"Niven, Larry - The Theory And Practice Of Teleportation" - читать интересную книгу автора (Niven Larry)

I


THE ASSUMPTION: We don't need a transmitter. Our teleport receiver will bring anything to itself, from anywhere. Limitations may exist as to distance or mass of cargo.
THE RESULT: Thieves capable of stealing anything from anyone in perfect safety. Such machinery was discovered by Seaton, and later by DuQuesne, in THE SKYLARK OF SPACE. In practice, anyone who has such machinery is king of the world. If many men have transmitterless receivers, society falls apart. When society stops making parts for the machines, the machines fall apart, and everything starts over.


II


THE ASSUMPTION: No receiver is needed. Our teleport transmitter will place its cargo anywhere we choose.
THE RESULT: We can put a bomb anywhere. The idea was used at least once, in THE PERSON FROM PORLOCK. In practice, a government that owned one of these would-again-own the world. Two such governments would probably bomb each other back to a preteleport level of civilization. Presumably it could happen any number of times.


III

Given the assumptions in (I) and (II) you don't really get a society. You get a short war. Hence most stories assume that teleportation requires both a transmitter and a receiver.
Let's do the same. Let us further assume that transmitters (transceivers?) look like telephone booths. You walk into a booth, you put a coin in the slot, you dial. You're elsewhere.
How do they work? We assume either space-bending or the tunnel diode effect. We assume the operation is relatively cheap: no more than a few quarters in the slot. Finally, a slug in the slot will send the customer straight to police headquarters.
THE RESULT: All present transportation becomes obsolete: cars and trucks and freeways, ships and docks, airliners and airports, trains and train stations. What do we do with a continental net of freeways once the cars and busses have disappeared? You use them for drag races and bicycle riding; you put houses on them or turn them into parks. Or you pack them with cars because there's no place else to put the damn useless cars. Not only freeways and turnpikes, but streets and roads and even sidewalks become obsolete. In business districts you keep the sidewalks for window shopping.
Elsewhere, pfftt!
The mind boggles. Assume the population problem continues in the direction it's going. Then, as Isaac Asimov has suggested, new generations could grow up without seeing the exterior of any building, including their own homes. There might soon be no countryside to see in any case, and precious few exteriors to buildings. Without need for streets or sidewalks, there would be no- space between buildings; they would be built wall to wall, or in units a mile cubic. And the people get their exercise by riding bicycles between two open booths arranged like E and F in Figure I.


IV

But suppose there are limitations on the booths? For each assumed limitation one gets a different society.
Let's take a few examples.
THE ASSUMPTION: Booths are expensive to operate.The price for any jump, regardless of distance, is two hundred dollars. (A reasonable restriction. Any spacestressing operation might well cost as much as any other. Ditto for a single tunnel-diode operation.)
THE RESULT: Cars, motor scooters, busses will remain. Except for emergencies, nobody would use booths for distances shorter than a transcontinental flight. But airplanes would disappear, except perhaps for cargo flights.
Change the price and you change the result. As price goes down, freight traffic by train and truck dwindles, and then. even automobiles begin to go. Raise the price to a few thousand dollars, and only spacecraft disappear.
THE ASSUMPTION: The booths are cheap, a couple of bucks a jump, but limited as to distance. Ten miles, let us say, is the upper limit.
THE RESULT: A traveler would move in "hops", naturally. But there would come a point where an airplane is cheaper and more convenient, or both, than a succession of teleport booths. Thus, cars would go, but airplanes and shipping would remain.
Change the limiting distance and, again, you change the society. At a mile a jump only the cars go. At a thousand miles a jump, only spacecraft remain.
THE ASSUMPTION: Teleportation is limited by the Laws of Conservation of energy and Momentum.
THE RESULT: Not very different from above. Cars would go, airplanes would remain. By teleportation we could not travel long distance north and south; we would have to do it on short hops. The longer the hop, the harder momentum would jerk the passenger sideways each time.
Traveling east, our momentum would lift us a few inches from the chair of the receiver booth on each hop. (Yes, I said chair. You might try it standing up, but I wouldn't.) Traveling west would be worse: momentum would slam you down hard. A New Yorker might prefer to reach San Francisco via the western route, in a line of booths crossing the Atlantic and Pacific Oceans.

(Assume a passenger is at the equator, teleporting straight east a distance of X miles.
Then X/4000 is the angle $ of his jump in radians. For X small, we take sine$=$ and get:
X *1000/4000=X/4 [We multiplied the sine of the angle, equal to the angle itself for small angles given in radians, by the rotational velocity of the Earth.]
X/4 is the velocity at which the passenger gets lifted off his feet. Going west, he gets slammed down, same equation. For small angles, the equation holds elsewhere than at the equator. Decreasing the distance from the Earth's axis of rotation decreases the speed of rotation, but increases the angle of shift.)

Notice one important exception. We can travel from the northern hemisphere to the southern in perfect comfort, provided the departure point and destination are at corresponding latitudes.
Elevators become more important than ever. In Earth's gravitational field, at ground level, we lose-seven degrees Fahrenheit for every mile we teleport upward and we gain as much going downhill. Elevators are more comfortable.
So: you want to go skiing in the Swiss Alps, at St. Moritz. From the United States your best bet is to take a plane to someplace with a big landing field, ride an elevator half a mile up to a teleportation booth, then teleport to St. Moritz. Do it any other way and you wind up sick for a couple of days. But from New York you can reach Angol, Chile in one jump!

So much for booths. They still look like our best attempt at prophecy; but let's try some wilder ideas and see what we get.