The other, "But were they sapient? How could we ever know?"

Chirpsithra obscurities. I moved on. We were frantic for the next hour.

Then the Iraqis all rose and went out-prayer time, I guess-and suddenly most of the bar was getting up and walking, rolling, lurching, slithering through the airlock into a horizontal glare of Siberian tundra. The Low Jumbos followed the rest.

The jellyfish in his aquarium was still there. I wondered if he"d been abandoned. Five Chirpsithra who had watched their alien companions all go away now gathered around the big table with the aquarium in the center. Herman glanced my way for permission. I thumbs-upped him. He pulled up a high chair and joined them. Something hairy came out of the restroom, looked around at the empty bar, then joined Herman and the chirps and jellyfish.

Jehaneh looked tired. I told her to go sack out. Gail went too. Roger Teng-Hui was still at the bar working his Toshiba. The Terminator Beaver was deeply involved with his Macintosh.

I stopped at the Beaver"s table.

What showed of him was largely prosthetic. Under all the goo and wire and silver plating and small glowing icons the Terminator Beaver might have been a solitary Low Jumbo. He was half covered in tiny black platelets, half pink hide bared for prosthetics. Circuitry, lenses, armor covered his body. The material shone like gla.s.s and metal and jelly, but it all flexed. There was a narrow indicator strip above his small, neat carnivore"s mouth, where he could read it with goggles like two silver eggs. The widgetry had a functional beauty implying, I thought, centuries of design. It hid most of his face.

Wires ran from a neck ring into the ports of the Macintosh. The screen was dancing, flickering, and his fingers never went near it.

He"d told us his name: a near-supersonic birdsong. He had been in the Draco Tavern since the landings, eating and drinking alone. He had bought the Macintosh laptop computer in Forelgrad, the merchant town that has grown up around the s.p.a.ceport. Gail had shown him the basics during a dull evening. He"d become skilled very rapidly.

We"d speculated. The Draco Tavern"s elaborate restroom isn"t gender-specific, so we still didn"t know that. that. Was he, she, it a cyborg by choice, a medical patient, geriatric case, augmented athlete? Was he an injured Low Jumbo avoiding eyes that might find him ugly? Was he, she, it a cyborg by choice, a medical patient, geriatric case, augmented athlete? Was he an injured Low Jumbo avoiding eyes that might find him ugly?

He"d plugged his Mac into the wall, not into one of the universal sockets the Chirpsithra gave us, but into a telephone jack. I looked back toward the bar. Teng-Hui was around the other side, not visible.

The Beaver might well be the mysterious . . Did I want Teng-Hui to know that? Did I want to tell the Beaver about Teng-Hui? Did I want Teng-Hui to know that? Did I want to tell the Beaver about Teng-Hui?

I try not to get myself or the Tavern involved in these dominance games. Sometimes there"s no helping it. And sometimes I can supplement our income by learning something valuable. I once went broke building a supercomputer, but that"s also how I patented the magnetic float.

The game the Beaver was playing wasn"t an action game, so I felt free to interrupt. "Terminator Beaver," I said, and let my translator whistle his name, "how are you doing?"

Let him take it either way: progress on the game, or was he thirsty?

He whistle-sang. His translator said, "Dead. Notice joke. I begin the game dead."

"Your character can still get hurt." He was playing Grim Fandango Grim Fandango upgraded for 3-D. I watched him trying to deal with the coroner and his flower beds. "Do you enjoy hints?" upgraded for 3-D. I watched him trying to deal with the coroner and his flower beds. "Do you enjoy hints?"

"No."

"I need a hint to a puzzle. How good are you with that thing?"

"A fascinating toy."

"Have you had dealings with this ent.i.ty?" I showed him the net address: . .

He asked, "Do you have access to this ent.i.ty?" He typed it on the screen: . .

"It may be. Describe what you want of him."

"A matter of negotiations. Rick Schumann, why should I tell you more?"

" "ChinaRoger" hasn"t dealt with aliens."

"You have had much experience. I have funds if you will act as a mediator," said the Terminator Beaver.

"I"ve done that," I acknowledged. "How difficult is my task to be? Try to describe what you want of "chinaRoger." "

"I seek knowledge that would point to energy for industrial purposes."

Guessing, I asked, "Something to do with the missing ma.s.s?"

"I wondered if you merely pretended to knowledge. Would you accept one-over-twelve-cubed of net profits from this process over the next thousand years?"

I negotiated for half that, plus a modest thousand credits to be transferred at once. A bird in the hand, etc. The recording would serve as a contract if I brought these two together. I hadn"t decided on that. Either way, I expected no profit from this.

Herman was getting recharged sparkers for his table. The Wheesthroo, the hairy guy, wanted an orange sherbet shake in odd proportions. I made that and Herman took it away.

Teng had waited patiently. I asked him, "What do you want with this "Helmuthdip"?"

"I want to know what he he wants with wants with me me."

"What"s he say he wants?"

"That"s complicated."

"I"m not busy."

"I thought he was just another astrophysicist. But, look, I"m Roger Teng-Hui. Roger Teng-Hui. Any decent astrophysicist news who I am, and I"d know who he was. I don"t mind "Helmuthdip" hiding his name. But he knows of research I"ve never heard of, and there are terms he didn"t know. Any decent astrophysicist news who I am, and I"d know who he was. I don"t mind "Helmuthdip" hiding his name. But he knows of research I"ve never heard of, and there are terms he didn"t know. That That was funny. He wanted to talk about the expanding universe, but he didn"t know "Hubble constant." He knew "missing ma.s.s," but he didn"t know "Casimir effect." " was funny. He wanted to talk about the expanding universe, but he didn"t know "Hubble constant." He knew "missing ma.s.s," but he didn"t know "Casimir effect." "

"I don"t either."

"Ah. Look, this is fascinating stuff-" He caught himself. "Even now. Rick, the current most interesting question in astrophysics is, what is the nature of the expansion of the universe? Will the universe expand to infinity, or will it collapse back to a point? Most astrophysicists would like to find just enough matter to make s.p.a.ce flat.

"Understand this picture? If the universe is too ma.s.sive, it"ll expand for a while and then fall back into a reverse Big Bang. If there"s not enough ma.s.s, it"ll be expanding toward infinite volume. Right between, it expands to a finite limit. That"s flat s.p.a.ce, right between infinite expansion and an eventual collapse, and it fits a cl.u.s.ter of theories built around an inflationary universe. How fast we"re expanding is the Hubble constant."

I did in fact understand him, but he didn"t wait to find that out, he just raced on. "Now, the right amount of matter to do that depends on how fast the galaxies are going away from each other ... the Hubble constant, right? The faster they"re flying apart, the more energetic the Big Bang explosion must have been, and the more ma.s.s it will take to pull everything to a stop.

"The point is, none of the astronomers can find enough ma.s.s to do the job. Maybe we would have. Telescopes were getting better all the time, but then the Chirpsithra showed up-"

"Is this what was going on at "Helmuthdip"s" Web site?"

"Yes. I thought he was an amateur at first. Brilliant amateur. I was intrigued.

"The latest, most accurate measurement of the Hubble constant depends on Type 1A supernova explosions. Do you know how that that works?" I shook my head. "Say you"ve got a bloated gas giant star losing ma.s.s to a white dwarf companion. The hot hydrogen gas rains down through an amazing gravity field, so it"s heated to tens of millions of degrees. When it gets dense enough, you get a fusion bomb, works?" I shook my head. "Say you"ve got a bloated gas giant star losing ma.s.s to a white dwarf companion. The hot hydrogen gas rains down through an amazing gravity field, so it"s heated to tens of millions of degrees. When it gets dense enough, you get a fusion bomb, boom. boom.

"These Type 1A"s all resemble each other, and they can be recognized across huge distances. The universe is full of them. A Type 1A supernova tells you how far away it is by how bright it is, and how fast it"s moving by its red shift.

"Using those as meters to measure the universe, we get a rate of expansion that suggests around thirty percent of the ma.s.s that"s needed to close the universe, or ten percent, or seventy percent, depending on who needs a grant. "

"So you look for more ma.s.s."

"Right! We look in places obscure and weird. We postulate ma.s.s we can"t see, dark matter, in all sizes from neutrinos to intergalactic dust, to near infinities of brown dwarf stars, to hypothetical ma.s.sive particles left over from the Big Bang itself. I wasn"t a front-runner in all this, but I kept track. And I got old, and we had too many solutions and none of them made a lot of sense. Aliens came down in Siberia, hordes of them, and they know. they know. So what was the point? So what was the point?

"Then "Helmuthdip" popped up on my screen. And for a while he was making sense, and then he got into the Casimir effect."

"What brought you here?"

"And then he started insisting that I use my influence influence on the pilots of an interstellar liner! That would have brought me here anyway, but on the pilots of an interstellar liner! That would have brought me here anyway, but what what influence? If he comes from a place where astrophysicists have more power than f.u.c.king politicians, it"s for d.a.m.n sure he"s from interstellar s.p.a.ce! But I have to tell you about the Casimir effect." influence? If he comes from a place where astrophysicists have more power than f.u.c.king politicians, it"s for d.a.m.n sure he"s from interstellar s.p.a.ce! But I have to tell you about the Casimir effect."

"Do you really?"

"Actually," he said, "no. Let"s leave it that there"s energy in the vacuum. Fantastic levels. s.p.a.ce isn"t really empty, it"s a froth of virtual particles appearing and annihilating each other faster than any hypothetical instrument can detect them, and that"s where the energy is. It"s been demonstrated mathematically that if the vacuum in free s.p.a.ce was empty of energy, you"d have minus minus energy near a black hole. energy near a black hole.

"The Casimir effect is an experiment that measures measures vacuum energy. You machine two plates very flat, and you move them very close together. They pull at each other-" vacuum energy. You machine two plates very flat, and you move them very close together. They pull at each other-"

"Gravity?"

"No."

"Oh."

"It"s done with virtual particles. Virtual particles flash into existence and annihilate each other everywhere in s.p.a.ce. But you put these plates so close together that the wavelength between the two plates is too small. There"s no room for virtual particles to pop up between them. The pressure on the outsides pushes the plates together, and that"s the Casimir effect."

"Strong?"

"Tiny. "Helmuthdip" has been trying to tell me-Is that ent.i.ty waving at you? The half-mechanical, ah, person?"

The Terminator Beaver was on his feet and coming around the bar. I said, "Terminator Beaver, meet Roger Teng-Hui, also known as "chinaRoger." Teng, meet "Helmuthdip," aka Terminator Beaver. I believe you have much to discuss."

They sat at the bar with their computers in front of them, sometimes activating displays to supplement the Chirpsithra translators. They both kept slipping into jargon, then remembered that they were talking to the bartender too. Sometimes it takes a third party to get two people talking the same language.

"The Chirpsithra won"t discuss what powers their star-to-star liners," the Terminator Beaver said. "Our landers are various and we build them ourselves, but the liners have apparent infinite power and not enough fuel storage."

"Antimatter?" Teng asked.

"Antimatter they keep for att.i.tude jets, with dross from refined sewage as reaction ma.s.s. Our landers landers use antimatter. Spies have identified a system aboard use antimatter. Spies have identified a system aboard Scrilbree Zesh Scrilbree Zesh for for making making antimatter! Where do they get the energy? Many species wish to solve the puzzle. Sometimes we cooperate. We know that the liner"s ma.s.s varies during a voyage, losing and gaining again." antimatter! Where do they get the energy? Many species wish to solve the puzzle. Sometimes we cooperate. We know that the liner"s ma.s.s varies during a voyage, losing and gaining again."

"The energy of the vacuum is thinly spread," Teng said.

"By some measurements," the Beaver agreed. "Some theories render it huge. The Casimir effect may measure only the least of what is available."

I saw fit to cut in. "Near-infinite energy in the vacuum," I said, "and near-infinite energy in these huge Chirpsithra ships. That isn"t all of your argument, is it? Because they don"t have to be related."

They both tried to interrupt. The Beaver"s translator cried, "No, no, no! What of the missing ma.s.s?"

"He was doing that before," Teng said. "It"s an interesting ... notion."

"We must suppose that early Chirpsithra-" The Beaver saw us about to object. "No? Then think of engineers who find a way to attain the energy of the vacuum. When work is done, something always disappears, does it not? Not energy nor potential nor ma.s.s, unless one into the other, but something is gone."

"Entropy," Teng said. "Disorder increases. Energy becomes less available."

"Yes, but what is gone when energy is taken from the vacuum?" The Beaver"s silver goggles flickered as he studied our faces. "You cannot pull energy from the same volume over and over!" he snapped. "Vacuum must disappear!"

I said, "Okay-"

"They learn the ultimate secret, these Engineers. They may be the first of many. Their numbers and ambitions expand. Peculiar and active galaxies may show their work. There is no missing ma.s.s," the Beaver said. "The universe is expanding too fast, the Bang was too energetic, but expansion slows because s.p.a.ce is disappearing. In the limit, s.p.a.ce will be flat."

I asked, "Teng? Is this even sane?"

The man said, "Oh ... sane. Look, there"s no way you can take the same energy out of the same block of emptiness forever. Energy has to become less available. Sure Sure something has to go, and it"s probably volume. s.p.a.ce shrinks where the Engineers have pa.s.sed. Why the Chirpsithra?" something has to go, and it"s probably volume. s.p.a.ce shrinks where the Engineers have pa.s.sed. Why the Chirpsithra?"

"Look about you. They They have such a power source! How many suspects can you identify?" the Beaver demanded, rather unfairly, since the bar had been nearly emptied. have such a power source! How many suspects can you identify?" the Beaver demanded, rather unfairly, since the bar had been nearly emptied.

Teng said, "Well, that"s my point. This universe has had around ten to the tenth years to produce a species capable of using the energy of the vacuum. We expect the universe to last ... how long before interesting things stop happening? Ten to the fortieth years? Ten to the ten to the eighty? We are in the earliest moment of the universe. Most of time is in front of us. The Engineers might not even have a planet to evolve on yet! They may evolve after all the protons have disappeared."

I said to the Beaver, "You have asked the Chirpsithra, haven"t you?"

"To us the Chirpsithra said nothing. To another race they once said that the secret of their drive was to be taken as a puzzle. "Just another cursed intelligence test." "

Teng burst out, "Your d.a.m.n hypothesis isn"t even falsifiable!"

I asked, "What?"

"When you"ve got a decent theory, you try to falsify it, Rick. You don"t want someone else making you look like a fool, so you try to disprove it yourself first. If a statement can"t can"t be disproved, falsified be disproved, falsified if if it"s false, it"s useless. Beaver, if the Engineers won"t start chewing up galaxies for a trillion trillion years, what evidence would you expect to find it"s false, it"s useless. Beaver, if the Engineers won"t start chewing up galaxies for a trillion trillion years, what evidence would you expect to find now?" now?"

"Any species may ask."

"Not us," Teng said, suddenly bitter. "There weren"t even human footprints on Mars when the Chirpsithra came. If ever there are, they"ll be around a Chirpsithra landing site. Pa.s.sengers. Why would they give us us an interstellar drive? We can"t even build landers, and they use antimatter just for reaction jets!" an interstellar drive? We can"t even build landers, and they use antimatter just for reaction jets!"

I made two cappuccinos while I thought. All talk stopped in the scream of steam.

It seems I"m doomed to spend my life with ent.i.ties brighter and more knowledgeable than myself. They gather to talk, all these different shapes and minds, and I am privileged to listen. I love it. But sometimes they talk and talk, and never act.

A mathematician once told me that all of math is a mind game. The strangest thing is that any of mathematics can be fitted into the way any part of the universe behaves. The huge vacuum energies that fall out of mathematical formulations needn"t be taken seriously. I knew that without ever seeing the equations, let alone being able to read them.

Then again ... "Come with me," I said. "Let me do the talking. Teng, you may not know it, but any ongoing conversation should not be interrupted. It"s a custom."

"Right. What have you got in mind?" But I was in motion, and what I had in mind was very little.

The big table was down to Herman, three Chirpsithras, the silent Wheesthroo, and the big jellyfish in his aquarium jar. I placed the cappuccinos and pulled up high chairs for the rest of us. One of the Chirps was chittering. My translator said, "Not all of the life-forms known to us enter the Draco Tavern. Poseidon ma.s.ses as much as Scrilbree Zesh Scrilbree Zesh itself." itself." Scrilbree Zesh Scrilbree Zesh was the big ship still orbiting the Moon. was the big ship still orbiting the Moon.