APPENDIX: Science Science Fiction

Writers, readers and critics of science fiction often seem unable to produce a workable definition of the field, but one of the things they usually agree on is the existence of a particular branch that is usually termed “hard” science fiction. People who like this branch will tell you it is the only subdivision that justifies the word science, and that everything else is simple fantasy; and they will use words like “authentic,” “scientifically accurate,” “extrapolative,” and “inventive” to describe it. People who don’t like it say it is dull and bland, and use words like “characterless,” “mechanical,” “gadgetry,” or “rockets and rayguns” to describe it. Some people can’t stand hard SF, others will read nothing else.

Hard science fiction can be defined in several different ways. My favorite definition is an operational one: if you can take the science and scientific speculation away from a story, and not do it serious injury, then it was not hard SF to begin with. Here is another definition that I like rather less well: in a hard SF story, the scientific techniques of observation, analysis, logical theory, and experimental test must be applied, no matter where or when the story takes place. My problem with this definition is that it would classify many mystery and fantasy stories as hard science fiction.

Whatever the exact definition, there is usually little difficulty deciding whether a particular story is “hard” or “soft” science fiction. And although a writer never knows quite what he or she has written, and readers often pull things out of a story that were never consciously put in, I certainly think of the book you are holding as probably the hardest SF that I write. Each story revolves around some element of science, and without that element the story would collapse. If the stories reflect any common theme, it is my own interest in science, particularly astronomy and physics. Because of this, and because the science is what I have elsewhere termed “borderland science” (Borderlands of Science: How to Think Like A Scientist and Write Science Fiction; Baen Books, 1999), I feel a responsibility to the reader. It is one that derives from my own early experiences with science fiction.

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.