We were having little luck with chemical analysis 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 damn 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 mass 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 hell 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 geophysicaclass="underline" 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 mass, if there was a mass, was at rest in there. It was strange to see the Forward Mass 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 nobody 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 buttons on what might have been an alien typewriter keyboard.
Childrey looked startled. He slapped at his right thigh and brought the hand away bloody. 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 button. It must have switched off the fields that held the mass in place. It just dropped. Captain Childrey was underneath."
And it had gone straight through him, eating the mass of him as it went.
"No, not quite," said Lear. "I'd guessed it massed 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 passed 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 mass from the way it behaved?
Lear spread his hands. "Gentlemen, we're dealing with more variables than just mass. Field strength, for instance. I might have guessed its mass 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 bypassed 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."
"Hell, 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 mass of the entire setup with the Forward Mass Sensor. Now the black hole isn't in there any more. I can get the mass of the black hole by taking the mass of the communicator alone."
"And I can cut the machine open, see what's inside. How they controlled it. Damn 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 mass. 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...