.”
“I know all that,” I say, “but so far, all that is only a theory. Nobody knows what dark matter is made of. We are only pretty sure that it must exist.”
“My thoughts exactly!” Adam replies.
“So how would the builders of this device have collected dark matter?”
Proxima Trilogy: Part 1-3: Hard Science Fiction Page 28