I discovered the field for myself as a teenager (as did almost everyone else I knew — in school we were tormented with Wordsworth and Bunyan, while Clarke and Heinlein had to be private after-school pleasures). Knowing at the time a negligible amount of real science, I swallowed whole and then regurgitated to my friends everything presented as science in the SF magazines. That quickly built me a reputation as a person stuffed with facts and theories — many of them wrong and some of them decidedly weird. The writers didn’t bother to distinguish the scientific theories that they borrowed, from the often peculiarly unscientific theories that they made up for the story. Neither did I.
I knew all about the canals on Mars, the dust pools on the Moon, and the swamps on Venus, about the Dean drive and dianetics and the Hieronymus machine. I believed that men and pigs were more closely related than men and monkeys; that atoms were miniature solar systems; that you could shoot men to the moon with a cannon (a belief that didn’t survive my first course in dynamics); that the pineal gland was certainly a rudimentary third eye and probably the seat of parapsychological powers; that Rhine’s experiments at Duke University had made telepathy an unquestioned part of modern science; that with a little ingenuity and a few electronic bits and pieces you could build in your backyard a spacecraft to take you to the moon; and that, no matter what alien races might have developed on other worlds and be scattered around the Galaxy, humans would prove to be the smartest, most resourceful, and most wonderful species to be found anywhere.
That last point may even be true. As Pogo remarked long ago, true or false, either way it’s a mighty sobering thought.
What I needed was a crib sheet. We had them in school for the works of Shakespeare. They were amazingly authoritative, little summaries that outlined the plot, told us just who did what and why, and even informed us exactly what was in Shakespeare’s head when he was writing the play. If they didn’t say what he had for lunch that day, it was only because that subject never appeared on examination papers. Today’s CliffsNotes are less authoritative, but only I suspect because the changing climate of political correctness encourages commentators to be as bland as possible.
I didn’t know it at the time, but the crib sheets were what I was missing in science fiction. Given the equivalent type of information about SF, I would not have assured my friends (as I did) that the brains of industrial robots made use of positrons, that the work of Dirac and Blackett would lead us to a faster-than-light drive, or that the notebooks of Leonardo da Vinci gave all the details needed to construct a moon rocket.
As Mark Twain remarked, it’s not what we don’t know that causes the trouble, it’s the things we know that ain’t so. (This is an example of the problem. I was sure this was said by Mark Twain, but when I looked it up I found it was a Josh Billings line. Since then I have seen it as attributed to Artemus Ward.) What follows, then, is my crib sheet for this book. This Appendix sorts out the real science, based on and consistent with today’s theories (but probably not tomorrow’s), from the “science” that I made up for these stories. I have tried to provide a clear dividing line, at the threshold where fact stops and fiction takes over. But even the invented material is designed to be consistent with and derived from what is known today. It does not contradict current theories, although you will not find papers about it in the Physical Review or the Astrophysical Journal.
The reader may ask, which issues of these publications? That’s a very fair question. After all, these stories were written over a twenty-year period. In that time, science has advanced, and it’s natural to ask how much of what I wrote still has scientific acceptance.
I reread each story with that in mind, and so far as I know everything still fits with current knowledge. A few things have even gained in plausibility. For example, when I wrote “Rogueworld” we had no direct evidence of any extra-solar planets. Now reports come in every month or two of another world around some other star, based not on direct observation of the planet but on small observed perturbations in the apparent position of the star itself. The idea of vacuum energy extraction, first introduced to science fiction in “All the Colors of the Vacuum,” has proceeded from wild science fiction idea to funded research. Black holes, which at the time I wrote “Killing Vector” were purely theoretical entities, form a standard part of modern cosmology. A big black hole, about 2.5 million times the mass of the Sun, is believed to lie at the center of our own galaxy. Radiating black holes, which in 1977 were another way-out idea, are now firmly accepted. The Oort cloud, described in “The Manna Hunt,” is a standard part of today’s physical model of the extended Solar System.
So has there been nothing new in science in the past twenty years? Not at all. Molecular biology has changed so fast and so much since the 1970s that the field seen from that earlier point of view is almost unrecognizable, and the biggest changes still lie in the future. Computers have become smaller, more powerful, and ubiquitous, beyond what anyone predicted twenty years ago. We also stand today on the verge of quantum computation, which takes advantage of the fact that at the quantum level a system can exist in several states simultaneously. The long-term potential of that development is staggering.
Finally, in the very week that I write this, a report has appeared of the first successful experiment in “quantum teleportation.” Via a process known as “entanglement,” which couples the quantum state of two widely separated systems, a Caltech team “teleported” a pattern of information from one location to another, independent of the speed of light. If there isn’t a new hard SF story in that report, I don’t know where you’ll find one.
Kernels, black holes, and singularities.
Kernels feature most prominently in the first chronicle, but they are assumed and used in all the others, too. A kernel is actually a Ker-N-le, which is shorthand for Kerr-Newman black hole.
To explain Kerr-Newman black holes, it is best to follow McAndrew’s technique, and go back a long way in time. We begin in 1915. In that year, Albert Einstein published the field equations of general relativity in their present form. He had been trying different possible formulations since about 1908, but he was not satisfied with any of them before the 1915 set. His final statement consisted of ten coupled, nonlinear, partial differential equations, relating the curvature of space-time to the presence of matter.
The equations are very elegant and can be written down in tensor form as a single short line of algebra. But written out in full they are horrendously long and complex — so much so that Einstein himself did not expect to see any exact solutions, and thus perhaps didn’t look very hard. When Karl Schwarzschild, just the next year, produced an exact solution to the “one-body problem” (he found the gravitational field produced by an isolated mass particle), Einstein was reportedly quite surprised.
This “Schwarzschild solution” was for many years considered mathematically interesting, but of no real physical importance. People were much more interested in looking at approximate solutions of Einstein’s field equations that could provide possible tests of the theory. Everyone wanted to compare Einstein’s ideas on gravity with those introduced two hundred and fifty years earlier by Isaac Newton, to see where there might be detectible differences. The “strong field” case covered by the Schwarzschild solution seemed less relevant to the real world.
For the next twenty years, little was discovered to lead us toward kernels. Soon after Schwarzschild published his solution, Reissner and Nordstrom solved the general relativity equations for a spherical mass particle that also carried an electric charge. This included the Schwarzschild solution as a special case, but it was considered to have no physical significance and it too remained a mathematical curiosity.