Tomorrow and Tomorrow

enough to use S-wave signaling. How would it affect our ability to send a signal to them?”

“To send a signal? That would be very easy. Our S-wave detector can transmit as accurately and rapidly as it receives. That would not seem to be the issue here. The question is, What will happen to our signal when it is received in the other galaxy?”

“That’s going to be my problem, isn’t it?” Drake saw no point in talking generalities any longer. “Once I’m back in electronic storage, how long will it take to transmit me superluminally?”

“A few hours at the most. ”

“Then let’s do it. You said eight hundred million light-years?”

“Eight hundred and eighteen million, to be more precise. ”

“How much travel time is that for you — allowing for fuel and maintenance and everything else?”

“Most would have to be in coast phase, since between the galaxies there are no ready sources of materials or energy. Necessarily, that would imply long periods of low or zero acceleration. The travel time would be a billion years or more.”

“You can survive that?”

“Of course. Already we have endured tens of times that interval. However, I must mention two other anomalous features of the received signals. First, although there are many signals, million after million of them, they clearly fall into two different types.”

“How do you know that, if you can’t understand what they say?”

“By statistical analysis of the bit streams. That analysis clearly reveals two distinct types, although the content of either type remains unknown. And that is the second anomaly. In principle, my analytical tools should permit the interpretation of any possible signal whatsoever. It makes no difference if the sender is human or nonhuman, organic or inorganic, familiar or utterly alien. If the laws of logic, which we have always believed to be universal, are being followed, the signal should be intelligible.”

“But these are not? Very curious. Chances are it will be easier to sort out what’s going on when we’re there to see it.” But Drake was expressing a confidence that he did not feel. He sensed old memories stirring within him. Two kinds of signal that clearly were signals, but neither of which could be interpreted. Why did that sound familiar?

“First, switch me back to electronic storage. Then send me on my way. After I’m gone, you can take the slow road and join me.” Signals that could not be understood. Algorithms that should be able to interpret anything, but failed to do so. He postponed the question. He would have time to consider it when he reached the signal source. “Let’s get me to electronic form, so I can go to work. Assuming that things work out all right, I’ll beam myself back here and tell you what’s going on.”

Assuming that things work out all right.

It occurred to Drake, rising to consciousness, that nothing had gone right for aeons. They had certainly not gone right this time. Rather than waking in some other galaxy, delivered as an S-wave and reconstructed to consciousness, he was still on board the ship. And although he was awake, he was certainly not embodied. Instead he was in electronic form, sharing sensors and processors with the ship. He was also aware of the hundred or more other versions of himself, dormant around him.

“All right. It didn’t work. What’s happening now?”

Part of the answer came to him even before the ship spoke. The visible light sensors revealed face-on the disk of a barred galaxy. From the way that it filled the sky ahead, they were within a few tens of thousands of light-years — touching distance, in intergalactic terms.

Also, it was the galaxy. The ship’s signal-receiving equipment showed the spiral arms filled with the glittering sparks of S-wave transmissions. The galaxy flamed with them, bright flickering points of blue and crimson. They had been color coded by the ship into type 1 and type 2 — statistically different from each other, but equally mysterious.

If the ship was here, so close to the source of the signals, then a billion years or more must have passed since he was last conscious.

Why wasn’t the ship answering his question? And then Drake realized that the ship had answered. A new block of information had been transferred, and his electronic consciousness was already processing it, thousands or millions of times faster than his old organic one. He knew, without being told…

The ship had remained for centuries at the focal point of the giant array. It had transmitted Drake as a superluminal

signal — not once but a hundred times and more. It had waited patiently for a return signal. Nothing came into the array but the same endless stream of unintelligible communications.

At last the ship had to make a difficult choice. If it left the array, all chance of receiving an intergalactic signal from Drake was lost. The ship would be forced to rely again on the simple S-wave detection system that it carried on board. On the other hand, to remain in one place and wait for a signal from Drake might take until the end of the universe.

Finally the ship abandoned the array and set out on its lonely billion-year journey across the intergalactic gulf. In doing so, it lost the ability to pick up superluminal signals from its destination until the target galaxy was close enough for the on-board system to operate.

How close?

This close. Close enough for the ship to employ a synthetic aperture optical system, able to produce visible wavelength pictures of surface detail on planets the size of Earth.

And now a new problem arose. It was baffling enough for the ship to know that it needed help. It had brought Drake to consciousness.

And because he would need direct access to all sensor inputs, and because in any case there was no planet within twenty thousand light-years where an embodied organic form might prove useful, the ship employed a different procedure. It did not embody the aroused intelligence, but resurrected it in electronic form.

Drake examined one of the planetary images as the ship drifted steadily on through space. The world was superficially Earth-like, sufficiently massive and far enough from its primary to hold an atmosphere. It should have had air of some kind, nitrogen or methane or carbon dioxide or, if it bore life, oxygen and water vapor. No trace of any showed up in the gas spectral analysis. The surface, unobscured by clouds or a shroud of air, was black rock. It looked like volcanic basalt that had flowed under high temperature before pooling and hardening to grotesque formations. There was no sign of surface water, no sign of life or surface artifacts. Orbiting the world like a swarm of lightning bugs were hundreds of objects too small to be seen with the imagers. However, from time to time a flash from one of them showed that it was transmitting, and the ship was receiving, an outgoing S-wave signal.

What was there to talk about in facilities that orbited long-dead worlds?

Drake tracked the destinations of the outgoing data bursts, and the ship offered their images at his command: world after world, scene after scene of charred devastation. Every planet was in ruins. Each was clearly lifeless.

“I have performed as complete a survey as possible from this distance.” The ship’s messages were clear and easy now that Drake knew how to listen to them. “The pattern repeats from one side of the galaxy to the other, from the outer rim to the central disk. Those worlds have in common what I have termed a type one superluminal message capability. Compare them with the type two worlds.”

Another sequence of planets was offered for Drake’s inspection. From the ship’s point of view, there were large differences. From a human point of view, one similarity overwhelmed every other factor: organic life was absent.

Drake examined a thousand type 2 planets where everything that humans had learned of physics, planetology, and biology suggested that life should have developed. The sun was an appropriate spectral type, surface temperature was in the right range, the planet had a low-eccentricity orbit, there was plenty of surface water, and a thick atmosphere of hydrogen, carbon dioxide, and nitrogen.

Life should have developed — must have developed. And it had developed. The proof was in the swarm of active devices around each world, emitting