"What are you talking about?"
Joe said, "Granted I'm a computertechnologist and not a virologist-but it's my understanding that viruses on Earth, or `downstairs' as you would say, consist of a nucleic acid molecule coated in a protein shell.
"When a virus invades a cell, it manages to dissolve a hole in the cell wall or membrane by the use of some appropriate enzyme and the nucleic acid slips inside, leaving the protein coat outside. Inside the cell it finds the material to make a new protein coat for itself. In fact, it manages to form replicas of itself and produces a new protein coat for each replica. Once it has stripped the cell of all it has, the cell dissolves and in place of the one invading virus there are several hundred daughter-viruses. Sound familiar?"
"Yes. Very familiar. It's what's happening here. But where did it come from, Joe?"
"Not from Earth, obviously, or any Earth settlement. From somewhere else, I suppose. They drift through space till they find something appropriate in which they can multiply. They look for sizable objects ready-made of metal. I don't imagine they can smelt ores."
"But large metal objects with pure silicon components and a few other succulent matters like that are the products of intelligent life only," I said.
"Right," said Joe, "which means we have the best evidence yet that intelligent life is common in the universe, since objects like the one we're on must be quite common or it couldn't support these viruses. And it means that intelligent life is old, too, perhaps ten billion years old-long enough for a kind of metal evolution, forming a metal/silicon/oil life as we have formed a nucleic/protein/water life. Time to evolve a parasite on space-age artifacts."
I said, "You make it sound that every time some intelligent life-form develops a space-culture, it is subjected before long to parasitic infestation."
"Right. And it must be controlled. Fortunately, these things are easy to kill, especially now when they're forming. Later on, when ready to burrow out of Computer-Two, I suppose they will grow, thicken their shells, stabilize their interior and prepare, as the equivalent of spores, to drift a million years before they find another home. They might not be so easy to kill then."
"How are you going to kill them?"
"I already have. I just touched that first one when it instinctively sought out metal to begin manufacturing a new shell after I had broken open the first one-and that touch finished it. I didn't touch the second, but I kicked the wall near it and the sound vibration in the metal shook its interior apart into metal dust. So they can't get us-or any more of the computer-if we just shake them apart, now!"
He didn't have to explain further-or as much. He put on his gauntlets slowly, and banged at the wall with one. It pushed him away and he kicked at the wall where he next approached it.
"You do the same," he shouted.
I tried to, and for a while we both kept at it. You don't know how hard it is to hit a wall at zero-gravity; at least on purpose; and do it hard enough to make it clang. We missed as often as not or just struck a glancing blow that sent us whirling but made virtually no sound. We were panting with effort and aggravation in no time.
But we had acclimated ourselves. We kept it up and eventually gathered up more of the viruses. There was nothing inside but dust in every case. They were clearly adapted to empty, automated space objects which, like modern computers, were vibration-free. That's what made it possible, I suppose, to build up the exceedingly rickety-complex metallic structures that possessed sufficient instability to produce the properties of simple life.
I said, "Do you think we got them all?"
"How can I say? If there's one left, it will cannibalize the others for metal supplies and start all over. Let's bang around some more."
We did until we were sufficiently worn out not to care whether one was still left alive.
"Of course," I said, panting, "the Planetary Association for the Advancement of Science isn't going to be pleased with our killing them all."
Joe's suggestion as to what the P.A.A.A. could do with itself was forceful, but impractical. He said, "Look, our mission is to save Computer-Two, a few thousand lives and, as it turned out, our own lives, too. Now they can decide whether to renovate this computer or rebuild it from scratch. It's their baby.
"The P.A.A.S. can get what they can out of these dead objects and that should be something. If they want live ones, I suspect they'll find them floating about in these regions."
I said, "All right. My suggestion is we tell Computer Central we're going to jerry-rig this Computer and get it doing some work anyway, and we'll stay till a relief is up for main repairs or whatever in order to prevent any reinfestation. Meanwhile, they'd better get to each of the other Computers and set up a system that can set it to vibrating strongly as soon as the internal atmosphere shows a pressure drop." "Simple enough," said Joe, sardonically. "It's lucky we found them when we did."
"Wait a while," said Joe, and the look in his eye was one of deep trouble. We didn't find them. They found us. If metal-life has developed, do you suppose it's likely that this is the only form it takes?
"What if such life-forms communicate somehow and, across the vastness of space, others are now converging on us for the picking. Other species, too; all of them after the lush new fodder of an as-yet untouched space culture. Other species! Some that are sturdy enough to withstand vibration. Some that are large enough to be more versatile in their reactions to danger. Some that are equipped to invade our settlements in orbit. Some, for the sake of Univac, that may be able to invade the Earth for the metals of its cities.
"What I'm going to report, what I must report, is that we've been found!"