“I sat there for a while, then I said to myself, Teri’s brighter than you. Why don’t you go and bounce it off her? And here I am.”
“Did you apply Lund’s First Rule of Oddities?”
Arabella Lund had been full of “rules,” and one of her most basic was this: Anything in the universe can happen once, or at least it can seem to happen. If you want to obtain information, make it happen again.
Torran nodded. “I did the same thing, three times over. I found identical results: send a signal, and microseconds afterwards we get a funny squiggle of radio sound on our receivers.”
“How did you send your message? I mean, was it in some particular direction?”
“No, I used omni-directional. Hell, if there was help to be had anywhere I wanted to hear from them. What is it, Teri? You’ve got an idea, haven’t you?”
“If you can call it that. It may be half-baked, but I want to try something. Let’s head back to the control room.”
“Do we need Julian Graves?”
Teri gave him a drop-dead-right-now glare. “You didn’t want to seem like an idiot in front of Julian Graves, but you don’t mind me doing it?”
“Sorry. What are you planning?”
“Wait and see. You didn’t tell me in advance.” Teri led the way to the control room. Once there, she ignored the radio wavelength equipment and went across the optical section. “Which one of these lasers provides the best collimated beam?”
“The blue-green. It diverges only one percent in fifty kilometers.”
“I hope that will be tight enough. How many microseconds after you started to send your call for help did the receivers begin to record radio noise, and how long after you stopped sending did the noise you received end?”
“I’ll have to check. It was small enough that only the instruments could pick it up—so far as I was concerned, they seemed simultaneous.” Torran moved across to the receiver displays. “Ninety-four microseconds, plus a fraction, for the delay at the beginning. And the signal went on for a hundred and sixty microseconds after my call ended.”
“That’s close enough.” Teri was at the laser station. “I’m going to send a one-second pulse from the blue-green laser. Watch the display. See anything?”
“Yes. A faint green dot showed on the screen—and it lasted about a second.”
“We’ll find when we measure it that it lasted exactly one second. Now I’m going to work my way around the full sphere, using one-second pulses every five degrees of arc. We’ll measure the exact time of return, and then we will know where we are—or at least, we’ll know the distance to the boundary.”
“What boundary?”
“Don’t you get it, Torran? We’re not in limbo, or in the Croquemort Timewell, or a spacetime hiatus. The ship is sitting inside some other object, with an interior surface that screens out external radiation and reflects interior radiation. The reason that you got what looked like random returns from your signal is because it went out in all directions, and the distance is not constant to all parts of the boundary wall. So the return was scrambled, with bits of your message jumbled together. It took ninety-four microseconds round-trip time to the nearest point on the boundary, and a hundred and sixty microseconds to the farthest point.
“Now, I’m going to assume that the velocity of propagating radiation is the same here as in open space—that seems pretty reasonable. So at three hundred thousand kilometers a second, we are fourteen kilometers away from the nearest point of the boundary, and twenty-four kilometers from the farthest point. I also find a zero Doppler shift in frequency between the outgoing laser pulses and their returns, so our ship is at rest relative to the boundary. The advantage of using laser pulses in precise directions is that we—or rather, the ship’s computer—can calculate and reconstruct the shape of the space we are inside, and also our ship’s distance from any point of the boundary. If we find places where the structure of the wall seems different, those are the logical spots where we should look for a way out.”
“Teri, you’re a marvel. Can we start that work at once?”
“I’d like to. But I think we ought to tell Julian Graves what we have learned. Do you know where he is?”
“Last time I saw him he was in his own cabin. Contemplating his navel, from the look of him. But you are right, he does need to be told. Come on.”
Julian Graves was in his own cabin. He was not actually contemplating his navel, but he was engaged in a pursuit that seemed just as unproductive. He sat in a chair, lightly strapped in position so that he would not move around in the ship’s free-fall environment. He was staring intently at a fixed point in space. Torran and Teri finally realized that a tiny green marble hung there, about a meter in front of Graves’s face.
Teri said, “Councilor, we have important news. We are not in limbo, or in some form of spacetime hiatus.”
Graves nodded. “I know. In a few minutes I was proposing to come and tell the two of you the same thing.”
Torran said, “But how could you possibly know that? You have been sitting in your cabin, and there are no instruments here.”
“Oh, but there are. The human eye and the human brain are both instruments, potentially of a high order. It is true that at no point have I looked beyond the ship itself, but I did not need to. I noticed an oddity in the control cabin some time ago. The ship’s drive appeared to be off, since we felt no accelerations. However, the drive monitors indicated that the drive was—and is—turned on, although at an extremely low level. Since our position sensors insist that we are at rest in inertial space, the only explanation is that the ship itself resides in a field of force, albeit a very weak one—far too weak to be apprehensible to human senses. If that is the case, then although the drive holds the ship itself in a fixed position, objects within the ship that are free to move should do so. They experience a small body force.”
Graves leaned back in his chair and placed his fingertips together. “You know, sitting here it occurs to me that maybe the worst mistake we have made on this whole expedition has been to assume that processes in the Sag Arm resemble in any way the familiar ones of our own Orion Arm. There are Builder artifacts here, and none is in any way like those with which we have experience. To paraphrase an old philosophical thought, the Sag Arm is not only more strange than we imagine; it is more strange than we can imagine.”
Torran’s glance at Teri sent a clear message: He’s gone gaga. The councilor is off his head. He said to Graves, “The human eye and brain may be instruments, but there is nothing here for them to look at and work on.”
“Oh, but there is.” Graves pointed to the green pill-sized ball hanging before him. “We are not in free-fall, you see, even though our bodies feel as though they are. We are not even in the microgravity environment provided by the gravity forces of the ship itself. Steven calculated and compensated for those. An external gravitational force is acting on everything in this ship. A minute one, to be sure, which is why we can’t feel it. But if you observe the green sphere, you will find that it is being accelerated very slowly away from me and toward the rear bulkhead. There is a slight asymmetry, a preferred direction to this environment. I can estimate its magnitude by observation of the little marble. However, I have no explanation as to its origin.”