«Of course you'd never detect anything that small,» said Carlos. He seemed almost cheerful. I wondered why … and then I knew. He'd been right about the way the ships were disappearing. It must compensate him for being tied to a pillar.
«But,» said Forward, «black holes of all sizes could have formed in that explosion, and should have. In more than seven hundred years of searching no quantum black hole has ever been found. Most cosmologists have given up on them, and on the big bang, too.»
Carlos said, «Of course there was the Tunguska meteorite. It could have been a black hole of, oh, asteroidal mass —»
«— and roughly molecular size. But the tide would have pulled down trees as it went past —»
«— and the black hole would have gone right through the Earth and headed back into space a few tons heavier. Eight hundred years ago there was actually a search for the exit point. With that they could have charted a course —»
«Exactly. But I had to give up that approach,» said Forward. «I was using a new method when the Institute, ah, severed our relationship.»
They must both be mad, I thought. Carlos was tied to a pillar and Forward was about to kill him, yet they were both behaving like members of a very exclusive club … to which I did not belong.
Carlos was interested. «How'd you work it?»
«You know that it is possible for an asteroid to capture a quantum black hole? In its interior? For instance, at a mass of ten to the twelfth kilograms — a billion metric tons,» he added for my benefit, «a black hole would be only one point five times ten to the minus fifth angstroms across. Smaller than an atom. In a slow pass through an asteroid it might absorb a few billions of atoms, enough to slow it into an orbit. Thereafter it might orbit within the asteroid for eons, absorbing very little mass on each pass.»
«So?»
«If I chance on an asteroid more massive than it ought to be, and if I contrive to move it, and some of the mass stays behind …»
«You'd have to search a lot of asteroids. Why do it out here? Why not the asteroid belt? Oh, of course. You can use hyperdrive out here.»
«Exactly. We could search a score of masses in a day, using very little fuel.»
«Hey. If it was big enough to eat a spacecraft, why didn't it eat the asteroid you found it in?»
«It wasn't that big,» said Forward. «The black hole I found was exactly as I have described it. I enlarged it. I towed it home and ran it into my neutronium sphere. Then it was large enough to absorb an asteroid. Now it is quite a massive object. Ten to the twentieth power kilograms, the mass of one of the larger asteroids, and a radius of just under ten to the minus fifth centimeters.»
There was satisfaction in Forward's voice. In Carlos's there was suddenly nothing but contempt. «You accomplished all that, and then you used it to rob ships and bury the evidence. Is that what's going to happen to us? Down the rabbit hole?»
«To another universe, perhaps. Where does a black hole lead?»
I wondered about that myself.
Angel had taken Forward's place at the control console. He had fastened the seat belt, something I had not seen Forward do, and was dividing his attention between the instruments and the conversation.
«I'm still wondering how you move it,» said Carlos. Then, «Uh! The tugs!»
Forward stared, then guffawed. «You didn't guess that? But of course the black hole can hold a charge. I played the exhaust from an old ion drive reaction motor into it for nearly a month. Now it holds an enormous charge. The tugs can pull it well enough. I wish I had more of them. Soon I will.»
«Just a minute,» I said. I'd grasped one crucial fact as it had gone past my head. «The tugs aren't armed? All they do is pull the black hole?»
«That's right.» Forward looked at me curiously.
«And the black hole is invisible.»
«Yes. We tug it into the path of a spacecraft. If the craft comes near enough, it will precipitate into normal space. We guide the black hole through its drive to cripple it, board and rob it at our leisure. Then a slower pass with the quantum black hole, and the ship simply disappears.»
«Just one last question,» said Carlos. «Why?»
I had a better question.
Just what was Ausfaller going to do when three familiar spacecraft came near? They carried no armaments at all. Their only weapon was invisible.
And it would eat a General Products hull without noticing.
Would Ausfaller fire on unarmed ships?
We'd know too soon. Up there, near the edge of the dome, I had spotted three tiny lights in a tight cluster.
Angel had seen it, too. He activated the phone. Phantom heads appeared, one, two, three.
I turned back to Forward and was startled at the brooding hate in his expression.
«Fortune's child,» he said to Carlos. «Natural aristocrat. Certified superman. Why would you ever consider stealing anything? Women beg you to give them children, in person if possible, by mail if not! Earth's resources exist to keep you healthy, not that you need them!»
«This may startle you,» said Carlos, «but there are people who see you as a superman.»
«We bred for strength, we Jinxians. At what cost to other factors? Our lives are short, even with the aid of boosterspice. Longer if we live outside Jinx's gravity. But the people of other worlds think we're funny. The women … never mind.» He brooded, then said it anyway. «A woman of Earth once told me she would rather go to bed with a tunneling machine. She didn't trust my strength. What woman would?»
The three bright dots had nearly reached the center of the dome. I saw nothing between them. I hadn't expected to. Angel was still talking to the pilots.
Up from the edge of the dome came something I didn't want anyone to notice. I said, «Is that your excuse for mass murder, Forward? Lack of women?»
«I need give you no excuses at all, Shaeffer. My world will thank me for what I've done. Earth has swallowed the lion's share of the interstellar trade for too long.»
«They'll thank you, huh? You're going to tell them?»
«Julian!» That was Angel calling. He'd seen it … no, he hadn't. One of the tug captains had.
Forward left us abruptly. He consulted with Angel in low tones, then turned back. «Carlos! Did you leave your ship on automatic? Or is there someone else aboard?»
«I'm not required to say,» said Carlos.
«I could — no. In a minute it will not matter.»
Angel said, «Julian, look what he's doing.»
«Yes. Very clever. Only a human pilot would think of that.»
Ausfaller had maneuvered the Hobo Kelly between us and the tugs. If the tugs fired a conventional weapon, they'd blast the dome and kill us all.
The tugs came on.
«He still does not know what he is fighting,» Forward said with some satisfaction.
True, and it would cost him. Three unarmed tugs were coming down Ausfaller's throat, carrying a weapon so slow that the tugs could throw it at him, let it absorb Hobo Kelly, and pick it up again long before it was a danger to us.
From my viewpoint Hobo Kelly was a bright point with three dimmer, more distant points around it. Forward and Angel were getting a better view through the phone. And they weren't watching us at all.
I began trying to kick off my shoes. They were soft ship slippers, ankle-high, and they resisted.
I kicked the left foot fire just as one of the tugs flared with ruby light.
«He did it!» Carlos didn't know whether to be jubilant or horrified. «He fired on unarmed ships!»
Forward gestured peremptorily. Angel slid out of his seat. Forward slid in and fastened the thick seat belt. Neither had spoken a word.
A second ship burned fiercely red, then expanded in a pink cloud.
The third ship was fleeing.
Forward worked the controls. «I have it in the mass indicator,» he rasped. «We have but one chance.»