A Step Farther Out

by Jerry Pournelle

  The general reaction was simple. Davis's theoretical papers are interesting, but not terribly valuable. They assert that there's something wrong with physics. Okay, and maybe there is; but contemporary physical theory has a lot of scalps hanging from its belt. Maybe it needs changing, but not without some convincing evidence; and mathematical theories are not evidence.

  That's what I've found very hard to get across to people. In order for a "Dean Drive" or the gizmos postulated by "Davis mechanics" to work we really do have to throw out a very great deal of very fundamental physical theory. You cannot simply "convert rotary acceleration into linear thrust" and remain consistent with what we think we know. Spacedrives are just impossible given current theory. If you want to move a ship in inertial space, you have got to throw reaction mass out the back end, and that's all there is to it.

  Now, sure, theory can be wrong. Einstein did his thing, and Newtonian physics has never been the same. We've yet to come to the end of the changes wrought by quantum mechanics. Moreover, what with 100 and more elementary particles kicking around, many believe that physics is due for a restructuring along the order of the changes rung in by Einstein.

  But note: Einstein didn't generate his theory out of pure math. Far from it. His contributions came in explanation of observed phenomena that simply couldn't be explained by Newtonian concepts. The change in the perihelion of Mercury; the photo-electric effect; the Michaelson-Morely experiment; all these said, loudly, that there was something wrong with physics and it was time to get up a new theory.

  Davis, on the other hand, played about with math and came up with "predictions" absolutely impossible within present physical theory. Is there any wonder that no one takes them seriously? Now a working "Dean Machine" would change all that. If you can actually build a gizmo that produces thrust without throwing mass overboard-even a tiny thrust—then there's nothing for it: physics is in trouble, and new theory must be found. Without such evidence, though, there's simply no reason to revise physics theory. After all, the "orthodox" stuff works quite well. It fits the observed universe.

  Now: there remains Harry Stine's memory, after all these years, of that machine pushing against his hand. One result of our conference was a consensus that if the Dean Machine did not work, it at least did not employ any of the common means of producing spurious results. It didn't have feet that periodically touched the floor, and such like. That doesn't mean it worked the way Dean said; it just means we don't know how the result was obtained.

  Then too, when Harry Stine was working for William Davis, Stine built a couple of gadgets (see Harry's Analog article for details) that gave results you certainly wouldn't have predicted in advance. They may be explainable in "normal" theory, but they are a bit queer, and they do fit Dr. Davis's theories.

  The upshot of our meeting was this: the theoretical stuff can wait. What's important is that Harry Stine, as one of the few men now alive who actually saw the Dean Machine and also worked with experimental gadgetry to test Davis mechanics, get his experimental results into proper form and publish them. That's what's important. Evidence. As Bob Forward observed, once the plans are published, one of these days a research physicist will build the apparatus: and if several different labs get the results Harry did, and have no conventional explanation for them, then it will be time to trot out the theories. "One good experimental result is worth a thousand theories," Forward said; and he's right.

  Back in the old days a number of us built Dean Machines from the patent specifications. We had technicians and they had to be paid between jobs; might as well use them to test new ideas. None of the gizmos worked. I now know of four that were built. Harry Stine can explain that: Dean, being, uh, highly suspicious, didn't describe his actual gadget in the patent. Of course that's stupid, because a patent protects only what's disclosed, but it's very much in keeping with what's known about Dean's personality.

  Harry says the actual Dean Machine was the gol darndest collection of springs and slipclutches and mechanical linkages he's ever seen in his life. He also says it pushed hard against his hand, and he'll never forget that. Harry thinks Dean had something. The question is, can it be reproduced? Did it "work" as Dean thought, or did it merely act strangely? There are ways to test that, unambiguously. Until that's done, though, theory is not relevant.

  * * *

  So it's that simple. It isn't that the "establishment" won't listen, as so many would-be theorists insist; it's that the newcomers insist that physicists only listen. They have nothing to show.

  Now I get all kinds of blueprints and plans and equations from my readers. Those who send them assume, I hope rightfully, that (1) I know something of what science and technology is all about, and (2) I try to keep an open mind. I'm willing to listen.

  But please, all of you who have new ideas, keep in mind what I said earlier. If you have plans for a perpetual motion machine and you really believe it will work—why build it! Don't send out plans only and then complain that "nobody listens." Of course nobody listens; it takes a lot of effort to spot the flaw in a very complex device (one I was sent ran to fifteen pages of drawings) but the chances are good that the flaw is there. I don't care how good a theory you have to prove that you can get energy out of your swimming pool; but I care a lot if you have built the device and it works.

  Experimental results. Build the device. Make it work And then if nobody listens, something can be done. Certainly "orthodox" physics doesn't know everything. I've said myself that I believe (emotional bias only; I have no evidence) that we'll someday build faster than light ships, and yes, I suspect there might even be "spacedrives."

  But we won't find them from blueprints. It takes evidence. Once you've got that, you'll find plenty of people to listen.

  "In the Beginning . . ."

  First, let me establish something. When I go to Cal Tech I do not expect an experience out of H. P. Lovecraft. Horror may be interesting at the proper time and place, but it's not very pleasant as a total surprise.

  It started peacefully enough. Dr. Robert Forward, the Hughes Research gravity expert you've heard of here and other places, called to ask if I would be interested in meeting Stephen Hawking. Since Hawking is thought by important physicists possibly to rank alongside Newton and Einstein, it took perhaps five milliseconds to think over the proposition. I didn't even need to look at my calendar; nothing I had planned could be that important.

  A week later Larry Niven and I drove over to the California Institute of Technology. It was a bright spring afternoon. . .

  In order properly to tell this story I must now give some personal details about Professor Hawking. I've consulted his friends, who assure me that he doesn't mind.

  Stephen Hawking is quite young, early thirties at the oldest. He is a resident theoretician at Cambridge University, and he yearly produces marvels in astronomical theory, particularly in the field of black hole dynamics.

  In "Fuzzy Black Holes Have No Hair" I described Hawking's marriage of quantum mechanics to Einstein's classical relativity theories to produce the startling prediction that black holes are unstable. He is also responsible in large part for the so-called laws of black hole dynamics. An important man indeed.

  Alas, Professor Hawking suffers from a nervous-system disorder which severely impairs his speech and confines him to a wheel chair. Those who attend his lectures are warned that they must listen closely; he can be understood, but only with difficulty and concentration. Of course this would be true if he spoke with the oratorical clarity of William Jennings Bryan to such bards of the sciences as Larry Niven and me, so we were prepared to be doubly confused.

  Cal Tech's architecture is a neat blend of Old California and modern LA; arched thick-walled Monterey-style buildings with large shaded porches alternate with steel-and-glass towers and clean-lined functionalism. It sounds horrible, but the effect is actually quite pleasing. It's a nice place to be, especially if you're looking forward to hearing one of the truly great men of our time
.

  The lecture was in a small modern slant-floored room of the type sometimes called lecture theaters; the sort of classroom lecturers like. The tiered seats let everyone have a good view of the speaker and his demonstration materials, and give the speaker a good view of the audience.

  It was only partly filled: graduate students, several undergraduates, a sprinkling of faculty, one or two of the top names in theoretical physics. It was a room of serious women and men, mostly younger than I, all expectantly quiet. At the bottom of the well, the focus of attention on the stage, was an incredibly thin, very young-appearing man seated in a high-backed motorized chair of Victorian design; the chair had no flavor of the hospital about it. He wore a light suit, dark shirt, and flowered tie, and he kept his hands folded carefully in his lap as he was introduced.

  The chairman gave his credits and spoke wonderingly of how privileged we were to hear a man of this stature. No one disagreed. Not, of course, that anyone would have said anything no matter what he thought, but the total silence in the room was an obvious sign of unanimous assent.

  Hawking began to speak Everyone leaned slightly forward, straining to hear. Except for the heavily slurred voice there was absolutely no sound; you could quite literally hear a pen drop, for I dropped mine and it clattered loudly on the cement floor.

  This is the scene, then: a lecture room partly filled with very bright people, a few extremely well known in theoretical physics, others students at one of the world's most prestigious institutions. They all strain to hear a wizened young man who makes awkward gestures and speaks with a thick slur that keeps his words just at the edge of intelligibility.

  He grins like a thief. He's obviously not in pain, and he doesn't feel sorry for himself. And he tells that room of bright people that everything they thought they knew is nonsense. And he chuckles.

  He tells us that the pudding that ate Chicago may someday exist; that duplicates of each one of us may one day wander the universe; that anything can, and probably will, happen. He tells us that the universe isn't lawful, never will be lawful, never can be lawful; that we cannot ever know enough to predict the totality of events in this universe; that at best we study local phenomena that may be predictable for an unspecifiable time.

  And he laughs.

  He tells us that Cthulthu may exist after all.

  As I said, it was an afternoon of Lovecraftian horror.

  Larry and I escaped with our sanity, after first, in the question period, making certain that Hawking really did say what we thought he'd said.

  He had.

  * * *

  Stephen Hawking's lecture had originally been entitled "The Breakdown of Physics in the Region of Space-Time Singularities." The title was flashed on the screen; then another slide took its place, and Hawking chuckled. The new slide said:

  THE BREAKDOWN OF PHYSICS PHYSICISTS

  IN THE REGION OF SPACE-TIME SINGULARITIES

  He began simply enough. The principle of equivalence, he said, is well established. This is the principle that states that inertial mass, that is, the resistance of objects to being moved by an outside force, is exactly equivalent to gravitational mass, that is, the gravitational force a given mass will exert. There are not two kinds of mass.

  This was Galileo's principle, and there's the famous apocryphal story of his dropping a cannon-ball and a musket-ball from the Leaning Tower of Pisa and observing their striking the ground at the same time. Obviously if gravitational and inertial mass were different, heavy objects would not fall at the same speed as light ones.

  So far so good. Next, gravity affects light. It can bend light rays, as predicted by Einstein and observed several times in solar eclipses.

  Now in short order: the energy-momentum tensor of gravity is positive; gravity is universally attractive, not repellent. Therefore, enough mass will create a field from which no light can escape.

  The Special Theory of Relativity says that nothing can travel faster than light.

  And therefore sufficient mass must create a space-time singularity, a place which cannot be observed.

  A singularity is therefore inevitable; that is, at least one singularity must exist, provided only. (1) that Einstein's general relativity is correct; (2) gravity is truly attractive and never repellent; and (3) enough mass has ever been collected together.

  And therefore at least one singularity exists in our universe, since at the time of the Big Bang all the conditions certainly prevailed; and also, it's very likely that other singularities have been created by collapse of stars, since many stars have more than enough matter and don't have enough energy to throw that matter away as they die.

  * * *

  OKAY so far? Nothing startling here. Bit dry, but all we've shown is that singularities must exist, and nearly everyone accepts the idea now. They're hidden away inside black holes, of course, and observers are now very nearly certain that we can observe a black hole.

  Well, not observe the hole itself; but Cygnus X-l, an x-ray emitting star in the constellation Cygnus, has an invisible companion and the pair of stars, the one we can see and the one we can't, together act very like what Gal Tech's Kip Thorne predicted such a pair would act like if one were a black hole.

  So what else is new? We've proved black holes can exist, and lo, the observers think they've found one. What's scary about that?

  Nothing, so far. Holes aren't scary unless you're about to fall into one. We even understand them. We know they "have no hair," that is, that they can be completely described given their mass, M; angular momentum, J; and electric charge, Q, Given these data we can describe their shape, and predict what effect they'll have on nearby objects, and play all kinds of fascinating scientific-theory games.

  We can talk about black hole bombs, and toy with ideas on how to extract energy from them: take one rotating black hole, throw garbage into it, and you not only get rid of the garbage, but can get useful energy back out. There are speculations (not SF; just plain science) about extremely advanced civilizations using black holes for precisely that purpose.

  There's just no end to the nice things you could do with black holes, and although not many years ago they were no more than toys for theoreticians to play mental games with, black holes have become household-word objects now.

  Black holes don't make us nervous.

  Ah, but inside each black hole there lurks a singularity. This is the little beastie that breaks down physics in the nearby regions. By definition they do things we can't predict. They behave in strange ways. Up close to them time reversals can happen. How, then, can we avoid this breakdown of our nice predictable universe?

  Hawking discussed several theoretical alternatives, and dismissed each. A couple of the cases seemed to startle one of the big-name theoreticians listening to the lecture. When Hawking was finished, though, the singularities were back and inevitable. I won't pretend to have understood all of this part of the lecture; and I wouldn't bore my readers with it if I had. If you appreciate that sort of thing you'll read Hawking's paper when it comes out.

  For the rest of us I sum up by saying that he found no good alternatives; eliminating General Relativity doesn't eliminate the singularities, or else lands you in an even worse theoretical soup.

  Therefore, let us look at General Relativity; but let us add quantum theory to it. Hawking recently published that work, and I described it here.

  The important fact is that the quantum effects violate cosmic censorship. The Law of Cosmic Censorship, you may recall, states that there shall be no naked singularities; every singularity shall be decently clothed with an event horizon that prevents us from ever being able to observe it directly, and thus prevents us from observing the region in which physics breaks down.

  Thus we needn't fear the singularity. It can't affect our lives, because nothing it does can get out of that black hole "around" it.

  But adding quantum effects to General Relativity repeals cosmic censorship. Black holes evaporate. Big ones slowly, sm
all ones rapidly, all inevitably. And what of the singularity that MUST have been created by the Big Bang of creation?

  Evaporation of black holes produces naked singularities. We may play about with the concept of quantizing relativity, and Hawking did; but the conclusion was inescapable. Again I don't pretend to have followed every step, nor did most of the rest of us in that room; but several did, and they weren't pleased.

  Because now comes the punchline. The singularities emit matter and energy. And "they emit all possible configurations with equal probability. Thus, perhaps, this is why the early universe from the Big Bang singularity was in thermal equilibrium and was very nearly homogeneous and isotropic. Thermal equilibrium would represent the largest number of configurations."

  But since that time the universe has changed, and we have stars and planets and nematodes and comets and people; but the singularity must still be around. It emits. And what comes out is completely random, absolutely un-correlated. This fundamental breakdown in prediction—Hawking is saying not only that we can't predict now, but that in principle we can never predict, no matter how much we know or how smart we get or how large a computer we build—is a "consequence of the fact that General Relativity allows fundamental changes in the topology of space-time; that is, allows holes.