Lear had treasured the aloneness of those walks. But it was worse than that. Childrey had given him a list of possible escorts: half a dozen men Childrey could trust to see to it that Lear did nothing dangerous to himself or others. Inevitably they were the men most thoroughly trained in s.p.a.ce survival routines, most addicted to Childrey's own compulsive neatness, least likely to sympathize with Lear's way of living. Lear was as likely to ask Childrey himself to go walking with him.

He almost never went out any more. I knew exactly where to find him.

I stood beneath him, looking up through the gridwork floor.

He'd almost finished dismantling the protective panels around the gravity communicator. What showed inside looked like parts of a computer in one spot, electromagnetic coils in most places, and a square array of pushb.u.t.tons that might have been the aliens' idea of a typewriter. Lear was using a magnetic induction sensor to try to trace wiring without actually tearing off the insulation.

I called, "How you making out?"

"No good," he said. "The insulation seems to be one hundred per cent perfect. Now I'm afraid to open it up. No telling how much power is running through there, if it needs shielding that good." He smiled down at me. "Let me show you something."

"What?"

He flipped a toggle above a dull gray circular plate. "This thing is a microphone. It took me a while to find it. I am Andrew Lear, speaking to whoever may be listening." He switched it off, then ripped paper from the Ma.s.s Indicator and showed me squiggles interrupting smooth sine waves. "There. The sound of my voice in gravity radiation. It won't disappear until it's reached the edges of the universe."

"Lear, you mentioned quantum black holes there. What's a quantum black hole?"

"Um. You know what a black hole is."

"I ought to." Lear had educated us on the subject, at length, during the months aboard Lowell.

When a not too ma.s.sive star has used up its nuclear fuel, it collapses into a white dwarf. A heavier star-say, 1.44 times the ma.s.s of the sun and larger-can burn out its fuel, then collapse into itself until it is ten kilometers across and composed solely of neutrons packed edge to edge: the densest matter in this universe.

But a big star goes further than that. When a really ma.s.sive star runs its course when the radiation pressure within is no longer strong enough to hold the outer layers against the star's own ferocious gravity . . . then it can fall into itself entirely, until gravity is stronger than any other force, until it is compressed past the Schwarzchild radius and effectively leaves the universe. What happens to it then is problematical. The Schwarzchild radius is the boundary beyond which nothing can climb out of the gravity well, not even light.

The star is gone then, but the ma.s.s remains: a lightless hole in s.p.a.ce, perhaps a hole into another universe.

"A collapsing star can leave a black hole," said Lear. "There may be bigger black holes, whole galaxies that have fallen into themselves. But there's no other way a black hole can form, now."

"So?"

"There was a time when black holes of all sizes could form. That was during the Big Bang, the explosion that started the expanding universe. The forces in that blast could have compressed little local vortices of matter past the Schwarzchild radius. What that left behind-the smallest ones, anyway-we call quantum black holes."

I heard a distinctive laugh behind me as Captain Childrey walked into view. The bulk of the communicator would have hidden him from Lear, and I hadn't heard him come up. He called, "Just how big a thing are you talking about? Could I pick one up and throw it at you?"

"You'd disappear into one that size," Lear said seriously. "A black hole the ma.s.s of the Earth would only be a centimeter across. No, I'm talking about things from ten-to-the-minus-fifth grams on up. There could be one at the center of the sun-"

"Eek!"

Lear was trying. He didn't like being kidded, but he didn't know how to stop it. Keeping it serious wasn't the way, but he didn't know that either. "Say ten-to-the-seventeenth grams in ma.s.s and ten-to-the-minus-eleven centimeters across. It would be swallowing a few atoms a day."

"Well, at least you know where to find it," said Childrey. "Now all you have to do is go after it."

Lear nodded, still serious. "There could be quantum black holes in asteroids. A small asteroid could capture a quantum black hole easily enough, especially if it was charged; a black hole can hold a charge, you know-"

"Ri-ight."

"All we'd have to do is check out a small asteroid with the Ma.s.s Detector. If it ma.s.ses more than it should, we push it aside and see if it leaves a black hole behind."

"You'd need little teeny eyes to see something that small. Anyway, what would you do with it?"

"You put a charge on it, if it hasn't got one already, and electromagnetic fields. You can vibrate it to make gravity; then you manipulate it with radiation. I think I've got one in here," he said, patting the alien communicator.

"Ri-ight," said Childrey, and he went away laughing.

Within a week the whole base was referring to Lear as the Hole Man, the man with the black hole between his ears.

It hadn't sounded funny when Lear was telling me about it. The rich variety of the universe. . . But when Childrey talked about the black hole in Lear's Anything Box, it sounded hilarious.

Please note: Childrey did not misunderstand anything Lear had said. Childrey wasn't stupid. He merely thought Lear was crazy. He could not have gotten away with making fun of Lear, not among educated men, without knowing exactly what he was doing.

Meanwhile the work went on.

There were pools of Marsdust, fascinating stuff, fine enough to behave like viscous oil, and knee-deep. Wading through it wasn't dangerous, but it was very hard work, and we avoided it. One day Brace waded out into the nearest of the pools and started feeling around under the dust. Hunch, he said. He came up with some eroded plastic-like containers. The aliens had used the pool as a garbage dump.

We were having little luck with chemical a.n.a.lysis of the base materials. They were virtually indestructible. We learned more about the chemistry of the alien visitors themselves. They had left traces of themselves on the benches and on the communal waterbed. The traces had most of the chemical components of protoplasm, but Arsvey found no sign of DNA. Not surprising, he said, There must be other giant organic molecules suitable for gene coding.

The aliens had left volumes of notes behind. The script was a mystery, of course, but we studied the photographs and diagrams. A lot of them were notes on anthropology!

The aliens had been studying Earth during the first Ice Age.

None of us were anthropologists, and that was a d.a.m.n shame. We never learned if we'd found anything new. All we could do was photograph the stuff and beam it up to Lowell. One thing was sure: the aliens had left very long ago, and they had left the lighting and air systems running and the communicator sending a carrier wave.

For us? Who else?

The alternative was that the base had been switched off for some six hundred thousand years, then come back on when something detected Lowell approaching Mars. Lear didn't believe it. "If the power had been off in the communicator," he said, "the ma.s.s wouldn't be in there any more. The fields have to be going to hold it in place. It's smaller than an atom; it'd fall through anything solid."

So the base power system had been running for all that time. What the h.e.l.l could it be? And where? We traced some cables and found that it was under the base, under several yards of Marsdust fused to lava. We didn't try to dig through that.

The source was probably geophysical: a hole deep into the core of the planet. The aliens might have wanted to dig such a hole to take core samples. Afterward they would have set up a generator to use the temperature difference between the core and the surface.

Meanwhile, Lear spent some time tracing down the power sources in the communicator. He found a way to shut off the carrier wave. Now the ma.s.s, if there was a ma.s.s, was at rest in there. It was strange to see the Forward Ma.s.s Detector pouring out straight lines instead of drastically peaked sine waves.

We were ill-equipped to take advantage of these riches. We had been fitted out to explore Mars, not a bit of civilization from another star. Lear was the exception. He was in his element, with but one thing to mar his happiness.

I don't know what the final argument was about. I was engaged on another project. The Mars lander still had fuel in it. NASA had given us plenty of fuel to hover while we looked for a landing spot. After some heated discussion, we had agreed to take the vehicle up and hover it next to the nearby dust pool on low thrust.

It worked fine. The dust rose up in a great soft cloud and went away toward the horizon, leaving the pond bottom covered with otherworldly junk. And more! Arsvey started screaming at Brace to back off. Fortunately Brace kept his head. He tilted us over to one side and took us away on a gentle curve. The backblast never touched the skeletons.

We worked out there for hours, being very finicky indeed. Here was another skill none of us would own to, but we'd read about how careful an archaeologist has to be, and we did our best. Traces of water had had time to turn some of the dust to natural cement, so that some of the skeletons were fixed to the rock. But we got a couple free. We put them on stretchers and brought them back. One crumbled the instant the air came hissing into the lock. We left the other outside.

The aliens had not had the habit of taking baths. We'd set up a bathtub with very tall sides, in a room the aliens had reserved for some incomprehensible ritual. I had stripped off my pressure Suit and was heading for the bathtub, very tired, hoping that n.o.body would be in it.

I heard voices before I saw them.

Lear was shouting.

Childrey wasn't, but his voice was a carrying one. It carried mockery. He was standing between the supporting pillars. His hands were on his hips, his teeth gleamed white, his head was thrown back to look up at Lear.

He finished talking. For a time neither of them moved. Then Lear made a sound of disgust. He turned away and pushed one of the b.u.t.tons on what might have been an alien typewriter keyboard.

Childrey looked startled. He slapped at his right thigh and brought the hand away b.l.o.o.d.y. He stared at it, then looked up at Lear. He started to ask a question.

He crumpled slowly in the low gravity. I got to him before he hit the ground. I cut his pants open and tied a handkerchief over the blood spot. It was a small puncture, but the flesh was puckered above it on a line with his groin.

Childrey tried to speak. His eyes were wide. He coughed, and there was blood in his mouth.

I guess I froze. How could I help if I couldn't tell what had happened? I saw a blood spot on his right shoulder, and I tore the shirt open and found another tiny puncture wound.

The doctor arrived.

It took Childrey an hour to die, but the doctor had given up much earlier. Between the wound in his shoulder and the wound in his thigh, Childrey's flesh had been ruptured in a narrow line that ran through one lung and his stomach and part of his intestinal tract. The autopsy showed a tiny, very neat hole drilled through the hipbones.

We looked for, and found, a hole in the floor beneath the communicator. It was the size of a pencil lead, and packed with dust.

"I made a mistake," Lear told the rest of us at the inquest. "I should never have touched that particular b.u.t.ton. It must have switched off the fields that held the ma.s.s in place. It just dropped. Captain Childrey was underneath."

And it had gone straight through him, eating the ma.s.s of him as it went.

"No, not quite," said Lear. "I'd guessed it ma.s.sed about ten-to-the-fourteenth grams. That only makes it ten-to-the-minus-sixth Angstrom across, much smaller than an atom. It wouldn't have absorbed much. The damage was done to Childrey by tidal effects as it pa.s.sed through him. You saw how it pulverized the material of the floor."

Not surprisingly, the subject of murder did come up.

Lear shrugged it off. "Murder with what? Childrey didn't believe there was a black hole in there at all. Neither did many of you." He smiled suddenly. "Can you imagine what the trial would be like? Imagine the prosecuting attorney trying to tell a jury what he thinks happened. First he's got to tell them what a black hole is. Then a quantum black hole. Then he's got to explain why he doesn't have the murder weapon, and where he left it, freely falling through Mars! And if he gets that far without being laughed out of court, he's still got to explain how a thing smaller than an atom could hurt anyone!"

But didn't Dr. Lear know the thing was dangerous? Could he not have guessed its enormous ma.s.s from the way it behaved?

Lear spread his hands. "Gentlemen, we're dealing with more variables than just ma.s.s. Field strength, for instance. I might have guessed its ma.s.s from the force it took to keep it there, but did any of us expect the aliens to calibrate their dials in the metric system?"

Surely there must have been safeties to keep the fields from being shut off accidentally. Lear must have bypa.s.sed them.

"Yes, I probably did, accidentally. I did quite a lot of fiddling to find out how things worked."

It got dropped there. Obviously there would be no trial. No ordinary judge or jury could be expected to understand what the attorneys would be talking about. A couple of things never did get mentioned.

For instance: Childrey's last words. I might or might not have repeated them if I'd been asked to. They were: "All right, show me! Show it to me or admit it isn't there!"

As the court was breaking up I spoke to Lear with my voice lowered. "That was probably the most unique murder weapon in history."

He whispered, "If you said that in company I could sue for slander."

"Yeah? Really? Are you going to explain to a jury what you think I implied happened?"

"No, I'll let you get away with it this time."

"h.e.l.l, you didn't get away scot-free yourself. What are you going to study now?

The only known black hole in the universe, and you let it drop through your fingers."

Lear frowned. "You're right. Partly right, anyway. But I knew as much about it as I was going to, the way I was going. Now. . . I stopped it vibrating in there, then took the ma.s.s of the entire setup with the Forward Ma.s.s Sensor. Now the black hole isn't in there any more. I can get the ma.s.s of the black hole by taking the ma.s.s of the communicator alone."

"And I can cut the machine open, see what's inside. How they controlled it. d.a.m.n it, I wish I were six years old."

"What? Why?"

"Well. . . I don't have the times straightened out. The math is chancy. Either a few years from now, or a few centuries, there's going to be a black hole between Earth and Jupiter. It'll be big enough to study. I think about forty years."

When I realized what he was implying, I didn't know whether to laugh or scream. "Lear, you can't think that something that small could absorb Mars!"

"Well, remember that it absorbs everything it comes near. A nucleus here, an electron there . . . and it's not just waiting for atoms to fall into it. Its gravity is ferocious, and it's falling back and forth through the center of the planet, sweeping up matter. The more it eats, the bigger it gets, with its volume going up as the cube of the ma.s.s. Sooner or later, yes, it'll absorb Mars. By then it'll be just less than a millimeter across-big enough to see."

"Could it happen within thirteen months?"

"Before we leave? Hmm." Lear's eyes took on a faraway look. "I don't think so. I'll have to work it out. The math is chancy...

"Meet Ftaxanthir and Hroflhliss and Chorrikst. Chorrikst tells me she's nearly two billion years old!"

Chorrikst spoke slowly, In a throaty whisper, but her translator box was standard: voice a little flat, p.r.o.nunciation perfect. "I have circled the galaxy numberless times, and taped the tales of my travels for funds to feed my wanderl.u.s.t. Much of my life has been spent at the edge of lightspeed, under relativistic time-compression. So you see, I am not nearly so old as all that."

"The Green Marauder," 1980 .

NIGHT ON MISPEC MOOR.

One night I sat down to write a swords-and-sorcery-style horror story. This is what came out.

In predawn darkness the battle began to take shape. Helicopters circled, carrying newstapers and monitors. Below, the two armies jockeyed for position. They dared not meet before dawn. The monitors would declare a mistrial and fine both sides heavily.

In the red dawn the battle began. Scout groups probed each other's skills. The weapons were identical on both sides: heavy swords with big basket hilts. Only the men themselves differed in skill and strength.

By noon the battle had concentrated on a bare plain strewn with white boulders and a few tight circles of green Seredan vegetation. The warriors moved in little clumps. Where they met, the yellow dirt was stained red, and cameras in the helicopters caught it all for public viewing.

Days were short on Sereda. For some, today was not short enough.

As Sereda's orange dwarf sun dropped toward the horizon, the battle had become a ma.s.sacre with the Greys at the wrong end. When Tomas Vatch could no longer hold a sword, he ran. Other Greys had fled, and Amber soldiers streamed after them, yelling. Vatch ran with blood flowing down his sword arm and dripping from his fingertips. He was falling behind, and the Ambers were coming close.

He turned sharp left and kept running. The swarm moved north, toward the edge of Mispec Moor, toward civilization. Alone, he had a chance. The Ambers would not concern themselves with a single fleeing man.

But one did. One golden-skinned red-haired man shouted something, waved his sword in a circle over his head, and followed.