“It’s true, Doctor. It’s already diverted the Polyphemus array. Now it apparently wants to try for a counterpart image at the visible wavelengths. But with optical-viewing time booked three months in advance, I thought I’d better—”
“Yes, yes. You did the right thing to call me.” The director’s eyes already were roving restlessly over the winking lights and flickering data screens of the big board. “What have you got so far?”
The tech turned on her lightpad. Her handwriting and underlinings, in scratches of blue lightning on the pad’s polycrystalline surface, crowded the computer-generated script she had dialed in from the board.
“Well, for one thing it doesn’t pulse. It just gives off a steady X-ray emission consistent with a point source.”
“Hmmm. How about the possibility of sinusoidal variation with a period of several hours, like Cyg X-3?”
She shook her head firmly. “The computer’s been tracking it long enough to have detected a curve. It’s a radio source, too. We have a fix on it with Polyphemus.”
Ruiz raised a shaggy eyebrow. “You diverted Polyphemus?
She stood her ground. “Yes, Doctor. I’m authorized to—”
“Don’t worry about it.” He laughed. “I’ll deal with Dr. Shevchenko. You’re doing fine so far. Go on.”
The junior resident butted in, trying to get himself noticed. “Excuse me, Dr. Ruiz, but the X-ray source is only a couple of seconds of arc from Cyg X-1. It confused the telescope at first. Doesn’t that suggest that it’s been occulted by X-1 until now?”
“And what do
The tech blushed. “It’s only twenty-eight days since the last sighting. Cyg X-1 is over ten thousand light-years away. The new source
“And what does
Maybury gave the junior resident an apologetic glance. “That it’s the other way around. The new source may have been masked by Cyg X-l, but it’s closer to the solar system.”
“My thought exactly.”
Ruiz walked over to the observation window, an imposing and dignified figure despite his baggy shorts, his knobby joints, the legs twisted by rickets that were his legacy from his childhood in New Manhattan. He looked out at the starry sky and located the Swan. He stared at it a long time, as if he were making up his mind about something.
With a casualness that made the other two gasp, Ruiz turned back to the board and punched in an authorization for the immediate use of the 500-inch Sagan mirror in the Tsiolkovsky crater. Diverting the giant telescope from high-priority projects wasn’t something you did lightly, even if you were the director of Farside Station.
Instantly, a stunning image sprang into life on the photoplastic viewplate. It was truer and richer than the images that had been possible on the obsolete photographic emulsions of the twentieth century. There was no graininess with enlargement. They were seeing, in real time, exactly what the big eye was seeing halfway across the Moon.
There was an illusion of stars swimming across the plate, as electrical potentials changed on the plastic’s surface. The stars halted as the Farside computer locked the telescope into the Polyphemus radio array.
The blue supergiant known as HDE 226868 was plainly visible as a bloated disk, thanks to computer enhancement of thousands of separate millisecond-long exposures. You could even see the pronounced bulge at one side, where its substance was being sucked away by its invisible companion—invisible because black holes swallow their own light, as they swallow everything else.
Ruiz made the computer generate a phantom image derived from radio waves and X-ray scatter. A fuzzy speck of cotton appeared opposite the tip of the bulge. He shifted focus and found another cotton ball halfway between Cyg X-1 and Deneb. Whatever the new source was, it wasn’t part of a binary. He frowned.
Maybury had been busy comparing her first entries on the lightpad with the updated figures on the board. “Dr. Ruiz,” she said in a puzzled tone, “there’s no proper motion that the computer can detect. I know the observational sample is still very small, but the new object seems to have stopped its lateral movement. She hesitated. “That would mean that it’s changed direction twice in the last twenty-eight days.”
The junior astronomy resident snorted. “That’s impossible!”
Nobody paid any attention. Ruiz looked thoughtful. “Mizz Maybury…”
She was way ahead of him. She scribbled a question on her lightpad and read off the answer that appeared a moment later.
“The computer says that both the radio waves and X-ray emissions are blue-shifted,” she said. “It’s been compensating for our benefit.”
“That means that the object is moving toward us,” the resident said brightly.
Ruiz switched off the ghost image and stared intently at the place where it had been. There was nothing visible.
But Deneb jiggled.
The others saw it too. All of a sudden the room was very quiet.
“Mizz, Maybury,” Ruiz said, “will you ask the computer to generate a star chart on this screen? Just the main reference points will do.”
“I’ll do it,” the junior resident offered.
A scattering of white crosses appeared on the screen, canceling out the stars. But Deneb was still there, displaced inward toward the cotton ball.
“It’s bending light, whatever it is,” Ruiz said. “And it’s between us and—”
Angry squawking from the wall communicator interrupted him. He looked up and saw the apoplectic face of Dr. Mackie, the chief astronomer at the Sagan dome.
“Dr. Ruiz!” Mackie sputtered. “I must protest the highhanded manner in which you preempted the schedule of the five-hundred-inch mirror. There are such things as review boards, and I can assure you that—”
“Calm down, Horace,” Ruiz said. “I think you’d better get over here right away.”
Mackie’s truculence faded suddenly. “What have you got?” he said carefully.
“I’m not sure, but I want you in on it. Requisition the courier rocket. If you leave right away, you can be here in an hour.”
As soon as Mackie switched off, Ruiz called Central Communications. “Put this through to the Mars station. Personal, direct to Dr. Larrabee at the Syrtis Major radio observatory. Wake him up if he’s asleep.”
“You’re on, Doctor,” Communications said.
Ruiz spoke rapidly and precisely into the communicator, giving coordinates, explaining the situation in as few words as possible. “…And, Larry,” he finished, “don’t waste time calling me back for a confirmation. Just do it.”
He switched off and settled back in one of the swivel chairs. “How about some coffee while we’re waiting?” he said.
The wait was over an hour. There could be no such thing as a conversation with Mars, particularly when Mars was on the other side of the Sun, as it was now. As the crow flies, it would take radio waves a bit more than twenty minutes to travel one way. But the crow would not fly through the sun. The message had to be bounced off the relay satellite orbiting Venus, currently a quarter orbit ahead of Earth, and in line of sight with both Earth and Mars. The round trip for an exchange of messages, with the detour, would take about an hour, even if Larrabee answered immediately.
He answered almost immediately. Ruiz was into his third cup of lukewarm coffee when Larrabee’s voice came out of the wall, clear as a bell, with all the interplanetary static edited out by the computer. Voice transmissions from Mars were sent in pulse-code modulation with triple redundancy, and in the unlikely event that any particular pulse was wiped out all three times, the gap was too infinitesimal for the human ear to detect.
“I don’t know what this is all about, Hernando,” a cheerful baritone said, “but I’ll take your word for it that it’s important. We’re zeroing in on your Cygnus source now. Just sit tight a couple more minutes. I’ll keep the beam open. You owe me a drink when I get back.”
Ruiz sipped another cup while the resident, Kerry, hovered around him and Maybury punched setups into the
