The most important technological features of the Empire were previously published in other stories: the Alderson Drive and Langston Field.
Both were invented to Jerry Pournelle's specifications by Dan Alderson, a resident genius at Cal Tech's Jet Propulsion Laboratories. It had always been obvious that the Drive and Field would affect the cultures that used them, but until we got to work on MOTE it wasn't obvious just how profound the effects would be.
The Alderson Drive
Every SF writer eventually must face the problem of interstellar transportation. There are a number of approaches. One is to deny faster-than-light travel. This in practice forbids organized interstellar civilizations.
A second approach is to ignore General and Special Relativity. Readers usually won't accept this. It's a cop-out, and except in the kind of story that's more allegory than science fiction, it's not appropriate.
Another method is to retreat into doubletalk about hyperspace. Doubletalk drives are common enough. The problem is that when everything is permitted, nothing is forbidden. Good stories are made when there are difficulties to overcome, and if there are no limits to "hyper-space travel" there are no real limits to what the heroes and villains can do. In a single work the "difficulties" can be planned as the story goes along, and the drive then redesigned in rewrite; but we couldn't do that here.
Our method was to work out the Drive in detail and live with the resulting limitations. As it happens, the limits on the Drive influenced the final outcome of the story; but they were not invented for that purpose.
The Alderson Drive is consistent with everything presently known about physics. It merely assumes that additional discoveries will be made in about thirty years, at Cal Tech (as a tip o' the hat to Dan Alderson). The key event is the detection of a "fifth force."
There are four known forces in modern physics: two sub-nuclear forces responsible respectively for alpha and beta decay, electromagnetism, which includes light; and gravity. The Alderson force, then, is the fifth, and it is generated by thermonuclear reactions.
The force has little effect in our universe; in fact, it is barely detectable. Simultaneously with the discovery of the fifth force, however, we postulate the discovery of a second universe in point-to-point congruence with our own. The "continuum universe" differs from the one we're used to in that there are no known quantum effects there.
Within that universe particles may travel as fast as they can be accelerated; and the fifth force exists to accelerate them.
There's a lot more, including a page or so of differential equations, but that's the general idea.
You can get from one universe to another. For every construct in our universe there can be created a "correspondence particle" in the continuum universe. In order for your construct to go into and emerge from the continuum universe without change you must have some complex machinery to hold everything together and prevent your ship—and crew—from being disorganized into elementary particles.
Correspondence particles can be boosted to speeds faster than light: in fact, to speeds nearly infinite as we measure them. Of course they cannot emerge into our universe at such speeds: they have to lose their energy to emerge at all. More on that in a moment.
There are severe conditions to entering and leaving the continuum universe. To emerge from the continuum universe you must exit with precisely the same potential energy (measured in terms of the fifth force, not gravity) as you entered. You must also have zero kinetic energy relative to a complex set of coordinates that we won't discuss here.
The fifth force is created by thermonuclear reactions: generally, that is, in stars. You may travel by using it, but only along precisely defined lines of equipotential flux:
tramways
or tramlines.
Imagine the universe as a thin rubber sheet, very flat. Now drop heavy rocks of different weights onto it. The rocks will distort the sheet, making little cone-shaped (more or less) dimples. Now put two rocks reasonably close together: the dimples will intersect in a valley. The intersection will have a "pass," a region higher than the low points where the rocks (stars) lie, but lower than the general level of the rubber sheet.
The route from one star to another through that "pass" is the tramline. Possible tramlines lie between each two stars, but they don't always exist, because when you add third and fourth stars to the system they may interfere, so there is no unique gradient line. If this seems confusing, don't spend a lot of time worrying about it; we'll get to the effects of all this in a moment.
You may also imagine stars to be like hills; move another star close and the hills will intersect. Again, from summit to summit there will be one and only one line that preserves the maximum potential energy for that level. Release a marble on one hill and it will roll down, across the saddle, and up the side of the other. That too is a tramline effect. It's generally easier to think of the system as valleys rather than hills, because to travel from star to star you have to get over that "hump" between the two. The fifth force provides the energy for that.
You enter from the quantum universe. When you travel in the continuum universe you continually lose kinetic energy; it "leaks." This can be detected in our universe as photons. The effect can be important during a space battle. We cut such a space battle from MOTE, but it still exists, and we may yet publish it as a novella.
To get from the quantum to the continuum universe you must supply power, and this is available only in quantum terms. When you do this you turn yourself into a correspondence particle; go across the tramline; and come out at the point on the other side where your potential energy is equal to what you entered with, plus zero kinetic energy—in terms of the fifth force and complex reference axes).
For those bored by the last few paragraphs, take heart: we'll leave the technical details and get on with what it all means.
Travel by Alderson Drive consists of getting to the proper Alderson Point and turning on the Drive. Energy is used. You vanish, to reappear in an immeasurably short time at the Alderson Point in another star system some several light years away. If you haven't done everything right, or aren't at the Alderson Point, you turn on your drive and a lot of energy vanishes. You don't move. (In fact you do move, but you instantaneously reappear in the spot where you started.)
That's all there is to the Drive, but it dictates the structure of an interstellar civilization.
To begin with, the Drive works only from point to point across interstellar distances. Once in a star system you must rely on reaction drives to get around. There's no magic way from, say, Saturn to Earth: you've got to slog across.
Thus space battles are possible, and you can't escape battle by vanishing into hyperspace, as you could in future history series such as Beam Piper's and Gordon Dickson's. To reach a given planet you must travel across its stellar system, and you must enter that system at one of the Alderson Points. There won't be more than five or six possible points of entry, and there may only be one.
Star systems and planets can be thought of as continents and islands, then, and Alderson Points as narrow sea gates such as Suez, Gibraltar, Panama, Malay Straits, etc. To carry the analogy further, there's telegraph but no radio: the fastest message between star systems is one carried by a ship, but within star systems messages go much faster than the ships. . .
Hmm. This sounds a bit like the early days of steam. NOT sail; the ships require fuel and sophisticated repair facilities. They won't pull into some deserted star system and rebuild themselves unless they've carried the spare parts along. However, if you think of naval actions in the periods between the Crimean War and World War One, you'll have a fair picture of conditions as implied by the Alderson Drive.
The Drive's limits mean that uninteresting stellar systems won't be explored. There are too many of them. They may be used as crossing-points if the stars are conveniently placed, but stars not along a travel route may never be visited.
Reaching the Mote, or leaving it, would be damned inconvenient. Its only tramline reaches to a star only a third of a light year
away—
Murcheson's Eye, the red supergiant—and ends deep inside the red-hot outer envelope. The aliens' only access to the Empire is across thirty-five light years of interstellar space—which no Empire ship would ever see. The gaps between the stars are as mysterious to the Empire as they are to you.
Langston Field
Our second key technological building block was the Langston Field, which absorbs and stores energy in proportion to the fourth power of incoming particle energy: that is, a slow-moving object can penetrate it, but the faster it's moving (or hotter it is) the more readily it is absorbed.
(In fact it's not a simple fourth-power equation; but perhaps you don't need third-order differential equations for amusement.)
The Field can be used for protection against lasers, thermonuclear weapons, and nearly anything else. It isn't a perfect defense, however. The natural shape of the Field is a solid. Thus it wants to collapse and vaporize everything inside it. It takes energy to maintain a hole inside the Field, and more energy to open a control in it so that you can cause it selectively to radiate away stored energy. You don't get something for nothing.
This means that if a Field is overloaded, the ship inside vanishes into vapor. In addition,
parts
of the Field can be momentarily overloaded: a sufficiently high energy impacting a small enough area will cause a temporary Field collapse, and a burst of energy penetrates to the inside. This can damage a ship without destroying it.
Cosmography
We've got to invent a term. What is a good word to mean the equivalent of "geography" as projected into interstellar space? True, planetologists have now adopted "geology" to mean geophysical sciences applied to any planet, not merely Earth; and one might reasonably expect "geography" to be applied to the study of physical features of other planets—but we're concerned here with the relationship of star systems to each other.
We suggest cosmography, but perhaps that's too broad? Should that term be used for relationships of
galaxies,
and mere star system patterns be studied as "astrography"? After all, "astrogator" is a widely used term meaning "navigator" for interstellar flight.
Some of the astrography of MOTE was given because it had been previously published. In particular, the New Caledonia system, and the red supergiant known as Murcheson's Eye, had already been worked out. There were also published references to the history of New Caledonia.
We needed a red supergiant in the Empire. There's only one logical place for that, and previously published stories had placed one there: Murcheson's Eye, behind the Coal Sack. It
has
to be behind the Coal Sack: if there were a supergiant that close anywhere else, we'd see it now.
Since we had to use Murcheson's Eye, we had to use New Caledonia. Not that this was any great imposition: New Scotland and New Ireland are interesting places, terraformed planets, with interesting features and interesting cultures.
There was one problem, though: New Scotland is inhabited by New Scots, a people who have preserved their sub-culture for a long time and defend it proudly. Thus, since much of the action takes place on New Scotland, some of the characters, including at least one major character,
had
to be New Scot For structural reasons we had only two choices: the First Officer or the Chief Engineer.
We chose the Chief Engineer, largely because in the contemporary world it is a fact that a vastly disproportionate number of ship's engineers are Scots, and that seemed a reasonable thing to project into the future.
Alas, some critics have resented that, and a few have accused us of stealing Mr. Sinclair from
Star Trek.
We didn't. Mr. Sinclair is what he is for perfectly sound astrographical reasons.
The astrography eventually dictated the title of the book. Since most of the action takes place very near the Coal Sack we needed to know how the Coal Sack would look close up from the back side. Eventually we put swirls of interplanetary dust in it, and evolving proto-stars, and all manner of marvels; but those came after we got
very
close. The first problem was the Coal Sack seen from ten parsecs.
Larry Niven hit on the happy image of a hooded man, with the super-giant where one eye might be. The super-giant has a small companion, a yellow dwarf not very different from our Sun. If the supergiant is an eye—Murcheson's Eye—then the dwarf is, of course, a mote in that eye.
But if the Hooded Man is seen by backward and superstitious peoples as the Face of God. . . then the name for the Mote becomes inevitable. . . and once suggested, The Mote In God's Eye is a near irresistible title. (Although in fact Larry Niven did resist it, and wanted "The Mote In Murcheson's Eye" up to the moment when the publisher argued strongly for the present title. . .)
The Ships
Long ago we acquired a commercial model called "The Explorer Ship Leif Ericson," a plastic spaceship of intriguing design. It is shaped something like a flattened pint whiskey bottle with a long neck The "Leif Ericson," alas, was killed by general lack of interest in spacecraft by model buyers; a ghost of it is still marketed in hideous glow-in-the-dark color as some kind of flying saucer.
It's often easier to take a detailed construct and work within its limits than it is to have too much flexibility. For fun we tried to make the Leif Ericson work as a model for an Empire naval vessel. The exercise proved instructive.
First, the model is of a
big
ship, too poorly designed in shape ever to be carried aboard another vessel. Second, it had fins. Fins are only useful for atmosphere flight: what purpose would be served in having atmosphere capabilities on a large ship?