All the matter you're ever likely to meet will be normal matter, composed of a nucleus of protons and neutrons surrounded by electrons in quantum energy states. In the heart of any star there is a second kind of matter, for there the tremendous pressure is enough to smash the electron shells. The result is degenerate matter nuclei forced together by pressure and gravity but held apart by the mutual repulsion of the more or less continuous electron «gas» around them. The tight circumstances may create a third type of matter.

Given: a burned-out white dwarf with a mass greater than 1.44 times the mass of the sun — Chandrasekhar's Limit, named for an Indian-American astronomer of the 1900s. In such a mass the electron pressure alone would not be able to hold the electrons back from the nuclei. Electrons would be forced against protons — to make neutrons. In one blazing explosion most of the star would change from a compressed mass of degenerate matter to a closely packed lump of neutrons: neutronium, theoretically the densest matter possible in this universe. Most of the remaining normal and degenerate matter would be blown away by the liberated heat.

For two weeks the star would give off X rays as its core temperature dropped from five billion degrees Kelvin to five hundred million. After that it would be a light-emitting body perhaps ten to twelve miles across: the next best thing to invisible. It was not strange that BVS-1 was the first neutron star ever found.

Neither is it strange that the Institute of Knowledge on Jinx would have spent a good deal of time and trouble looking. Until BVS-1 was found, neutronium and neutron stars were only theories. The examination of an actual neutron star could be of tremendous importance. Neutron stars might give us the key to true gravity control.

Mass of BVS-1: 1.3 times the mass of Sol, approx.

Diameter of BVS-1 (estimated): eleven miles of neutronium, covered by half a mile of degenerate matter, covered by maybe twelve feet of ordinary matter.

Nothing else was known of the tiny hidden star until the Laskins went in to look. Now the Institute knew one thing more: the star's spin.

«A mass that large can distort space by its rotation,» said the puppeteer. «The Laskins' projected hyperbola was twisted across itself in such a way that we can deduce the star's period of rotation to be two minutes twenty-seven seconds.

The bar was somewhere in the General Products building. I don't know just where, and with the transfer booth's it doesn't matter. I kept staring at the puppeteer bartender. Naturally only a puppeteer would be served by a puppeteer bartender, since any biped life-form would resent knowing that his drink had been made with somebody's mouth. I had already decided to get dinner somewhere else.

«I see your problem,» I said. «Your sales will suffer if it gets out that something can reach through one of your hulls and smash a crew to bloody smears. But where do I come in?»

«We want to repeat the experiment of Sonya Laskin and Peter Laskin. We must find —»

«With me?»

«Yes. We must find out what it is that our hulls cannot stop. Naturally you may —»

«But I won't.»

«We are prepared to offer one million stars.»

I was tempted, but only for a moment. «Forget it.»

«Naturally you will be allowed to build your own ship, starting with a No. 2 General Products hull.»

«Thanks, but I'd like to go on living.»

«You would dislike being confined. I find that We Made It has reestablished the debtor's prison. If General Products made public your accounts —»

«Now, just a —»

«You owe money on the close order of five hundred thousand stars. We will pay your creditors before you leave. If you return —» I had to admire the creature's honesty in not saying «When.» «— we will pay you the residue. You may be asked to speak to news commentators concerning the voyage, in which case there will be more stars.»

«You say I can build my own ship?»

«Naturally. This is not a voyage of exploration. We want you to return safely.»

«It's a deal,» I said.

After all, the puppeteer had tried to blackmail me. What happened next would be its own fault.

They built my ship in two weeks flat. They started with a No. 2 General Products hull, just like the one around the Institute of Knowledge ship, and the lifesystem was practically a duplicate of the Laskins', but there the resemblance ended. There were no instruments to observe neutron stars. Instead, there was a fusion motor big enough for a Jinx warliner. In my ship, which I now called Skydiver, the drive would produce thirty gees at the safety limit. There was a laser cannon big enough to punch a hole through We Made It's moon. The puppeteer wanted me to feel safe, and now I did, for I could fight and I could run. Especially I could run.

I heard the Laskins' last broadcast through half a dozen times. Their unnamed ship had dropped out of hyperspace a million miles above BVS-1. Gravity warp would have prevented their getting closer in hyperspace. While her husband was crawling through the access tube for an instrument check, Sonya Laskin had called the Institute of Knowledge. «… We can't see it yet, not by naked eye. But we can see where it is. Every time some star or other goes behind it, there's a little ring of light. Just a minute. Peter's ready to use the telescope …»

Then the star's mass had cut the hyperspatial link. It was expected, and nobody had worried — then. Later, the same effect must have stopped them from escaping from whatever attacked them into hyperspace.

When would-be rescuers found the ship, only the radar and the cameras were still running. They didn't tell us much. There had been no camera in the cabin. But the forward camera gave us, for one instant, a speed-blurred view of the neutron star. It was a featureless disk the orange color of perfect barbecue coals, if you know someone who can afford to burn wood. This object had been a neutron star a long time.

«There'll be no need to paint the ship,» I told the president.

«You should not make such a trip with the walls transparent. You would go insane.»

«I'm no flatlander. The mind-wrenching sight of naked space fills me with mild but waning interest. I want to know nothing's sneaking up behind me.»

The day before I left, I sat alone in the General Products bar, letting the puppeteer bartender make me drinks with his mouth. He did it well. Puppeteers were scattered around the bar in twos and threes, with a couple of men for variety, but the drinking hour had not yet arrived. The place felt empty.

I was pleased with myself. My debts were all paid, not that that would matter where I was going. I would leave with not a minicredit to my name, with nothing but the ship …

All told, I was well out of a sticky situation. I hoped I'd like being a rich exile.

I jumped when the newcomer sat down across from me. He was a foreigner, a middle-aged man wearing an expensive night-black business suit and a snow-white asymmetrical beard. I let my face freeze and started to get up.

«Sit down, Mr. Shaeffer.»

«Why?»

He told me by showing me a blue disk. An Earth government ident. I looked it over to show I was alert, not because I'd know an ersatz from the real thing.

«My name is Sigmund Ausfaller,» said the government man. «I wish to say a few words concerning your assignment on behalf of General Products.»

I nodded, not saying anything.

«A record of your verbal contract was sent to us as a matter of course. I noticed some peculiar things about it. Mr. Shaeffer, will you really take such a risk for only five hundred thousand stars?»