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

THE ASSUMPTION: Open teleport discs. You step on a disc, it teleports you to another disc. Cost, pennies per thousand trips.
THE RESULTS: All present transportation disappears. With the proper setup, you can walk anywhere on the planet. Figure 2 is a design for intercity transportation, but it can easily be adapted for longer distances. The blocks shown could be lines of longitude and latitude; their length is optional.


For the rectangular city layout shown, we simply walk in the direction we wish to go. The distance between the receiver plate, at the center of the intersection, and the next transmitter disc is about three paces. In three paces one covers a block, whose length, I repeat, is optional. Perhaps there would be faster lanes through the center of town, and faster still between towns: intersections a mile or ten miles apart. To get out of the system one walks around the final disc and goes window shopping or whatever.
The biggest advantage is that we can give up all the endless dialing!
THE ASSUMPTION: Our transmitter is hand sized. We can hang it from our belt. It has (oh, well) a telephone-type dial on it. The receiver is bigger: an open platform, either a small plate at home, in vestibule, or a community receiver the size of a public square. Cost is equivalent to the cost of using a telephone. There are (if necessary) compensators for momentum-and heat-transfer in the receiver plates.
THE RESULT: Bester's THE STARS MY DESTINATION, with minor changes. No mazes behind the doors; simply unlisted receiver numbers.


VI


Shall we design a few spacecraft? Limited teleportation might not make spacecraft obsolete. It might even be used to improve the spacecraft themselves.
THE ASSUMPTIONS: Teleportation requires both a transmitter and a receiver. Conservation holds. Teleportation is instantaneous, and does not involve beaming.
THE RESULT: See Figure 3. The ship consists mainly of a couple of rocket motors, fuel tanks, and an open-ended teleportation receiver open to the rear. You can leave it open because, in vacuum, you don't need to worry about air getting in the receiver.


The ship, unmanned, is fired from Earth orbit or from further out. Probably it should be fired in the direction of the galactic core, where we anticipate more traffic. By firing the ship from, say, Jupiter orbit, we can pack quite a lot of fuel-water, for reaction mass-outside the ship. (See Isaac Asimov, THE MARTIAN WAY.)
We use all the fuel except a reserve for steering. The ship coasts.
It passes through a star system. Let it be about the size of the solar system; then we have ten hours (assuming our ship is near lightspeed) to shove an entire prefab colony into the Earth-based transmitter. If all ten hours are used, then the colony building materials are strewn across the entire system. Each piece of equipment arrives at rest with respect to Earth, and thus leaves the receiver at a speed approaching lightspeed. (Now you know why we put a hole in the receiver.)
Last through the receiver are the ships designed to collect all this crap. Since they are manned, we had better not send them from Earth. Conservation of energy would freeze the pilots to ice in an instant. Consider the irony: to keep them from freezing, we must ship them from Pluto orbit!
It might be more efficient to send through the teleport system only a few ships and another prefab teleport receiver. The rest of the colony comes through the second receiver.
In any case, notice four advantages. You don't have to carry the entire cargo, or waste fuel accelerating it. You don't decelerate the ship, so none of your limited fuel supply need be reserved for that purpose.
The colonists need not twiddle their thumbs for decades. And the ship can be re-used.
Can and will. You just let it coast. Every time it comes near a star system, you have another colony. In eighty thousand years we leave a line of colonies clear across the galaxy, before we finally run out of stars.
Less peaceful societies would shove war fleets through the teleport system. It is hard to imagine a safer way to make war. The fleet is strewn all across the system, with all the warships at rest with respect to the universe at large. And how could the target system counterattack? To reach the invading system, they would have to catch a ship which has had years to accelerate to its tremendous velocity, and which is long gone into interstellar space before the attack can even begin.
During the Boston speech, a member of the audience suggested that teleportation be used to fuel the above craft. Specifically: the motor is a receiver, Open, with a flared nozzle attached. We drop a transmitter on Jupiter. Presto! Hellishly dense high-pressure gas expands explosively into the vacuum of space, driving the ship forward. Fuel supply: inefficient compared to ion drives or the like, but almost literally unlimited.
It won't work. Rather, it won't work for long. Remember, we have assumed that conservation holds.
The motor's exhaust velocity is the ship's own limiting velocity if we use teleportation to fuel the ship. Jupiter's atmosphere wouldn't expand fast enough to be useful. Even with a fusion drive, we lose momentum every time a droplet of hydrogen reaches the fuel tank. We have to get it back by firing the droplet through the rocket motor. When the two velocities balance. . . we can't go any faster.
Total conversion of matter to light does give us unlimited velocity. Then we have only the problem of what to do with the incoming fuel. We always have that problem. A droplet of hydrogen moving at a tenth of lightspeed would vaporize any fuel tank we can build today. Maybe in the future . . . with new materials. . . plenty of padding. . . springs...

Let's try something else.
THE ASSUMPTIONS: The distance one can teleport is relatively restricted. The greater the curvature of space-that is, the greater the proximity to a large mass-the shorter is the limiting distance.
We will assume that on Earth the limiting distance is two feet; around Mars's orbit, some miles; between stars, a few light minutes. Attempt to send a mass beyond the limiting distance, and it will emerge from the receiver as a fluid or a fine dust. The curvature of space distorts the relationships between atoms too greatly.
Again, we assume the conservation laws hold.
THE RESULTS: Feeble as far as true teleportation is concerned. We can teleport fluids, so fuel tanks disappear except for storage tanks and spacecraft. The best we can do for spacecraft is fuel a booster, with a heavily armored fuel tank, designed to lift spacecraft out of a gravity well at low speed. But we can use the system to build a ship...
See Figure 4 (page 103). We'll call this peculiar object the "end-teleport drive," and we'll say that it teleports itself onto its own front end. I invented it many years ago, but I never had the nerve to write a story about it.


Notice that if you push the button, the ship teleports onto its own front end; but if you hold the button down, it will teleport repeatedly, in a steady stream of images. One jump brings the ship to position 2; but the moment it begins to occupy position 2 it wants to be at position 3; as that image starts to form the ship wants to be at position 4, et cetera. If teleportation is rapid enough we can use it for transportation.
You refuse to believe in my ship? Then think of it as an exercise in speculation. Ridiculous as it may seem, we do get results.
1) Rate-of-travel of the ship is limited only by mechanical difficulties, that is, by the rate of successive teleportation. The end-teleport drive does not affect the ship's kinetic energy. We change only the position. So there is none of this nonsense about relativity.
2) We must assume a mechanical limit on rate-of-travel. Otherwise the ship goes off the edge of the universe.
3) You can take your ffinger off the button. Kinetic energy is teleported along with everything else; and as a perfect image you have free will.
4) The longer the ship is, the faster it will go, with a given rate-of-teleportation. But: the longer the ship is, the greater is the danger of getting too near a large mass. To land on Earth the ship would have to be less than two feet long.
In fact, you can't land it anywhere with the end-teleport drive. As with the inertialess drives in Doe Smith's LENSMAN series, you keep an intrinsic velocity which reappears when the drive goes off. To land the ship anywhere you need either inboard auxiliary rockets, or rocket tugs.
5) What happens if something gets in the way of the ship?
Good question. Many things definitely will. Light, for example.
A light beam crosses interstellar space. Suddenly, for an instant, the end-teleport ship is occupying that space. The ship's walls can't stop it, for the light never encountered the walls. A human eye can stop it if the light reaches that eye in time.