Larry Niven defined "teleportation" as any method of moving from point to point in negligible time.

This used to be a mind-boggling cutting-edge science fiction concept back in the late 1800's, e.g., "Professor Vehr's Electrical Experiment" (24 January 1885 The Argonaut) by Robert Duncan Milne. But in 1965 Gene Roddenberry was developing a new TV series called "Star Trek" and found that landing the crew on an alien planet in some kind of shuttle would blow their entire special effect budget. So he invented the Transporter. One cheap optical effect to "beam" the crew down and they were well into the story by script page two.

So nowadays everybody knows what a transporter is, and the phrase "beam me up Scotty, there are no intelligent life forms here" is part of the popular lexicon. This may or may not be the reason why the concept has become passé in science fiction. Which is a pity because it allows science fiction authors to explore all sorts of deep philosophical questions.

The popular term for matter transmitter back in the day was "transmat". But the word really never caught on. George O. Smith said that if audio is for sonics; radio is for electronics; video is for television signals then transmitting matter is "mateo." That word never caught on either. In Poul Anderson's The Enemy Stars they were called "mattercasters." In Piers Anthony's Cluster series they were called "mattermitters." In Harry Harrison's Matter Transmitter series they are called "transmatters". In Murray Leinster's The Wailing Asteroid they are called "matter transposers", in Walt Richmond and Leigh Richmond's The Lost Millennium they are just "transposers."

But are they possible? Maybe. They are certainly unobtainium, verging on handwavium.

And do read the Future War Stories article on Transporters, Portal Guns, and Teleporters.


      Throughout history—and prehistory—mankind’s lot has always been affected by man’s inventions. With the development of the wheel all the varied forms of transportation began. Just think what the canal did to the English countryside and way of life. Or what the railroad, then the airplane, did to the entire world. Everything has changed; nothing is the same.
     Now think of the changes that will be wrought by another form of transportation. The Matter Transmitter. All you have to do is step through the screen and you are on the other side of the world.
     Or on the Moon.
     Or another planet.
     Or the far side of the galaxy.
     Here—step through.

From ONE STEP FROM EARTH by Harry Harrison (1970)

What Am I?

     Let's suppose we have some method of reading out the contents of a human mind into a computer controlling a robotic body, in such a way that the machine behaves like the person it absorbed. Science fiction readers have encountered this concept many times, but often the stories and articles have been humorous in tone, masking, I think, a discomfort with the idea felt even by the authors. This feeling is sometimes articulated in statements such as: "Regardless of how the copying is done, the end result will be a new person.” “If it is I who am being copied, the copy, though it may think of itself as me, is simply a self-deluded imposter.” “If the copying process destroys the original, then I have been killed. That the copy may then have a good time using my name and my skills is no comfort to my mortal remains.”

     The point of view, which I will call the "Body Identity” position, makes a mockery of many of the supposed advantages of being “mind transferred” to a new body. I believe the objection can and should be overcome by intellectual acceptance of an alternate position I will name “Pattern Identity.” Body identity assumes that a person is defined by the stuff of which a human body is made. Only by maintaining continuity of body stuff can we preserve an individual person. Pattern identity, on the other band, defines the essence of a person, say myself, as the pattern and the process going on in my head, and body, not the machinery supporting that process. If the process is preserved, I am preserved. The rest is mere jelly.

Matter Transmistters

     Matter transmitters have appeared often in science fiction, at least since the invention of facsimile machines in the late 1800s. I raise the idea here only as a thought experiment, to simplify some of the issues in the mind transfer proposal. A facsimile transmitter scans a photograph line by line with a light sensitive photocell, and produces an electric current that varies with the brightness of the scanned point in the picture. The varying electric current is transmitted over wires to a remote location where it controls the brightness of a light bulb in a facsimile reciever. The receiver scans the bulb over photosensitive paper in the same pattern as the transmitter. When this paper is developed, a duplicate of the original photograph is obtained. This device was a boon to newspapers, who were able to get illustrations from remote parts of the country almost instantly, rather than after a period of days by train.

     If pictures, why not solid objects? A matter transmitter might scan an object and identify, then knock out, its atoms or molecules one at a time. The identity of the atoms would be transmitted to a receiver where a duplicate of the original object would be assembled in the same order from a local supply of atoms. The technical problems are mind-boggling, and well beyond anything foreseeable, but the principle is simple to grasp. If solid objects, why not a person? just stick him in the transmitter, turn on the scan, and greet him when he walks from the receiver. But is it really the same person? If the system works well, the duplicate will be indistinguishable from the original in any substantial way. Yet, suppose you fail to turn on the receiver during the transmission process. The transmitter will scan and disassemble the victim, and send an unheard message to the inoperative receiver. The original person will be dead. Doesn’t the process, in fact, kill the original person, whether or not there is an active receiver? Isn’t the duplicate just that—merely a clever imposter? Or suppose two receivers respond to the message from one transmitter. Which, if either, of the two duplicates is the real original?

Pattern Identity

     The body identity position is clear: a matter transmitter is an execution device. You might as well save your money and use a gas chamber, and not be taken in by the phony double gimmick. Pattern identity gives a diiterent perspective. Suppose I step into the transmission chamber. The transmitter scans and disassembles my jelly-like body, but my pattern (me!) moves continuously from the dissolving jelly, through the transmitting beam, and ends up in other jelly at the destination. At no instant was it (I) ever destroyed. The biggest confusion comes from the question of duplicates. It is rooted in all our past experience that one person corresponds to one body. In light of the possibility of matter and mind storage and transmission, this simple, natural, and obvious identification becomes confusing and misleading. Suppose the matter transmitted is connected to two receivers instead of one? After the transfer there will be a copy of you in each one. Surely at least one of them is a mere copy—they can't both be you, right? Wrong!

     Consider the message “I am not jelly.” As I type it it goes from my brain, into the keyboard of my computer, through myriads of electronic circuits and over great amounts of wire, and after countless adventures shows up in bunches of books like the one you’re holding. How many messages were there? I claim it is most useful to think there is only one, despite its massive replication. If I repeat it here: “I am not jelly,” there is still only one message. Only if I change it in a significant manner—“I am not peanut butter”—do we have a second message. And the message is not destroyed until the last written version is lost, and until it fades sufficiently in everybody's memory to be unreconstructable. The message is the information conveyed, not the particular encoding.

     The “pattern and process” that I claim is the real me has the same properties as the message above. Making a momentary copy of my state, whether on tape or in another functional body, doesn’t make two persons. There is a complication because of the “process” aspect; as soon as an instance of a “person message” evolves for a while, it becomes a different person. If two of them are active, they will diverge and become two different people, by my definition. Just how far this differentiation must proceed before you grant the two people unique identities is about as problematical as the question “when does a fetus become a person?” But you wait zero time, then you don’t have a new person. If, in the dual receiver version of the matter transmitter, you allow the two copies to be made and kill one (either one) instantly on reception, the transmitted person still exists in the other copy. All the things that person might have done, and all the thoughts he or she might have thought, are still possible. If, on the other hand, you allow both copies to live their separate lives for a year, and then kill one, you are the murderer of a unique human being. But, if you wait only a short while, they won’t dilter by much, and destruction of one won’t cause too much total loss. This rationale might, for instance, be a comfort in danger if you knew that a tape backup copy of you had been made recently. Because of the divergence, the tape contains not you as you are now, but you as you were: a slightly different person. Still, most of you would be saved should you have a fatal accident, and the loss would be nowhere near as great as without the backup.

     Intellectual acceptance that a secure and recent backup of you exists does not necessarily protect you from an instinctive self-preservation overreaction if faced with imminent death. This is an evolutionary hangover from your one-copy past. It is no more a reflection of reality than fear of flying is an appropriate response to present airline accident rates. Inappropriate intuitions are to be expected when the rules of life are suddenly reversed from historical absolutes.

Soul in Abstraction

     Although we’ve reasoned from strictly reductionistic assumptions about the nature of thought and self, the pattern identity position has clear dualistic implications. Though mind is entirely the consequence of interacting matter, the ability to copy it from one machine or storage medium to another gives it an independence and an identity apart from its machinery. The dualism is especially apparent if we consider some of the variations of encoding possible.

     Some supercomputer designs call for myriads of individual computers interconnected by a network that allows free flow of information among them. An operating system for this arrangement might allow individual processes to migrate from one processor to another in mid-computation, in a kind of juggling act that permits more processes than there are processors. If a human mind is installed in a future machine of this variety, functions originally performed by particular cell assemblies might be encoded in individual processes. The juggling action would ensure that operations occurring in fixed areas in the original brain would move rapidly from place to place within the machine. If the computer is running other programs besides the mind simulation, then the simulation might find itself shuffled into entirely different sets of processors from moment to moment. The thinking process would be uninterrupted, even as its location and physical machinery changed continuously, because the immaterial pattern would keep its continuity.

     A process that is described as a long sequence of steps can sometimes be transformed mathematically into one that arrives at the same conclusion in far fewer operations. As a young boy the famous mathematician Friedrich Gauss was a school smart-aleck. As a diversion, a teacher once set him the problem of adding up all the numbers between 1 and 100. He returned with the correct answer in less than a minute. He had no- ticed that the hundred numbers could be grouped into fifty pairs— 1 + 100, 2 + 99, 3 + 98, 4 + 97, and so on—each pair adding up to 101. Fifty times 101 is 5,050—the answer, found without a lot of tedious addition. Similar speedups are possible in complex processes. So-called optimizing compilers have repertoires of accelerating transformations, some very radical, to streamline programs they translate. The key may be a total reorganization in the order of the computation and the representation of the data. A very powerful class of transformations takes an array of values and combines them in different ways to produce another array. Each final value reflects all the original values, and each original value affects all the results. An operation on a single transformed quantity can substitute for a whole host of operations on the original array, and enormous efficiencies are possible. Analogous transformations in time also work: a sequence of operations is changed into an equivalent one where each new step does a tiny fraction of the work of every one of the original steps. The localized is diffused, and the diffused is localized. A program can quickly be altered beyond recognition by a few mathematical rewrites of this power. Run on a multiprocessor, single events in the original formulation may appear only as correlations between events in remote machines at remote times in the transform. Certain operations that don’t matter in the long run may be skipped altogether. Yet the program is fundamentally unchanged. You know what’s coming. If we thus transform a program that simulates a person, the person remains intact. Soul is in the mathematical equivalence, not in any particular detail of the process. It has a very ethereal character.

The Message is the Medium

     If a mind can survive repeated radical restructurings, infusion into and out of different types of hardware and storage media, and is ultimately a mathematical abstraction, does it require hardware at all? Suppose the message describing a person is written in some static medium, like a book. A superintelligent being or a big computer reading and understanding the message might be able to reason out the future evolution of the encoded person, not only under a particular set of experiences, but also under various alternative circumstances. Existence in the thoughts of a beholder is no more abstract than existence as a transformed person-program described in the previous section, but it does introduce an interesting new twist.

     The superintelligent being has no obligations to model every single detail of the beheld accurately, and may well choose to skip the boring parts, to jump to conclusions that are obvious to it, and to lump together different alternatives it does not choose to distinguish. This looseness in the simulation can also allow some time-reversed action—our superintelligent being may choose a conclusion, then reason backwards, deciding what must have preceded it. Authors of fiction often take such liberties with their characters. The same parsimony of thought applies to the parts of the environment of the contemplated person that are themselves being contemplated. Applied a certain way, this parsimony will effect the evolution of the simulated person and his environment, and may thus be noticeable to him. Note that the subjective feelings of the simulated person are a part of the simulation, and with them the contemplated person feels as real in this implementation as in any other.

     It happens that quantum mechanics describes a world where unobserved events happen in all possible ways (another way of saying no decision is made as to which possibility occurs), and the superposition of all these possibilities itself has observable effects. The connection of this observation with those of the previous paragraph leads us into murky philosophical waters. To get even muddier, seriously consider the title of this section. If the subjective feelings of a person are part of the person-message, and if the evolution of the message is implicit in the message itself, then aren't the future experiences of the person implicit in the message? And wouldn’t this mere mathematical existence feel the same to the person encoded as a more substantial simulation? I don’t think this is mere sophistry, but I’m not prepared to take it any further for now.

Immortality and Impermanence

     Wading back into the shallows, let’s examine a certain dilemma of existence, presently overshadowed by the issue of ersonal death, that will be paramount when practical) immortality is achieved. It’s this: in the long run, survival requires change in directions not of your own choosing. Standards escalate with the growth of the inevitable competitors and predators for each niche. In a kind of cosmic Olympic games, the universe molds its occupants toward its own distant and mysterious specifications. An immortal cannot hope to survive unchanged, only to maintain a limited continuity over the short run. Personal death differs from this inevitability only in its relative abruptness. Viewed on a larger scale we are already immortal, as we have been since the dawn of life. Our genes and our culture pass continuously from one generation to the next, subject only to incremental alterations to meet the continuous demand for new world records in the cosmic games.

     In the very long run the ancestral individual is always doomed, as its heritage is nibbled away to meet short-term demands. It slowly mutates into other forms that could have been reached from a range of starting points— the ultimate in convergent evolution. It's by this reasoning that I conclude that it makes no ultimate difference whether our machines carry forward our heritage on their own, or in partnership with direct transcriptions of ourselves. Assuming long-term survival either way, the end results should be indistinguishable, shaped by the universe and not by ourselves. Since change is inevitable, I think we should embrace rather than retard it. By so doing we improve our day-to-day survival odds, discover interesting surprises sooner, and are more prepared to face any competition. The cost is faster erosion of our present constitution. All development can be interpreted as incremental death and new birth, but some of the fast-lane options make this especially obvious; for instance, the possibility of dropping parts of one’s memory and personality in favor of another’s. Fully exploited, this process results in transient individuals constituted from a communal pool of personality traits. Sexual populations are effective in part because they create new genetic individuals in very much this way. As with sexual reproduction, the memory pool requires dissolution as well as creation to be effective. So personal death is not banished, but it does lose its poignancy because death by submergence into the memory pool is reversible in the short run.

Total Clear-Quill 100% Technobabble

(ed note: Our hero was talked into testing an experimental antigravity spaceship made by an eccentric scientist and winds up on the moon. And several million years in the past, when the moon had an atmosphere and a jungle ecosystem. He befriends "The Mother" which is a kindly furry snake like alien being hunted by killer cyborgs who want to harvest her eggs and genetically engineered them into hideous monsters.

It's a long story.

Anyway the killer cyborgs are trying to capture The Mother by using a matter transmitter.)

      I saw the ghostly bars.
     Seven thin upright pillars of light, ringed about us. Straight bars of pale white radiance. They stood like phantom columns about us, inclosing a space ten yards across. They were not above two inches in diameter. And they were quite transparent, so I could see the green jungle and the yellow wall of thorn-brush quite plainly through them.
     I was not particularly alarmed. In fact, I thought the ghostly pillars only some trick of my vision. I rubbed my eyes, and said rather carelessly to the Mother:
     “Are the spirits building a fence around us? Or is it just my eyes?”
     She lifted her golden, blue-crested head quickly. Her violet eyes went wide. I saw alarm in them. Terror. And she moved with astonishing speed. Drew her slender length into a coil. Leaped. And seized my shoulder as she leaped, with one of her mantles.
     She jerked me between two of those strange columns of motionless light, out of the area they enclosed.
     I fell on the sand, got quickly to my feet.
     “What—” I began.
     “The Eternal Ones,” her sweet, whistling tones came swiftly. “They have found me. Even here, they reach me with their evil power. We must go on, quickly.”

(ed note: Our Hero and The Mother are cornered on a hill, surrounded by carnivorous red sphere-like animals.)

     It was late on the following afternoon that I used my last shot. I turned to the Mother with the news that I could no longer keep the red spheres from the walls, that they would soon be overwhelming us.
     “It does not matter,” she piped. “The Eternal Ones have found us again.”

     Looking nervously about, I saw the bars of ghostly light once more. Seven thin upright pillars of silvery radiance, standing in a ring about us. They had exactly the same appearance as those from which we had fled at the pool.
     “I have felt them watching for some time,” she said. “Before, we escaped by running away. Now that is impossible.”
     Calmly she coiled her tawny length. The white mantles were folded against her golden fur. Her small head sank upon her coils, blue crest erect above it. Her violet eyes were grave, calm, alert. They reflected neither fear nor despair.

     The seven pillars of light about us became continually brighter.

     One of the red spheres, with black tentacles extended, dragged itself upon the top of the butte, with us. The Mother saw it, but paid it no heed. It was outside the ring formed by the seven pillars. I stood still, within that ring, beside the Mother, watching—waiting.
     The seven columns of light grew brighter.
     Then it seemed that they were no longer merely light, but solid metal.

     At the same instant, I was blinded with a flash of light, intolerably bright. A splintering crash of sound smote my ears, sharp as the crack of a rifle, infinitely louder. A wave of pain flashed over my body, as if I had received a severe electric shock. I had a sense of abrupt movement, as if the rock beneath my feet had been jarred by a moonquake.
     Then we were no longer upon the rock.

     I was standing upon a broad, smooth metal plate. About its edge rose seven metal rods, shining with a white light, their positions corresponding exactly to the seven ghostly pillars. The Mother was coiled on the metal plate beside me, her violet eyes still cool and quiet, revealing no surprise.
     But I was dazed with astonishment.
     For we were no longer in the jungle. The metal plate upon which I stood was part of a complex mechanism, of bars and coils of shining wire, and huge tubes of transparent, crystal, which stood in the center of a broad open court, paved with bright, worn metal.
     About the court towered buildings. Lofty, rectangular edifices of metal and transparent crystal. They were not beautiful structures. Nor were they in good repair. The metal was covered with ugly red oxide. Many of the crystal panels were shattered.
     Along the metal-paved streets, and on the wide courtyard about us, things were moving. Not human beings. Not evidently, living things at all. But grotesque things of metal. Machines. They had no common standard of form; few seemed to resemble any others. They had apparently been designed with a variety of shapes, to fill a variety of purposes. But many had a semblance to living things that was horrible mockery.
     “This is the land of the Eternal Ones,” the Mother piped to me softly. “These are the beings that destroyed my people, seeking new brains for their wornout machines.”
     “But how did we get here?” I demanded.

     “Evidently they have developed means of transmitting matter through space. A mere technical question. Resolving matter into energy, transmitting the energy without loss on a light beam, condensing it again into the original atoms.
     “It is not remarkable that the Eternal Ones can do such things. When they gave up all that is life, for such power. When they sacrificed their bodies for machines. Should they not have some reward?”
     “It seems impossible—”
     “It must, to you. The science of your world is young. If you have television after a few hundred years, what will you not have developed after a hundred thousand?
     “Even to the Eternal Ones, it is new. It is only in the time of my own life that they have been able to transmit objects between two stations, without destroying their identity. And they have never before used this apparatus, with carrier rays that could reach out to disintegrate our bodies upon the rock, and create a reflecting zone of interference that would focus the beam here—”

From THE MOON ERA by Jack Williamson (1932)


As with all fringe science fiction speculations, if you are going to go beyond physics as we know it, a wise SF author will try to limit the damage. Break one law of physic, not five or six. Try to keep the rest intact.

Conservation Of Energy

Assume that matter transmission obeys the law of conservation of energy. So if you use a transmat to teleport uphill, the transmat will need a way of using extra electricity to compensate for the gravitational potential energy difference or your body will suffer a sudden drop in temperature or other energy loss. Moving uphill creates a gain in potential energy, the law of conservation of energy says that energy has to come from somewhere.

Teleporting downhill means you will lose potential energy. If the transmat does not compensate for it, your body temperature will rise. The energy has to go somewhere.

The equations below were derived by me from Larry Niven's The Theory and Practice of Teleportation. They may be incorrect.

How much energy will be required to be added or removed in order to compensate for altitude change teleports?

ΔU = -(m * g * Δh)


ΔU = ± change in energy (Joules) plus for energy added to object, minus for energy removed
m = mass of object teleported (kg) man=68 kg
g = acceleration due to gravity (m/s) Terra=9.81 m/s
Δh = ± change in altitude (m) plus for traveling upwards, minus for traveling downwards

What will be the temperature effect of uncompensated altitude change teleports?

ΔT = -((m * g * Δh) / (m * C))


ΔT = ± change in temperature (°C or K) plus for heating, minus for cooling
m = mass of object teleported (kg) man=68 kg
g = acceleration due to gravity (m/s) Terra=9.81 m/s
Δh = ± change in altitude (m) plus for traveling upwards, minus for traveling downwards
C = specific heat capacity of object (J/kg-K) man≈4,184 J/kg-K (water)

Example: idiot PFC Floyd steps into a transmat and neglects to turn on the altitude compensator. He set the transmat's destination dials to the top of Mount Krumpet, which is exactly one kilometer higher than Floyd's current location. How much is his body temperature going to drop?

ΔT = -((m * g * Δh) / (m * C))
ΔT = -((68 * 98.1 * 1,000) / (68 * 4,184))
ΔT = -(667,080 / 284,512)
ΔT = -2.4°C

A drop of 2.4 degrees is not enough to kill, but Floyd's teeth might chatter momentarily.

If you used an uncompensated transmat to teleport from the International Space Station to Terra's surface (-400 km), your body temperature would rise from it's normal 37°C to about 997°C. Hot enough to melt silver, and certainly hot enough to kill you instantly. A compensated transmat would suck 266,832,000 joules out of your body in order to spare you from that cruel fate.

Actually, according to the Boom Table it only takes 1.42×108 joules to totally vaporize a body, leaving only a skeleton. Energy compensation is important.

Teleporting up to the ISS will make your body temperature fall from 37°C to about -923°C. Which is pretty frigid, since the coldest spot on Terra is about -50°C. This will also kill you instantly.

A reader named Yoel points out that -923°C is about six hundred and fifty degrees below absolute zero, which is impossible. Niven's equation was sort of assuming that the energy needed to make up for the potential energy loss would come from heat. This observation would mean that either the energy would come from somewhere else, or Floyd would materialize at an altitude corresponding to a temperature drop to absolute zero (−273.15°C). The result would depend upon the details of the teleporation method.

Conservation Of Momentum

Assume that matter transmission obeys the law of conservation of momentum. If you are in an automobile speeding along at 80 kilometers per hour, and use a transmat to teleport to a nearby truck stop, you will arrive at the truck stop. Still moving at 80 kph. It will be more or less the same as if you just jumped out of the moving car.

Conservation of momentum will affect you if you are standing on the ground (of a rotating planet).

Imagine you are above the North Pole of Terra looking down. Terra is spinning counter clock wise. You can see that person Alfa standing on the equator in South America is moving in a direction almost ninety degrees away from person Bravo standing on the equator in Africa (due East). If person Alfa teleported to Africa, the vector sum between their personal vector and the vector of the grounds of Africa will be such that they will be thrown up into the air. If they teleport in a Western direction they will be thrown into the ground. Ouch.

Terra spins "faster" at the equator than it does at, say 45° latitude. This means if you teleport north you'll be jerked to the left, and teleporting south will jerk you to the right.

The equations below were derived by me from Larry Niven's The Theory and Practice of Teleportation. They may be incorrect.

Teleporting East or West, how fast will our teleporter be thrown up in the air or slammed into the ground?

upVel = sinRad(deltaEW / (radiusPlanet * cos(latitude))) * (rotVel * cos(latitude))


upVel = ± velocity teleporter is thrown (m/s) plus for up, minus for down
sinRad(x) = sine of x, where x is in Radians
deltaEW = distance teleported East or West (m)
radiusPlanet = radius of the planet (m) Terra=6,371,000 m
cos(x) = cosine of x, where x is in degrees
latitude = geographical latitude of teleporter (degrees)
rotVel = rotational velocity of the planet at the equator (m/s) Terra=464 m/s

Teleporting North or South, how fast will our teleporter be thrown left or right?

leftVel = (rotVel * cos(startLatitude)) - (rotVel * cos(destLatitude))


leftVel = ± velocity teleporter is thrown (m/s) plus for left, minus for right
rotVel = rotational velocity of the planet at the equator (m/s) Terra=464 m/s
startLatitude = geographical latitude of starting position (degrees)
destLatitude = geographical latitude of destination position (degrees)

which is the delta between the rotational velocity at start and rotational velocity at destination. 464 m/s = about 1,650 km/hr


Mark Atwood asks:

Do stargates conserve kinetic and/or gravitational potential energy? If I put half a pair on a planetary surface and the other a few lightsecs away, do I get to jump into steller orbit without paying for the climb out of the gravity well? If the other half is in orbit around said planet, do I get to jump into planetary orbit without having both pay for the climb out of the well and paying for accelerating to orbital velocity.

The numbers get even bigger, if not as immediately apparent, if one half is orbiting insystem 1 AU from the star, and the other half is outsystem in the inner oort of that same star.

And even bigger when one half is a few hundred ly coreward of the other. The gravity well of a galaxy is surprisingly steep, even this far out, when measured over ly distances.

And then there is conservation of the momentum vectors. Depending on what is conserved and how, putting a hole pair in opposite or right angle orbits around something could do… interesting things. Or else demonstrating some conservation laws between momentum and/or energy and/or hidden variables that we dont have or know in the current real world.

Well, now.

There is both a theoretical and a practical answer to that.

The theoretical answer to that is that they do, because, well, conservation of energy and conservation of momentum are the law, belike. Which can occasionally be bent, but never broken.

So in theory, a stargate jump, in conserving those things, will leave you in a great many awkward situations. If, for example, you were to gate from a planetary surface into orbit, you would absolutely not have orbital velocity, and as such would plummet rapidly to your doom. (Or, if you gated to an internal destination in orbit, slamming into the habitat hull at orbital velocity and being reduced to – extremely destructive – squishy pulp.) In a regular interstellar jump, you will arrive with the exact kinetic energy and momentum relative to the destination system that you had before you left (notwithstanding relevant Gravitational Potential Energy {GPE} corrections, which are where it gets complex, although since most gates are at roughly similar depths in stellar gravity wells to a certain extent GPE can be traded for GPE); which is to say, with that of the origin system relative to the destination system included; which is in turn to say, going UNGODLY FAST in a VERY INCONVENIENT DIRECTION.

This is inconvenient, to say the least.

As such, the stargate system goes to a great deal of trouble to ensure that this is prevented from happening. With selective distortions of the shape of the wormhole’s space-time, it’s easy enough to correct this “intrinsic problem”, but conservation won’t be denied and the energy/momentum has to go somewhere. Fortunately, the exigencies of stargate construction mean that it has an entangled kernel, a nice high-mass (relatively, compared to anything likely to be jumped) Kerr-Newman black hole, right there. So in practice, while energy and momentum are conserved, the transaction it’s conserved within includes the gate singularities acting as a K-sink; excess (or deficient) energy/momentum is dumped into (taken from) the spin, etc., of the kernel to keep the books balanced.

(There are limits on how far this can go, in each direction – so there are occasional issues when a lot more traffic is going one way than the other. Most commonly, this is solved by having the stargate pair dial up its internal link when there’s no ship in transit and use it to swap spin between each end. Ultimately, if that won’t solve the problem, there are internal mechanisms that can be used to spin the kernel up or down, but those are energy-expensive, so they try not to use them much. Either way, unbalanced gates have occasional, periodic downtime while they recharge their K-sinks.)

…there are, of course, various clever tricks you can play with this kinetic compensation system, up to and including disabling it entirely, if you have the privileged-access codes for your blue box, but Ring Dynamics don’t give those out to just anybody.

Transmitter And Receiver

In The Theory and Practice of Teleportation, Larry Niven noted some implications about a transmat's requirements for a transmitter or receiver.

If the transmat does not require a transmitter, it can reach out to anything in range and teleport it to the transmat's receiving stage (e.g., Skylark Duquesne by E. E. "Doc" Smith). This turns out to be unreasonably powerful. A kleptomaniac's dream. Whoever owns a transmitterless transmat can steal anything they want. Not just gold, also things like top-secret government documents. If one person has one they are the king of the world, until somebody assassinates them and becomes the new king. If there are several people who have transmitterless transmats, the economy of the world collapses, technological infrastructure decays, and eventually the transmat cannot be repaired. Civilization has to start over from scratch.

If the transmat does not require a receiver, it can send objects out to anywhere it wants. Objects like bombs (e.g., The Person from Porlock by Raymond F. Jones). This also turns out to be unreasonably powerful. You could find the current location of the leader of a nation you disliked and teleport a nuclear warhead on to their lap. Again if there is only one the owner is the king of the world. Until they are assassinated. If there are two the owning nations will bomb each other and the rest of the world into the stone age (or at least into a level of technological decay where the transmats cannot be repaired).

The main way to reduce the effect these two disasters is to postulate some way of protecting certain areas from teleportation. For example, if they cannot operate on a location that is deep enough underground, or surrounded by a magnetic field, or something.

The easiest way to keep transmats from destroying civilization is to mandate that they require both transmitters and receivers. Most science fiction does for that reason. Except for Star Trek, they stop reckless use of transporters by stopping them with deflector shields around starships or magnetic fields around penal colonies to prevent beaming.

"This is the gulag Rura Penthe. There is no stockade. No guard tower. No electronic frontier. Only a magnetic shield prevents beaming. Punishment means exile from prison to the surface. On the surface, nothing can survive. Work well, and you will be treated well. Work badly, and you will die."


The old science fiction writers assumed that two bodies cannot occupy the same place at the same time. So they figured if you used a transmat to transmit yourself to point Charlie, and there was a large rock occupying point Charlie, both you and the rock would be transformed into a huge explosion. Actually material objects are mostly empty space so you'd probably just become an instant fossil inside the rock (or mostly inside the rock). You'd still be dead, either instantly or eventually.

Transmitting into a mass of air will kill you too. Embolisms, the bends, other nasty effects.

If you have proper transmats needing both transmitter and receiver, you'd want the business ends to have enclosed booths. The idea is as you (and the air around you) are being transmatted from transmat Delta to transmat Foxtrot, the volume of air in the booth on transmat Foxtrox is simultaneously being transmatted to transmat Delta. This way both you and the mass of air will be sent into an empty booth full of vacuum. No boom.

Or you could save power by just pumping all the air out of the destination transmat booth. Just make sure you pump out every scrap of air…

Other Limits

The main variables an author can play with are the maximum range between the origin and destination, and the energy cost per use. This mostly impact what conventional forms of transportation are rendered obsolete by transmats. If the cost per use is fixed regardless of distance, and expensive, automobiles and buses will remain but airplanes will vanish. If cost is cheap but range is limited, people will travel by a series of jumps. But eventually you will reach a point where it is cheaper to use an airplane. So automobiles and buses will vanish.

For other limits, recognize that matter transmission is very much like Discontinuous ("teleport-like") faster-than-light drives. So many of the limits of the numerous times of discontinuous drives can be appropriated by the author and applied to their transmats.

Web and Starship

In the wargame Web and Starship (keep in mind this is a paper-and cardboard tabletop game, not a computer game) game designer (the legendary Greg Costikyan) had a clever limitation on matter transmission, used as a method of FTL travel.

The situation starts with two alien races: the Gwynhyfarr (hereafter referred to as "Birds") and the Pereen (hereafter referred to as "Moles"). Each has a totally different type of FTL transport system.

The Birds have FTL starships that can travel anywhere in the universe at will. No special launch or landing sites are required. The trouble is that the starships are expensive to build (i.e., there are not many of them), and each has a limited cargo capacity.

The Moles have FTL matter transmission. It requires both a transmitter and a receiver. Transmission is instantaneous. Unfortunately in order to transmit to a new planet, a receiver unit must by shipped to the planet by a Slower-than-light robot ship. This of course takes years. The advantage of matter transmission is that they have huge cargo capacities. The Moles can move entire armies through a matter transmitter in a matter of hours.

When the Bird Empire and the Mole Empire expanded to the point where their borders contacted each other, war was inevitable, but futile. Both empires wanted to destroy the other and take over the enemy's habitable planets. Unfortunately, due to the limitations of their respective FTL, war was impossible.

Say the Birds want to invade a Mole planet. The Bird starships can go anywhere, so the Birds load up their limited number of starships with the few numbers of solders each ship can carry, and invade the Mole planet. Whereupon the Moles use their matter transmitters to instantly transport in the planetary armies of all the other Mole planets, and the combined Mole armies turn the pathetically small Bird invasion force into a smoking crater.

Say the Moles want to invade a Bird planet. The Moles load a matter transmitter unit into a STL robot ship, aim it at the Bird planet to invade, and wait a few years for it to arrive. Years later, as it approaches the Bird planet, it is noticed by Bird space patrols, who promptly shoot it to pieces.


Until one fine day both the Birds and the Moles notice radio waves being emitted by a small planet set right in between the two empires. A planet called Earth.


Two great civilizations faced each other across the arm. The Gwynhyfarr, proud descendants of an aerial race, roamed the stars in mighty quantum-leap vessels. The Pereen, the children of burrowing animals, linked their worlds together with the Web. The two found each other incomprehensible. Their mathematics were incompatible, their languages based on different principles, their psychologies entirely at variance. They could not live with each other, and yet they must. Neither was sufficiently mighty to conquer its foe.

But more than this: technologies have military implications. The Gwynhyfarr ships could travel light-years in weeks, could dart from star to star and drive deep into enemy territory. They could also carry only small numbers of troops. Transporting even an infantry division required huge ships in large numbers. In a space battle, the Gwynhyfarr had no match. But the Pereen did not travel space.

The Pereen knew how to conquer intervening distance. Two points could be "gated" together, linked so that one object could pass from one point to another without travelling through the intervening space. Once a gate was constructed on a new world, it was linked via other gates to every world in the Pereen hegemony. The Web permitted instantaneous transmission of huge quantities of materiel from one world to another. The Gwynhyfarr might land a division on a Pereen world—but the Web would immediately transmit an army to that world to defeat its enemies.

But to open a gate, the Pereen must transport the necessary machinery to a new world to make the link to the Web. And the Pereen do not understand Gwynhyfarr faster-than-light travel, and have no such system of their own. Instead, sublight Pereen probes must drone their weary way across space-time toward their targets. When a target is reached, a new world can be added to the Web.

But sublight probes are small and defenseless; they cannot be otherwise, because moving anything at sublight speeds from one star to another requires a tremendous investment in energy and time. Only small objects can affordably make the trip. If a Pereen probe enters a Gwynhyfarr world, its fusion flare will almost certainly be enemy starships, and the probe destroyed.

And so, for decades, the two races bided their time in armed hostility, watching each other across the Carina arm. Limited by their technologies and systems of war, neither could defeat the other.

Then came the radio signals from Terra...

From WEB AND STARSHIP GAME MANUAL, Greg Costikyan (1984)

The Warbots

The Second Alakar (Warbot) was used in several conflicts, among them the most noticeable being the Haak Wars of 14696.

The Haak, centipedean creatures from some obscure place in the galactic center, had stretched their empire out in a most curious fashion. Most races preferred to expand in a globe, the center being their planet of origin. The Haak expanded in a straight line thirty light-years across. They had a science of teleportation, which could get a Haak on the outside border of his empire, twenty thousand light-years to the center, in two years. They did not do very much work with spaceships, beyond sending robot probes to land colonization reception booths.

When the first booths of Haak began landing on human planets in the distant Lace pattern, the alarm went out. The Lace Pattern was occupied by a large number of little human and non-human empires, none very large, and because it was four years of travel from the Palaric States, the nearest really organized culture, it never heard much from the main body of civilization, except for wandering ships of Alakars.

In fact, it was not generally known that all those marvelous myths of Antares, and TOSS, and Pale, and so on, were not fairy tales. Few of the Alakars who wandered through the region had ever been anywhere near the Civilization. The entire war, though it dragged on for ten years, was hardly eighth-page news back in Antares.

From THE WARBOTS by Larry Todd (1968)

The Time Mercenaries


(ed note: the Human/Revain alliance is fighting an interstellar war with the Nerne. The latter species has a breeding rate which makes rabbits and cockroaches look like pikers. They use soldier-wave tactics, Nerne life is less than worthless, they store millions of their newborn offspring in vats under suspended animation.)

      His (the Nerne commander) thoughts drifted away from his own problem to the larger one of interstellar conflict. Centuries ago his own species (the Nerne) had evolved a technique of stellar conquest which was well suited to their prodigious powers of reproduction: send in a ship, establish a base and hold it against attack for long enough to get the matter-transmitters in operation. After that it was simple: pour in troops and weapons powerful enough to hold off a space-borne attack. Once you had done that, the planet was yours and troops could keep pouring in until it was literally flooded.
     Understandably, the Revain, with their vastly slower reproductive capacities and limited numbers, could not match this technique. They could not afford the eighty percent casualty rate of interstellar matter-transmission so they had stuck stubbornly to their growing space fleet. The Nerne had only constructed to keep ahead, not to gain a vast lead in ships, but now, with the humans adding their weight, the Nerne would be compelled to increase their own production. The Commodore felt a twinge of unease. How? Where? They would need at least sixty more production sites to meet the allied construction threat and where would they put them? With every vacant space filled with vats, just how and where would they do it? There was no room in orbit; his home worlds had already lost sixty-five percent of their light from the vast conglomeration of orbiting repair shops, construction vessels and factories.
     His thoughts returned to his own position with some bitterness. These human worlds, all twenty-five of them, could have been taken and occupied in a matter of days with the flooding technique.

     On the three habitable planets of system eighteen, the Nerne took routine defensive measures. Target-seeking missiles were boosted into orbit in increasing numbers, ready to leap outward as soon as the presence of enemy vessels triggered their recognition tapes. On mountaintops and other suitable sites repeller weapons and other massive, long-range armaments bared their black snouts in readiness to meet the invader.
     Beyond the range of all these weapons, however, something happened on the Revain flagship. A peculiar device protruded from its surface which for long seconds flickered oddly, then the fleet changed course.
     For the next three days it traversed the entire length of enemy-held worlds and, at carefully timed intervals, the peculiar device flickered.

     The (Human/Revain) fleet did move and let loose with a reply of their own, a carefully timed avalanche of robotically constructed missiles, most of which were no bigger than the human thumb.
     The acutely sensitive instruments of the Nerne perceived their coming and succeeded in accounting for forty percent of them. Force bubbles sprang into existence over cities, vital installations and the inevitable vats, but the missiles were not aimed at these. One by one, and often in twos and threes, the heavy planet-based weapons were knocked out.
     The local (Nerne) command was not unduly concerned since, protected by the bubbles, they could easily send for more. It was, of course, regrettable that a hundred and eighty thousand troops had been left outside, together with a large number of technicians and construction people, but these, too, could be replaced.
     The (Nerne) technicians switched on the reception cubicles in the huge gasometer-like buildings and made ready to receive. The disposal chutes were open, ready for the removal of loss. The technicians were not entirely without feeling, merely hardened by experience. The first twenty or thirty loads would be a mess; they always were.
     Lights came on, indicating contact with the transmitting beams, and then a piping noise announced the transmission of the first loads.
     Transfer was almost instantaneous but this time there was no crackle of reassembly. Instead, smoke crawled out of power boxes and here plastic or metal turned liquid and circuit breakers fused.
     Alarms piped, acrid blue smoke swirled down corridors, and emergency extinguishers went into action.
     Frantic calls went out. "Reception failure. Halt transmission!"
     Transmission was halted but a considerable number of troops and equipment had already been dispatched. Unless repairs could be effected in a very short period, the projected atoms would lose their cohesion and their reassembly would become an impossibility.
     At the reception cubicles, Nerne technicians blinked their orange eyes helplessly. Whole circuits, printed and atomically suggested, had been wiped out of existence—repair would take days.
     It did not take the experts long to discover that the enemy had found some method of distorting the transmission beams (the peculiar device that flickers oddly).
     By this time, however, leaving four heavy ships in orbit over the planet, the (Human/Revain) fleet had moved on to the next Nerne stronghold, where the same process was repeated. This time, however, no attempt was made to transmit or receive. The Nerne took refuge in their force bubbles.
     The pattern of attack was now alarmingly clear to the Nerne High Command. The enemy were virtually immobilizing their bases one by one—bases which they were unable to reinforce by transmission and, worst of all, expansion bases in the process of development.

From THE TIME MERCENARIES by Philip E. High (1968)

Tunnel in the Sky

An auxiliary gate had been set up on the floor, facing gate five and almost under the balcony. Two high steel fences joined the two gates, forming with them an alley as wide as the gates and as long as the space between, about fifteen meters by seventy-five. This pen was packed with humanity moving from the temporary gate toward and through gate five and onto some planet light years away. They poured out of nowhere, for the floor back of the auxiliary gate was bare, hurried like cattle between the two fences, spilled through gate five and were gone. A squad of brawny Mongol policemen, each armed with a staff as tall as himself, was spread out along each fence. They were using their staves to hurry the emigrants and they were not being gentle. Almost underneath Rod one of them prodded an old coolie so hard that he stumbled and fell. The man had been carrying his belongings, his equipment for a new world, in two bundles supported from a pole balanced on his right shoulder.

The old coolie fell to his skinny knees, tried to get up, fell flat. Rod thought sure he would be trampled, but somehow he was on his feet again minus his baggage. He tried to hold his place in the torrent and recover his possessions, but the guard prodded him again and he was forced to move on barehanded. Rod lost sight of him before he had moved five meters.

There were local police outside the fence but they did not interfere. This narrow stretch between the two gates was, for the time, extra-territory; the local police had no jurisdiction. But one of them did seem annoyed at the brutality shown the old man; he put his face to the steel mesh and called out something in lingua terra. The Mongol cop answered savagely in the same simple language, telling the North American what he could do about it, then went back to shoving and shouting and prodding still more briskly.

"If you will turn your attention again to gate five, we will repeat what we said earlier: gate five is on forty-eight hour loan to the Australasian Republic. The temporary gate you see erected below is hyper-folded to a point in central Australia in the Arunta Desert, where this emigration has been mounting in a great encampment for the past several weeks. His Serene Majesty Chairman Fung Chee Mu of the Australasian Republic has informed the Corporation that his government intends to move in excess of two million people in forty-eight hours, a truly impressive figure, more than forty thousand each hour. The target figure for this year for all planetary emigration gates taken together, Emigrants' Gap, Peter the Great, and Witwaters and Gates is only seventy million emigrants or an average of eight thousand per hour. This movement proposes a rate five times as great using only one gate!"

The commentator continued: "Yet when we watch the speed, efficiency and the, uh forthrightness with which they are carrying out this evolution it seems likely that they will achieve their goal. Our own figures show them to be slightly ahead of quota for the first nine hours. During those same nine hours there have been one hundred seven births and eighty-two deaths among the emigrants, the high death rate, of course, being incident to the temporary hazards of the emigration.

"The planet of destination, GO8703IV, to be called henceforth 'Heavenly Mountains' according to Chairman Fung, is classed as a bounty planet and no attempt had been made to colonize it. The Corporation has been assured that the colonists are volunteers." It seemed to Rod that the announcer's tone was ironical. This is understandable when one considers the phenomenal population pressure of the Australasian Republic.

Gate four had been occupied by a moving cargo belt when he had come in; now the belt had crawled away and lost itself in the bowels of the terminal and an emigration party was lining up to go through.

This was no poverty stricken band of refugees chivvied along by police; here each family had its own wagon, long, sweeping, boat-tight Conestogas drawn by three pair teams and housed in sturdy glass canvas square and businesslike Studebakers with steel bodies, high mud-cutter wheels, and pulled by one or two pair teams. The draft animals were Morgans and lordly Clydesdales and jug-headed Missouri mules with strong shoulders and shrewd, suspicious eyes. Dogs trotted between wheels, wagons were piled high with household goods and implements and children, poultry protested the indignities of fate in cages tied on behind, and a little Shetland pony, riderless but carrying his saddle and just a bit too tall to run underneath with the dogs, stayed close to the tailgate of one family's rig.

It occurred to Rod that there probably was no coffee where they were going and might not be for years, since Terra never exported food, on the contrary, food and fissionable metals were almost the only permissible imports; until an Outland colony produced a surplus of one or the other it could expect precious little help from Terra.

It was extremely expensive in terms of uranium to keep an interstellar gate open and the people in this wagon train could expect to be out of commercial touch with Earth until such a time as they had developed surpluses valuable enough in trade to warrant reopening the gate at regular intervals. Until that time they were on their own and must make do with what they could take with them...which made horses more practical than helicopters, picks and shovels more useful than bulldozers. Machinery gets out of order and requires a complex technology to keep it going but good old "hay-burners" keep right on breeding, cropping grass, and pulling loads.

He scrunched down in his seat, trying to see through the gate to guess the cause of the hold up. He could not see well, as the arching canvas of a prairie schooner blocked his view, but it did seem that the gate operator had a phase error; it looked as if the sky was where the ground ought to be. The extra-dimensional distortions necessary to match places on two planets many light years apart were not simply a matter of expenditure of enormous quantities of energy; they were precision problems fussy beyond belief, involving high mathematics and high art—the math was done by machine but the gate operator always had to adjust the last couple of decimal places by prayer and intuition.

In addition to the dozen-odd proper motions of each of the planets involved, motions which could usually be added and canceled out, there was also the rotation of each planet. The problem was to make the last hyper-fold so that the two planets were internally tangent at the points selected as gates, with their axes parallel and their rotations in the same direction.

Theoretically it was possible to match two points in contra-rotation, twisting the insubstantial fabric of space-time in exact step with 'real' motions; practically such a solution was not only terribly wasteful of energy but almost unworkable the ground surface beyond the gate tended to skid away like a slidewalk and tilt at odd angles.

This gate, being merely for Terra surface commuting, was permanently dilated and required no operator, since the two points brought into coincidence were joined by a rigid frame, the solid Earth. Rod showed his commuter's ticket to the electronic monitor and stepped through to Arizona, in company with a crowd of neighbors. The almost solid Earth. The gate robot took into account tidal distortions but could not anticipate minor seismic variables. As Rod stepped through he felt his feet quiver as if to a small earthquake, then the terra was again firma. But he was still in an airlock at sea level pressure. The radiation from massed bodies triggered the mechanism, the lock closed and air pressure dropped. Rod yawned heavily to adjust to the pressure of Grand Canyon plateau, North Rim, less than three quarters that of New Jersey. But despite the fact that he made the change twice a day he found himself rubbing his right ear to get rid of an ear ache.

Rocket ships did not conquer space; they merely challenged it. A rocket leaving Earth at seven miles per second is terribly slow for the vast reaches beyond. Only the Moon is reasonably near, four days, more or less. Mars is thirty-seven weeks away, Saturn a dreary six years, Pluto an impossible half century, by the elliptical orbits possible to rockets.

Ortega's torch ships brought the Solar System within reach. Based on mass conversion, Einstein's deathless e=mc2, they could boost for the entire trip at any acceleration the pilot could stand. At an easy one gravity the inner planets were only hours from Earth, far Pluto only eighteen days. It was a change like that from horseback to jet plane. The shortcoming of this brave new toy was that there was not much anywhere to go. The Solar system, from a human standpoint, is made up of remarkably unattractive real estate—save for lovely Terra herself, lush and green and beautiful. The steel-limbed Jovians enjoy gravity 2.5 times ours and their poisonous air at inhuman pressure keeps them in health. Martians prosper in near vacuum, the rock lizards of Luna do not breathe at all. But these planets are not for men. Men prosper on an oxygen planet close enough to a G-type star for the weather to cycle around the freezing point of water... that is to say, on Earth.

When you are already there why go anywhere? The reason was babies, too many babies. Malthus pointed it out long ago; food increases by arithmetical progression, people increase by geometrical progression. By World War I half the world lived on the edge of starvation; by World War II Earth's population was increasing by 55,000 people every day; before World War III, as early as 1954, the increase had jumped to 100,000 mouths and stomachs per day, 35,000,000 additional people each year...and the population of Terra had climbed well beyond that which its farm lands could support.

The hydrogen, germ, and nerve gas horrors that followed were not truly political. The true meaning was more that of beggars fighting over a crust of bread. The author of Gulliver's Travels sardonically proposed that Irish babies be fattened for English tables; other students urged less drastic ways of curbing population none of which made the slightest difference. Life, all life, has the twin drives to survive and to reproduce. Intelligence is an aimless by-product except as it serves these basic drives. But intelligence can be made to serve the mindless demands of life. Our Galaxy contains in excess of one hundred thousand Earth-type planets, each as warm and motherly to men as sweet Terra. Ortega's torch ships could reach the stars. Mankind could colonize, even as the hungry millions of Europe had crossed the Atlantic and raised more babies in the New World.

Some did...hundreds of thousands. But the entire race, working as a team, cannot build and launch a hundred ships a day, each fit for a thousand colonists, and keep it up day after day, year after year, time without end. Even with the hands and the will (which the race never had) there is not that much steel, aluminum, and uranium in Earth's crust. There is not one hundredth of the necessary amount.

But intelligence can find solutions where there are none. Psychologists once locked an ape in a room, for which they had arranged only four ways of escaping. Then they spied on him to see which of the four he would find.

The ape escaped a fifth way.

Dr. Jesse Evelyn Ramsbotham had not been trying to solve the baby problem; he had been trying to build a time machine.

Progress in physics is achieved by denying the obvious and accepting the impossible. Any nineteenth century physicist could have given unassailable reasons why atom bombs were impossible if his reason were not affronted at the question; any twentieth century physicist could explain why time travel was incompatible with the real world of spacetime. But Ramsbotham began fiddling with the three greatest Einsteinian equations, the two relativity equations for distance and duration and the mass-conversion equation; each contained the velocity of light. "Velocity" is first derivative, the differential of distance with respect to time; he converted those equations into differential equations, then played games with them. He would feed the results to the Rakitiac computer, remote successor to Univac, Eniac and Maniac

But he did not give up. He made a larger model and tried to arrange a dilation, or anomaly (he did not call it a "Gate") which would let him get in and out of the field himself.

When he threw on power, the space between the curving magnetodes of his rig no longer showed the wall beyond, but a steaming jungle. He jumped to the conclusion that this must be a forest of the Carboniferous Period. It had often occurred to him that the difference between space and time might simply be human prejudice, but this was not one of the times; he believed what he wanted to believe. He hurriedly got a pistol and with much bravery and no sense crawled between the magnetodes.

Ten minutes later he was arrested for waving firearms around in Rio de Janeiro's civic botanical gardens. A lack of the Portuguese language increased both his difficulties and the length of time he spent in a tropical pokey, but three days later through the help of the North American consul he was on his way home. He thought and filled notebooks with equations and question marks on the whole trip.

The short cut to the stars had been found.

Ramsbotham's discoveries eliminated the basic cause of war and solved the problem of what to do with all those dimpled babies. A hundred thousand planets were no farther away than the other side of the street.

From TUNNEL IN THE SKY by Robert Heinlein (1955)

Operating Principle

Now the question arises how the heck does the blasted transmat actually work? Be very very careful when picking this. The operating principle generally creates some major unintended consequences.

Tunnel Diode

A tunnel diode is a common electronic component. But its operating principle contains that magic word "Quantum", beloved of writers of technobabble everywhere. Teachers explain how the things work by using a description that is almost, but not quite, 100% totally wrong. They say that electrons enter in one side and come out the other but do not pass through the space between.

Which was close enough to teleportation for science fiction authors.

I only mention this because it was popular in 1970's science fiction and you might run across it (e.g., "The External Triangle" by George O. Smith). Just be aware that it is technobabble.

We Can Rebuild You

With this method, you somehow convert the atoms of the intrepid explorer's body into radio waves (or tachyon beams, or something), beam them to the destination, then somehow convert the radio waves back into matter.

In a variation on this method, a scanner records each atom's type, position, and energy state. The record is sent to the destination. There an assembler uses the record to reconstruct the traveler's body using a stockpile of various chemical elements. In some science fiction stories, the scanning process vaporizes the traveler's body (e.g., Poul Anderson's The Enemy Stars). In others, the scanning process is harmless, so the traveler is actually sending a duplicate while they stay at home (e.g., Frederik Pohl and Jack Williamson's Farthest Star).

All of these methods open up jumbo-sized cans of screaming worms. They have some serious legal, ethical, and philosophical questions.


First off is the interference problem. What if the signal becomes filled with static? What arrives at the destination will probably be quite dead.


Captain Kirk: "Starfleet, do you have them?"

Starfleet: "Enterprise, what we got back didn't live long … fortunately".

From Star Trek: The Motion Picture (1979 )

Soon, troops, vessels, weapons and equipment were pouring through the matter-transmitters in a flood. Not all of it arrived. Transmission of matter was only one hundred percent assured of arrival intact up to ten thousand miles. It diminished by one percent per twenty thousand miles beyond that distance. As the Nerne were transmitting in terms of light-years, their losses were considerable. More often than not, soldiers, ships and weapons were reassembled in the reception chambers in a gruesome conglomeration of plastic, metal and Nerne flesh.

The species took these losses without comment or concern. They were getting twenty percent through and the invasion force was growing hourly.

The technicians switched on the reception cubicles in the huge gasometer-like buildings and made ready to receive. The disposal chutes were open, ready for the removal of loss. The technicians were not entirely without feeling, merely hardened by experience. The first twenty or thirty loads would be a mess; they always were.

From THE TIME MERCENARIES by Philip E. High (1968)

(ed note: Our heroes, the genius electronic engineers of Venus Equilaterial have decided use the newly invented sub-space radio vacuum tube to make a matter transmitter.)

      "Um. Now bring us up-to-date. What have you in mind?"
     "A tube which scans matter, atom by atom, line by line and plane by plane. The matter is removed, atom by atom, and transmitted by a sort of matter bank in the instrument."
     "A what?"
     "Matter bank," said Walt. "We can't transmit the stuff itself. That's out. We can't dissipate the atomic energy or whatever effect we might get. We can establish a balance locally by using the energy release to drive the restorer. According to some initial experiments, it can be done. We take something fairly complex and break it down. We use the energy of destruction to re-create the matter in the bank, or solid block of local stuff. Let it be a mass of stuff if it wants to; at any rate, the signal im­pulses from the breakdown will be transmitted, scanned if you will, and transmitted to a receiver which reverses the process. It scans, and the matter bank is broken down and the object is reconstructed."
     "I hope we can get free and unrestricted transmutation," offered Don. "You can't send a steel spring out and get one back made of copper."
     "I know we can disintegrate matter through a power tube of slight modification, and reintegrate it with another. At the present state of the art, it is a mess."
     "What's the trouble?"
     "Getting a perfect focus. I want it good enough so that we can scan a polished sheet of steel—and it'll come out as slick as the original."
     "Naturally. We'd better get Wes Farrell on the job."
     "Do we have time to go into the old yarn about the guy who listened in and got replicas?" asked Arden.

(ed note: The villainous Kingman of Terra Electric corporation has sworn to destroy the Venus Equilateral company. He is fuming since he has already tried a few times and been roundly defeated. Venus Equilateral won the right to use Terra Electric's sub-space radio vacuum tube under license. As long as VE only uses it to transmit radio messages, not electrical power. VE places an order with TE for a bunch of gauge blocks with which to test the matter transmitter.)

     Kingman looked up and fixed his superintendent with a fishy glance. "Herman, can you guess why the Venus Equilateral crowd would want two dozen gauge blocks?"
     "Sure. We use Johannson blocks all the time."
     "Channing wants twenty-four blocks. All three inches on a side—cubes. Square to within thirty seconds of angle, and each of the six faces optically flat to one-quarter wavelength of cadmium light."
     "Whoosh!" said Horman. "I presume the three-inch dimension must be within a half-wavelength?"
     "They're quite lenient," said Kingman bitterly. "A full wavelength!"
     "Horman grunted. "I suppose the same thing applies?"
     "We're running over thin ice," said Kingman reflectively. "I can't afford to play rough. We'll make up their blocks."
     "But what could you use two dozen gauge blocks for? All the same size."
     "Inspection standards?" asked Kingman.
     "Not unless they're just being difficult. You don't put primary blocks on any production line. You make secondary gauges for production line use and keep a couple of primaries in the check room to try the secondaries on. In fact, you usually have a whole set of gauge blocks to build up to any desired dimension so that you don't have to stock a half-million of different sizes."
     "Nice going. Well, I'm going to make those gauges. It'll take us one long time, too. Johannson blocks aren't the easiest things in the world to make."
     "What would you make secondary standards out of?"
     "We use glass gauges, mostly. They don't dinge or bend when dropped—they go to pieces or not at all. We can't have a bent gauge rejecting production parts, you know, and steel gauges can be bent. Besides, you can grind glass to a half-wavelength of light with ease, but polishing steel is another item entirely."
     "I'm going to call Channing and ask him about glass blocks. It may be that he might use them. Plus the fact that I may get an inkling of the ultimate use. They have no production lines running on Venus Equilateral, have they?"

     Don hung up and then said: "Glass ones might be a good idea. We can check the transmission characteristics optically. I think we can check more, quicker, than by running analysis on steel."
     "Plus the fact that you can get the blocks back after test," grinned Walt. "Once you tear into a steel block to check its insides, you've lost your sample. I don't know any better way to check homogeneity than by optical tests."
     "O.K. Well, four days for glass blocks will do better than a couple of months on steel blocks."

     They found Farrell in one of the blister laboratories, working on a small edition of the power-transmission tubes. He was not dressed in spacesuit, and so they entered the blister and watched him work.
     "Have a little trouble getting the focus to stay sharp through the trace," Wes complained. "I can get focus of atomic proportions—the circle of confusion is about the size of the atom nucleus, I mean—at the axis of the tube. But the deflection of the cone of energy produces aberration, which causes coma at the edges. The corners of an area look fierce."
     "I wonder if mechanical scanning wouldn't work better."
     "Undoubtedly. You don't hope to send life, do you?"
     "It would be nice—but no more fantastic than this thing is now. What's your opinion?"
     Wes loosened a set screw on the main tube anode and set the anode forward a barely perceptible distance. He checked it with a vernier rule and tightened the screw. He made other adjustments on the works of the tube itself, and then motioned outside. They left the blister, Wes closed the airtight, and cracked the valve that let the air out of the blister. He snapped the switch on the outside panel and then leaned back in his chair while the cathode heated.
     "With electrical scanning, you'll have curvature of field with this gadget. That isn't too bad, I suppose, because the restorer will have the same curvature. But you're going to scan three ways, which means correction for the linear distance from the tube as well as the other side deflections and their aberrations. Now if we could scan the gadget mechanically, we'd have absolute flatness of field, perfect focus, and so forth."
     Walt grinned. "Thinking of television again? Look, bright fellows, how do you move an assembly of mechanical parts in quanta of one atomic diameter? They've been looking for that kind of gadget for centuries. Dr. Rowland and his gratings would turn over in their graves with a contrivance that could rule lines one atom apart."
     Wes Farrell grinned. "Looks like I'd better be getting perfect focus with the electrical system here. I hadn't considered the other angle at all, but it looks a lot tougher than I thought."
     He squinted through a wall-mounted telescope at the setup on the inside of the blister. "She's hot," he remarked quietly, and then set to checking the experiment. Fifteen minutes of checking, and making notes, and he turned to the others with a smile. "Not too bad that way," he said.
     "What are you doing?"
     "I've established a rather complex field. In order to correct the aberrations, I've got non-linear focusing fields in the places where they tend to correct for the off-axis aberrations. To correct for the height effect. I'm putting a variable corrector to control the whole cone of energy, stretching it or shortening it according to the needs. I think if I use a longer focal length I'll be able to get the thing running right.
     "That'll lessen the need for correction, too," he added, cracking the blister-intake valve and letting the air hiss into the blister. He opened the door and went inside, and began to adjust the electrodes. "You know," he added over his shoulder, "we've got something here that might bring a few dollars on the side. This matter-bank affair produces clean, clear, and practically pure metal. You might be able to sell some metal that was rated 'pure' and mean it."
     "You mean absolutely, positively, guaranteed, uncontaminated, unadulterated, perfectly chemically pure?" grinned Don.
     "Compared to what 'chemically pure' really means, your selection of adjectives is a masterpiece of understatement," Walt laughed.

     The cabinet stood in the north end of Venus Equilateral but it was not alone. It may even be the record for all times: certainly no other cabinet three by three by five ever had twenty-seven men all standing in a circle awaiting developments. The cabinet at the south end of Venus Equilateral was no less popular, though the number of watchers was less by one. Here, then, were winner and runner-up of inanimate popularity for the ages. The communicator system set in the walls of the two rooms carried sounds from the north room to the south, and those sounds in the south room could be heard in the north room.
     "Ready, Walt?"
     "Right. I am now slipping the block into the cabinet. The door is closed. Have you got the preliminary synchronizing signal in tick?"
     Channing called: "Wait a minute, I'm lagging a whole cycle."
     "Cut your synchronization input and let the thing catch up."
     "O.K. Um-m-m — Now, Walt."
     "Done!" Walt announced. "Don, crack the door so that the rest of us can laugh if it don't work."
     Channing swaggered over and opened the door. He reached inside and took out the—object.
     He held it up.
     "Walt," he said, "what are you giving me?"
     "I presume that you shipped me one of the cubes?"
     "Well, what we got at this end would positively scare the right arm off of a surrealist sculptor."
     "Hang on to it. I'll be right up."
     "Hang on to it?" laughed Don. "I'm afraid to touch it."
     It was three miles from one end of Venus Equilateral to the other and Walt made it in six minutes from the time he stepped into the little runway car to the time he came into the north-end laboratory and looked over Channing's shoulder at the—thing—that stood on the table.
     "Um," he said. "Sort of distorted, isn't it?"
     "Quite," said Don. "This is glass. It was once a three-inch cube of precision, polish, and beauty. It is now a combination of a circular stairway with round corners and a sort of accordion pleat. Hell's bells!"
     "Be not discouraged," gurgled Walt. "No matter what it looks like, we did transmit matter."
     "Walt, we did accomplish something. It wasn't too good. Now let's figure out why this thing seems to have been run over with a fourth dimensional caterpillar-tread truck."
     "Well, I can hazard a guess. The synchronizing circuits were not clamped perfectly. That gives the accordion-pleat effect. The starting of the trace was not made at the same place each time due to slippage. Well have to beef up the synchronization impulse. The circular-staircase effect was probably due to phase distortion."
     "Could be," said Don. "That means we have to beef up the transmission band so it'll carry a higher frequency."
     "A lower impedance with corrective elements?"
     "Might work. Those will have to be matched closely. We're not transmitting on a line, you know. It's sheer transmission-tube stuff from here to there. Well, gang, we've had our fun. Now let's widen the transmission band and beef up the sync. Then we'll try number two."

     Number two was tried the following afternoon. Again, everybody stood around and watched over Don's shoulder as he removed the cube from the cabinet.
     "Nice," he said, doing a little war dance.
     Franks came in puffing, took the cube from Don's fingers, and inspected it. "Not too bad," he said.
     "Not by a jug full. The index of refraction is higher at this edge than at the other. See?" Walt held the cube before a newspaper and they squinted through the glass block.
     "Seems to be. Now why?"
     "Second harmonic distortion, if present, would tend to thin out one side and thicken up the other side. A sine-wave transmission would result in even thickness, but if second harmonic distortion is present, the broad loops at the top create a condition where the average from zero to top is higher than the average from zero to the other peak. Follow?"
     "That would indicate that the distortion was coming in at this end. If both were even, they would cancel."
     "Right. Your scanning at one end is regular—at the other end it is irregular, resulting in non-homogeneity."
     "The corners aren't sharp," objected Arden.
     "That's an easy one. The wavefront isn't sharp either. Instead of clipping sharply at the end of the trace, the signal tapers off. That means higher-frequency response is needed."
     "We need a term. Audio for sonics; radio for electronics; video for television signals—"
     "Mateo," said Arden.
     "Um—sounds sort of silly," Walt grinned.
     "That's because it's strange. Mateo it is," said Don. "Our mateo amplifier needs higher-frequency response in order to follow the square wavefront. Might put a clipper circuit in there, too."
     "I think a clipper and a sharpener will do more than the higher frequency," said Farrell. He was plying a vernier caliper, and he added: "I'm certain of that second harmonic stuff now. The dimension is cockeyed on this side. Tell you what, Don. I'm going to have the index of refraction measured within an inch of its life. Then we'll check the thing and apply some high-powered math and see if we can come up with the percentage of distortion."
     "Go ahead. Meanwhile, we'll apply the harmonic analyzer to this thing and see what we find. If we square up the edges and make her homogeneous, we'll be in business."

(ed note: The evil Kingman thinks he sees his chance to destroy Venus Equilateral. He takes them to court, saying VE violated their contract. His legal theory is that since matter is energy, a matter transmitter is also an energy transmitter. In court, VE has to explain to the technophobe judge how the matter transmitter works.)

     Farrell moistened his lips and said: "Utilizing certain effects noted with earlier experimentation, we have achieved the following effects: the matter to be transmitted is placed in situ, where it is scanned by an atom scanner. This removes the substance, atom by atom, converting the atoms to energy. This energy is then re­converted into atoms and stored in a matter bank as matter again. The energy of disintegration is utilized in reintegration at the matter bank with but small losses. Since some atoms have higher energy than others, the matter bank's composition will depend upon the scanned substance."
     "The matter bank is composed of the same elements as the matter for transmission?" asked Kingman.
     "No. Some elements release more energy than others. It is desirable that the energy transfer be slightly negative. That is to say, that additional energy must be used in order to make the thing work."
     "All power lines and other devices are developed for delivering energy, not receiving it. It is less disastrous to take energy from a power line than to try to drive it back in—and the energy must be dissipated somehow."
     "Then the matter bank is not the same material."
     "No," said Farrell. "The substance of the matter bank is non-homogeneous. Simultaneously, it will be whatever element is necessary to maintain the fine balance of energy—and it is in constant change."
     "Proceed," said Kingman.
     "In passing from the disintegrator tube to the reintegrator tube, the energy impresses its characteristic signal on a sub-ether transmission system. Radio might work, except that the signal is unbelievably complex. Wired communications—"
     "Objection to the term," said Kingman.
     "Wired—transfer—might work, but probably would not, due to this same high complexity in transmitted signal. At any rate, upon reception, the signal is used to influence or modulate the energy passing from a disintegrator tube in the receiver. But this time the tube is tearing down the matter bank and restoring the object. Follow?"

(ed note: during an intermission Keg Johnson asks Don Channing a question)

     Look, Don, have you tried living matter?"
     "Plants go through with no ill effects. Microscopic life does, too. Animals we have tried died because of internal disorders—they move while being scanned, and their bodies come out looking rather ugly. An anaesthetized mouse went through all right—lived for several hours. Died because the breathing function made a microscopic rift in the lungs, and the beating heart didn't quite meet true. We must speed up the scanning time to a matter of microseconds and then we can send living bodies with no harm."

(ed note: VE does a demonstration of their matter transmitter. Kingman objects that it is impossible to tell if a test block was actually transmitted since all test blocks are identical. The judge offers as a test item his expensive and unique pocket watch, since there are only nine like it in the entire solar system. Channing uses it, which in retrospect was a very bad idea.)

     Channing pushed a button. There was a minute, whirring, hum, a crackle of ozone, very faint, and an almost imperceptible wave of heat from both machines. "Now," said Walt Franks, "we'll see." He opened the cabinet and reached in with a flourish.
     His face fell. It turned rosy. He opened his mouth to speak, but nothing but choking sounds came forth. He spluttered, took a deep breath, and then shook his head in slow negation. Slowly, like a boy coming in for a whipping, Walt took out the judge's watch. He handed it to Don.
     Don, knowing from Walt's expression that something was very, very wrong, took the watch gingerly, but quickly. He hated to look and yet was burning with worried curiosity at the same time.
     In all three dimensions the watch had lost its shape. It was no longer a lenticular object, but had a very faint sine wave in its structure. The round case was distorted in this wave, and the face went through the same long swell and ebb as the case. The hands maintained their distance from this wavy face by conforming to the sine-wave contour of the watch. And Channing knew without opening the watch that the insides were all on the sine-wave principle, too. The case wouldn't have opened, Don knew, because it was a screw-on case, and the threads were rippling up and down along with the case and cover. The knurled stem wouldn't have turned, and as Channing shook the watch gently, it gave forth with one—and only one—tick as the slack in the distorted balance wheel went out.
     He faced the judge. "We seem—"
     "You blasted fools and idiots!" roared the judge. "Nine of them!"
     He turned and stiffly went to his seat. Channing returned to the witness chair.
     "How do you explain that?" roared Judge Hamilton.
     "I can only think of one answer," offered Channing in a low voice. "We made the power supplies out of power and voltage transducers and filtered the output for sixty cycles. Buffalo is still using twenty-five-cycle current. Since the reactances of both capacity and inductance vary according to the—"

(ed note: after court ajourns for the day, Don and Walt gets plastered with a bottle of whiskey to try and forget the disaster. Wes Farrell shows up)

     "Look fellows, I'm sorry about that fool mistake. I've been working on the judge's ticker. I've fixed it."
     "Pitched it?" asked Walt, opening his eyes wide.
     "Close 'em—y'll bleed t'death," Don gurgled.
     Farrell dangled the judge's watch before them. It was perfect. It ticked, it ran, and though they couldn't possibly have seen the hands from a distance of more than nine inches, it was keeping perfect time.
     Don shook his head, moaned at the result of the shaking, put both hands on his head to hold it down, and looked again. "How'ja do it?"
     "Made a recording of the transmitted signal. Fixed the power supply filters first. Then took the recording—"
     "On whut?" spluttered Walt.
     "On a disk like the alloy tuners in the communications beams. Worked fine. Anyway, I recorded the signal, and then started to buck out the ripple by adding some out-of-phase hum to cancel the ripple."
     "Shounds reas'n'ble."
     "Worked. I had a couple of messes, though."
     "Messessessesss?" Walt hissed, losing control over his tongue.
     "Yes. Had a bit of trouble making the ripple match." Farrell pulled several watches from his pocket. "This one added ripple. It's quite cockeyed. This one had cross-ripple and it's really a mess. It sort of looks like you feel, Walt. I've got 'em with double ripples, triple ripples, phase distortion, over-correction, and one that reminds me of a pancake run through a frilling machine."
     Channing looked at the collection of scrambled watches and shuddered. "Take 'em away. Brrrrr."

(ed note: And by the end, Venus Equilateral wins again and the evil Kingman goes down in defeat. However, there are unexpected consequences.)

From SPECIAL DELIVERY by George O. Smith (1945)

Things can be much worse, as anybody who saw one of The Fly movies knows. If a fly shares the transmat booth with you, what arrives at the destination can be a man with a fly head and a fly with a human head. Or a gruesome melding of the two.


Next problem, if it cannot be recorded, it cannot be recreated. I don't mean to go all metaphysical on you, but if you have something like a soul it probably ain't gonna be 3D printed at the destination. Which means you will be dead, even though there will be a remarkably realistic soulless replica of you walking out of the transmat booth.


"What worries me," McCoy said, "is whether I'm myself any more. I have a horrible suspicion that I'm a ghost. And that I've been one for maybe as long as twenty years."

The question caught Captain Kirk's ear as he was crossing the rec room of the Enterprise with a handful of coffee. It was not addressed to him, however; turning, he saw that the starship's surgeon was sitting at a table with Scott, who was listening with apparently deep attention. Scotty listening to personal confidences? Or Doc offering them? Ordinarily Scotty had about as much interest in people as his engines might have taken; and McCoy was reticent to the point of cynicism.

"May I join this symposium?" Kirk said. "Or is it private?"

"It's nae private, it's just nonsense, I think," the engineering officer said. "Doc here is developing a notion that the transporter is a sort of electric chair. Thus far, I canna follow him, but I'm trying, I'll do myself that credit."

"Oh," Kirk said, for want of anything else to say. He sat down. His first impression, that McCoy had been obliquely referring to his divorce, was now out the porthole, which both restored his faith in his understanding of McCoy's character, and left him totally at sea.

"Somebody," Kirk said, "had better fill me in. Doc, you've said nine times to the dozen that you don't like the transporter system. In fact, I think 'loath,' is the word you use. 'I do not care to have my molecules scrambled and beamed around as if I were a radio message.' Is this just more of the same?"

"It is and it isn't," McCoy said. "It goes like this. If I understand Scotty aright, the transporter turns our bodies into energy and then reconstitutes them as matter at the destination…"

"That's a turrble oversimplification," Scott objected. The presence of his accent, which came out only under stress, was now explained; they were talking about machinery, with which he was actively in love. "What the transporter does is analyze the energy state of each particle in the body and then produce a Dirac jump to an equivalent state somewhere else. No conversion is involved—if it were, we'd blow up the ship."

"I don't care about that," McCoy said. "What I care about is my state of consciousness—my ego, if you like. And it isn't matter, energy or anything else I can name, despite the fact that it's the central phenomenon of all human thought. After all, we all know we live in a solipsistic universe."

Kirk searched his memory. "But you still haven't answered my question. What's all this got to do with the transporter?"

"Nary a thing," Scott said.

"On the contrary. Whatever the mechanism, the effect of the transporter is to dissolve my body and reassemble it somewhere else. Now you'll agree from experience that this process takes finite, physical time—short, but measurable. Also from experience, that during that time period neither body nor consciousness exists. Okay so far?"

"Well, in a cloudy sort of way," Kirk said.

"Good. Now, at the other end, a body is assembled which is apparently identical with the original, is alive, has consciousness, and has all the memories of the original. But it is NOT the original. That has been destroyed."

"I canna see that it matters a whit," Scott said. "Any more than your solipsist position does. As Mr. Spock is fond of saying, 'A difference which makes no difference is no difference.'"

"No, not to you," McCoy said, "because the new McCoy will look and behave in all respects like the old one. But to me? I can't take so operational a view of the matter. I am, by definition, not the same man who went into a transporter for the first time twenty years ago. I am a construct made by a machine after the image of a dead man—and the hell of it is, not even I can know how exact the imitation is, because—well, because obviously if anything is missing I wouldn't remember it."

"Question," Kirk said. "Do you feel any different?"

"Aha," said Scott with satisfaction.

"No, Jim, I don't, but how could I? I think I remember what I was like before, but in that I may be vastly mistaken. Psychology is my specialty, for all that you see me chiefly as a man reluctant to hand out pills. I know that there are vast areas of my mind that are inaccessible to my consciousness except under special conditions—under stress, say, or in dreams. What if part of that psychic underground has not been duplicated? How would I know?"

"You could ask Spock," Scott suggested.

"Thanks, no. The one time I was in mind-lock with him it saved my life—it saved all of us, you'll remember—but I didn't find it pleasant."

"Well, you ought to, anyhow," Scott said, "if you're as serious about all this. He could lock onto one of those unconscious areas and then see if it was still there after your next transporter trip."

"Which it almost surely would be," Kirk added. "I don't see why you assume the transporter to be so peculiarly selective. Why should it blot out subconscious traces instead of conscious ones?"

"Why shouldn't it? And in point of fact, does it or doesn't it? That's pretty close to the question I want answered. If it were the question, I would even submit to the experiment Scotty proposes, and ask everybody else aboard to as well."

"I," said Kirk, "have been on starship duty somewhat longer than either of you gentlemen. And I will say without qualification that this is the weirdest rec room conversation I've ever gotten into. But all right, Doc, let's bite the bullet. What is the question?"

"What would you expect from a psychologist?" McCoy said. "The question, of course, is the soul. If it exists, which I know no more than the next man. When I was first reassembled by that damnable machine, did my soul, if any, make the crossing with me—or am I just a reasonable automaton?"

"The ability to worry about the question," Kirk said, "seems to me to be its own answer."

"Hmmm. You may be right, Jim. In fact, you better had be. Because if you aren't, then every time we put a man through the transporter for the first time, we commit murder."

"And thot's nae a haggle, it's a haggis," Scott said hotly. "Look ye, Doc, yon soul's immortal by definition. If it exists, it canna be destroyed—"

"Captain Kirk," said the rec room's intercom speaker.

From SPOCK MUST DIE! by James Blish (1970)

(ed note: Southern Cross is a slower-than-light but near-light starship. It has delta-Ved up to half lightspeed, and is now coasting to its destination at Alpha Crucis. This will take several centuries. It is equipped with an FTL matter transmitter, called a "mattercaster". Over the centuries, starship crew has taken turns crewing the ship. From several nations, as nations rise and fall. Traditionally the crews serve one month watches on the starship.)

      ‘How long will you be gone?’ she asked.
     ‘Can’t say for certain, but probably just a month. That ought to furnish me with enough material for several years of study. Might dash back to the ship at odd moments for the rest of my life, of course. It’ll take up permanent residence around that star.’
     ‘Couldn’t you come home … every night?’ she murmured.
     ‘Don’t tempt me,’ he groaned. ‘I can’t. One month is the standard minimum watch on an interstellar vessel, barring emergencies. You see, every transmission uses up a Frank tube, which costs money.’

(ed note: The Terran Protectorate holds tight control over the colony worlds. Many plot revolution, to free themselves from the Terran yoke.)

     The thin man asked, ‘This is the clandestine bomb factory?’
     ‘No,’ said Li-Tsung. ‘It is time you learned of these matters, especially when you are leaving the system today. This man has been helping direct something more important than small-arms manufacture. They are tooling up out there to make interplanetary missiles.’
     ‘What for?’ answered the stranger. ‘Once the Fellowship has seized the mattercaster, it will be years before reinforcements can arrive from any other system. You’ll have time enough to build heavy armament then.’ He glanced inquiringly at Sverdlov. Li-Tsung nodded. ‘In fact,’ said the thin man, ‘my division is trying to so organise things that there will be no closer Protectorate forces than Earth itself. Simultaneous revolution on a dozen planets. Then it would be at least two decades before (slower-than-light) spaceships could reach Tau Ceti.’
     ‘Ah,’ grunted Sverdlov. He lowered his hairy body into a chair. His cigar jabbed at the thin man. ‘Have you ever thought, the Earthlings are no fools? The mattercaster for the Tau Ceti System is up there on Moon Two. Sure. We seize it, or destroy it. But is it the only transceiver around?’
     The thin man choked. Li-Tsung murmured, ‘This is not for the rank and file. There is enough awe of Earth already, to hold the people back. But in point of fact, the Protector is an idiot if there is not at least one asteroid in some unlikely orbit, with a heavy-duty ’caster mounted on it. We can expect the Navy in our skies within hours of the independence proclamation. We must be prepared to fight!’
     ‘But – ’ said the thin man, ‘but this means it will take years more to make ready than I thought. I had hoped – ’
     ‘The Centaurians rebelled prematurely, forty years ago,’ said Li-Tsung. ‘Let us never forget the lesson Do you want to be lobotomised?’

     To make conversation, he said through a tightness, ‘Where are the bulkheads?’
     ‘Which ones?’ asked Maclaren absently.
     ‘Safety bulkheads. A receiver does fail once in a great while, you know. That’s why the installations here are spread out so much, why every star has a separate ‘caster. There’s a vast amount of energy involved in each transmission – one reason why a ’casting is more expensive than transportation by spaceship. Even a small increment, undissipated, can melt a whole chamber.’
     ‘Oh, yes. That.’ Maclaren had let Ryerson get pompous about the obvious because it was plain he needed something to bolster himself. What itched the kid, anyhow? One should think that when the Authority offered a fledgling a post on an expedition as fundamental as this Of course, it had upset Ryerson’s plans of emigration. But not importantly. There was no danger he would find all the choice sites on Rama occupied if he came several weeks late: too few people had the fare as it was.
     Maclaren said, ‘I see what you mean. Yes, the bulkheads are there, but recessed into the walls and camouflaged. You don’t want to emphasise possible danger to the cash customers, eh? Some technic (aristocrat) might get annoyed and make trouble.’
     ‘Some day,’ said Ryerson, ‘they’ll reduce the energy margin needed; and they’ll figure how to reproduce a Frank tube, rather than manufacture it. Record the pattern and recreate from a matter bank. Then anyone can afford to ride the beams. Interplanetary ships, even air and surface craft, will become obsolete.’ (this implies that the starship must have a huge stock of Frank tubes)
     Maclaren made no answer. He had sometimes thought, more or less idly, about the unrealised potentialities of mattercasting. Hard to say whether personal immortality would be a good thing or not. Not for the masses, surely! Too many of them as it was. But a select few, like Terangi Maclaren – or was it worth the trouble? Even given boats, chess, music, the No Drama, beautiful women and beautiful spectroscopes, life could get heavy.
     As for matter transmission, the difficulty and hence the expense lay in the complexity of the signal. Consider an adult human. There are some 1014 cells in him, each an elaborate structure involving many proteins with molecular weights in the millions. You had to scan every one of those molecules identify it structurally, ticket its momentary energy levels, and place it in proper spatiotemporal relationship to every other molecule – as nearly simultaneously as the laws of physics permitted. You couldn’t take a man apart, or reassemble him, in more than a few microseconds; he wouldn’t survive it. You couldn’t even transmit a recognisable beefsteak in much less of a hurry.
     So the scanning beam went through and through, like a blade of energy. It touched every atom in its path, was modified thereby, and flashed that modification on to the transmitter matrix. But such fury destroyed. The scanned object was reduced to gas, so quickly that only an oscilloscope could watch the process. The gas was sucked into the destructor chamber and atomically condensed in the matter bank; in time it would become an incoming passenger, or incoming freight. In a sense, the man had died.
     If you could record the signal which entered the transmitter matrix, you could keep such a record indefinitely, recreate the man and his instantaneous memories, thoughts, habits, prejudices, hopes and loves and hates and horrors, a thousand years afterward. You could create a billion identical men. Or, more practically, a single handmade prototype could become a billion indistinguishable copies; nothing would be worth more than any handful of dirt. Or … superimpose the neurone trace-patterns, memories, of a lifetime, on to a recorded twenty-year-old body, be born again and live forever!
     The signal was too complex, though. An unpromising research program went on. Perhaps in a few centuries they would find some trick which would enable them to record a man, or even a Frank tube. Meanwhile, transmission had to be simultaneous with scanning. The signal went out. Probably it would be relayed a few times. Eventually the desired receiving chamber got it. The receiver matrix, powered by dying atomic nuclei, flung gases together, formed higher elements, formed molecules and cells and dreams according to the signal, in microseconds. It was designed as an energy-consuming process, for obvious reasons: packing fraction energy was dissipated in gravitic and magnetic fields, to help shape the man (or the beefsteak, or the spaceship, or the colonial planet’s produce). He left the receiving chamber and went about his business.
     A mono-isotopic element is a simple enough signal to record, Maclaren reminded himself, though even that requires a houseful of transistor elements. So this civilisation can afford to be extravagant with metals – can use pure mercury as the raw material of a spaceship’s blast, for instance. But we still eat our bread in the sweat of some commoner’s brow.
     Not for the first time, but with no great indignation – life was too short for anything but amusement at the human race – Maclaren wondered if the recording problem really was as difficult as the physicists claimed. No government likes revolutions, and molecular duplication would revolutionise society beyond imagining. Just think how they had to guard the stations as it was, and stick them out here on the Moon … otherwise, even today, some fanatic could steal a tube of radium from a hospital and duplicate enough to sterilise a planet!
     ‘Oh, well,’ he said, half aloud.
     They reached the special exploratory section and entered an office. There was red tape to unsnarl. Ryerson let Maclaren handle it, and spent the time trying to understand that soon the pattern which was himself would be embodied in new shaped atoms, a hundred light-years from Tamara. It wouldn’t penetrate. It was only words.
     Finally the papers were stamped. The transceivers to/from an interstellar spaceship could handle several hundred kilos at a time; Maclaren and Ryerson went together. They had a moment’s wait because of locked safety switches on the Southern Cross: someone else was arriving or departing ahead of them.
     ‘Watch that first step,’ said Maclaren. ‘It’s a honey.’
     ‘What?’ Ryerson blinked at him, uncomprehending.
     The circuit closed. There was no sensation, the process went too fast.
     The scanner put its signal into the matrix. The matrix modulated the carrier wave. But such terminology is mere slang, borrowed from electronics. You cannot have a ‘wave’ when you have no velocity, and gravitational forces do not. (This is a more accurate rendition of the common statement that ‘gravitation propagates at an infinite speed’.) Inconceivable energies surged within a thermonuclear fire chamber; nothing controlled them, nothing could control them, but the force fields they themselves generated. Matter pulsed in and out of existence qua matter, from particle to gamma ray quantum and back. Since quanta have no rest mass, the pulsations disturbed the geometry of space according to the laws of Einsteinian mechanics. Not much: gravitation is feebler than magnetism or electricity. Were it not for the resonance effect, the signal would have been smothered in ‘noise’ a few kilometers away. Even as it was, there were many relayings across the parsecs, until the matrix on the Cross reacted. And yet in one sense no time at all had passed; and no self-respecting mathematician would have called the ‘beam’ by such a name. It was, however, a signal, the only signal which relativity physics allowed to go faster than light – and, after all, it did not really go, it simply was.
     Despite the pill inside him, Ryerson felt as if the bottom had dropped out of the world. He grabbed for a handhold. The after-image of the transmitter chamber yielded to the coils and banks of the receiver room on a spaceship. He hung weightless, a thousand billion billion kilometers from Earth (the Southern Cross has reached a distance of 90 parsecs from Terra, about a hundred light-years).

     ‘Any luck?’ he asked after a while.
     ‘Not yet. I’m trying a new sequence now. Don’t worry, we’re bound to hit resonance soon.’
     Maclaren considered the problem for a while. Lately his mind seemed to have lost as much ability to hold things as his fingers. Painfully, he reconstructed the theory and practice of gravitic mattercasting. Everything followed with simple logic from the fact that it was possible at all.
     The signals necessarily used a pulse code, with amplitude and duration as the variables; there were tricky ways to include a little more information through the number of pulses per millisecond, if you set an upper limit to the duration of each. It all took place so rapidly that engineers could speak in wave terms without too gross an approximation. Each transceiver identified itself by a ‘carrier’ pattern, of which the actual mattercasting signal was a modulation. The process only took place if contact had been established, that is, if the transmitter was emitting the carrier pattern of a functioning receiver: the ‘resonance’ or ‘awareness’ effect which beat the inverse-square law, a development of Einstein’s great truth that the entire cosmos is shaped by what momentarily happens to each of its material parts.
     The ’caster itself, by the very act of scanning, generated the signals which recreated the object transmitted. But first the ’caster must be tuned in on the desired receiving station. The manual aboard ship gave the call pattern of every established transceiver: but, naturally, gave it in terms of the standardised and tested web originally built into the ship. Thus, to reach Sol, the book said, blend its pattern with that of Rashid’s Star, the initial relay station in this particular case. Your signal will be automatically bucked on, through several worlds, till it reaches Earth’s Moon. Here are the respective voltages, oscillator frequencies, etc., involved; add them up and use the resultant.
     Ryerson’s handmade web was not standardised. He could put a known pattern into it, electronically, but the gravitics would emit an unknown one, the call signal of a station not to be built for the next thousand years. He lacked instruments to measure the relationship, so he could not recalculate the appropriate settings. It was cut and try, with a literal infinity of choices and only a few jackleg estimates to rule out some of the possibilities.
     Maclaren sighed. A long time had passed while he sat thinking. Or so his watch claimed. He hadn’t noticed it go by, himself.
     ‘You know something, Dave?’ he said.
     ‘Hm?’ Ryerson turned a knob, slid a vernier one notch, and punched along a row of buttons.
     ‘We are out on the far edge of no place. I forget how far to the nearest station, but a devil of a long ways. This haywire rig of ours may not have the power to reach it.’
     ‘I knew that all the time,’ said Ryerson. He slapped the main switch. Needles wavered on dials, oscilloscope tracings glowed elfhill green, it whined in the air. ‘I think our apparatus is husky enough, though. Remember, this ship has left Sol farther behind than any other ever did. They knew she would – a straight-line course would just naturally outrun the three-dimensional expansion of our territory – so they built the transceiver with capacity to spare. Even in its present battered state, it might reach Sol directly. If conditions were just right.’
     ‘Think we will? That would be fun.’

From THE ENEMY STARS by Poul Anderson ()

There were a lot of things, he told himself, that Man would have to unlearn, as well as things to learn, if he ever should become aware of the galactic culture.

The limitation of the speed of light, for one thing.

For if nothing moved faster than the speed of light, then the galactic transport system would be impossible.

But one should not censure Man, he reminded himself, for setting the speed of light as a basic limitation. Observations were all that Man — or anyone, for that matter — could use as data upon which to base his premises. And since human science had so far found nothing which consistently moved faster than the speed of light, then the assumption must be valid that nothing could or did consistently move faster. But valid as an assumption only and no more than that.

For the impulse patterns which carried creatures star to star were almost instantaneous, no matter what the distance.

He stood and thought about it and it still was hard, he admitted to himself, for a person to believe.

Moments ago the creature in the tank had rested in another tank in another station and the materializer had built up a pattern of it — not only of its body, but of its very vital force, the thing that gave it life. Then the impulse pattern had moved across the gulfs of space almost instantaneously to the receiver of this station, where the pattern had been used to duplicate the body and the mind and memory and the life of that creature now lying dead many light years distant. And in the tank the new body and the new mind and memory and life had taken almost instant form — an entirely new being, but exactly like the old one, so that the identity continued and the consciousness (the very thought no more than momentarily interrupted), so that to all intent and purpose the being was the same.

There were limitations to the impulse patterns, but this had nothing to do with speed, for the impulses could cross the entire galaxy with but little lag in time. But under certain conditions the patterns tended to break down and this was why there must be many stations — many thousands of them. Clouds of dust or gas or areas of high ionization seemed to disrupt the patterns and in those sectors of the galaxy where these conditions were encountered, the distance jumps between the stations were considerably cut down to keep the pattern true. There were areas that had to be detoured because of high concentrations of the distorting gas and dust.

Enoch wondered how many dead bodies of the creature that now rested in the tank had been left behind at other stations in the course of the journey it was making — as this body in a few hours' time would lie dead within this tank when the creature's pattern was sent out again, riding on the impulse waves.

A long trail of dead, he thought, left across the stars, each to be destroyed by a wash of acid and flushed into deep-lying tanks, but with the creature itself going on and on until it reached its final destination to carry out the purpose of its journey.

From WAY STATION by Clifford Simak (1963)


The transmat is actually a blasted object duplicator. A subatomic level 3D printer. What Star Trek calls a "replicator." You see, you can send the radio signal to several transmats and the traveling object (or person) will pop out of each and every one. Even worse, you can record the radio signal so it can be re-used at a latter date. And incredibly worse, the recorded signal can be edited so that the resulting object (or person) is structurally different.

This opens up several more huge cans of worms.

First off, there is the basic fact that the invention of a matter replicator will cause the utter collapse of the global economy. The collapse can be slightly less that "utter" if somebody can invent a substance that cannot be transmatted/replicated. Otherwise it will be impossible to have physical money which cannot be instantly counterfeited.

But the ethical questions grow exponentially worse once you start replicating people

Star Trek tried to dodge this problem by saying people could not be duplicated because of reasons (except those times when they could).

If you have two or more PFC Floyds, which one is legally the "real" Floyd. Which one gets his paycheck, which one is married to Mildred?

If you keep a recording of a Floyd transmatting, and one day Floyd dies in an accident, you could use the recording to bring him back to life. Can he collect on his own life insurance?

If transmatters are the kind where scanning destroys the original, you send Floyd to Mars, but then you just make a recording instead of sending the signal to a receiving transmat, are you guilty of kidnapping? Or murder, since the original is so much hot vapor? Does it stop being murder if you replicate Floyd before the trial?

If transmatters are the kind where scanning does not harm the original, is it ethical to use it to send a duplicate Floyd on a suicide mission? This was actually a common practice in the novel Farthest Star. Officials talk you into volunteering for a painless suicide mission, painless because it won't be you who is actually dying. Step into the transmat then go home to your wife. Meanwhile your duplicate does the mission and dies in agony, spending their last breath cursing the day you were born.

Even if you do not send your duplicate on a suicide mission, a proliferation of duplicates could be problematic. If your fanaticism forces you to over-use the blasted thing, you might be driven to the draconian solution used by Robert Angier in the movie The Prestige. Nasty.

The proliferation problem is also explored in Algis Budrys' Rogue Moon.

In George O. Smith's Identity (the final Venus Equilateral story) things are really vile. Legally the duplicate of a person is property, not a human being. So if a doctor wants to perform a tricky surgery on you, they will use the replicator to run off a dozen copies of you and practice on them til they all die. Then the doctor can do the surgery perfectly. In the story nobody cares that there really is no way to tell a duplicate from an original. Well, nobody but the duplicates of course, they object strongly to being disposable.

Also in the Venus Equilateral stories, a recording can be edited. So you can make a recording of a cube of dirt, edit the recording, and use it to replicate cubes of solid gold.

Editing a recording gets more extreme in Farthest Star. They could edit a copy of you to make you a water breather or otherwise alter your biochemistry and body.


However, the proliferation problem might not arise. It seems that in quantum mechanics there is something called the No-cloning theorem. It states that it is impossible to create an identical copy of an arbitrary unknown quantum state (quantum states cannot be copied).

What does this mean? It means Captain Kirk cannot be scanned by the transporter, and have an exact quantum-level duplicate created down on the planet Vulcan while Kirk One remains on the Starship Enterprise. The duplicate can be an atomic-level assemblage of meat, but it will not have copies of the quantum-level stuff (such as the pattern of moving electrons in Kirk's brain that encodes his thoughts, personality, and memory). Basically Kirk's dead body materializes on the planet while the still alive Kirk One on the Enterprise is annoyed.

Related is the No-teleportation theorem from quantum information theory. It states that an arbitrary quantum state cannot be converted into a sequence of classical bits; nor can such bits be used to reconstruct the original state. This is implied by the no-cloning theorem: if it was possible to convert a quantum state into bits, it would be trivially easy to copy quantum states. Note the "teleportation" they are talking about is totally different from quantum teleportation (see below).

What is allowed is Quantum teleportation. This allows a quantum state to be destroyed in one location and an exact replica created at a different location.

What does this mean? The transporter can make a perfect quantum-level copy of Captain Kirk down on the planet Vulcan if the quantum-level information in Kirk One on the Enterprise is totally destroyed. Including the pattern of moving electrons in Kirk's brain that encodes his thoughts, personality, and memory. Basically Kirk One on the ship drops dead, killed by the scanning process, and a living Kirk Two materializes on Planet Vulcan while finishing the thought he had a microscecond ago.

For an in-depth philosophical analysis of this concept in comic-book form read this Existential Comic.


With this technique, one makes two points in space contiguous — somehow. Generally one of the types of Discontinuous ("teleport-like") faster-than-light drives are used as a model. The two points might be brought together by folding space in the fourth dimension. A wormhole or Einstein-Rosen Bridge might be utilized.

The point is that unlike replicator-like transmats, these do not change the traveler. Instead they change the space in between the start point and destination, reducing it to zero.

Examples from science fiction include:

Fringeworthy is a ground-breaking role playing game about ancient teleportation gates, created by Richard Tucholka in 1982. The gates looked like upright 26-foot-diameter rings with a ramp leading to the center, with a control panel on a pylon at the foot of the ramp. The gates used a crystal based technology that only worked for people born with the "Fringeworthy" gene. Some of the destination were parallel time-lines of Earth, others were alien planets.

Stargate is a film about ancient teleportation gates, created in 1994. It later became a media franchise. The gates looked like upright 22-foot-diameter rings, often with a ramp leading to the center, and often with a control panel on a pylon at the foot of the ramp. The gates used a crystal based technology that worked for anybody who could figure out how to use the control panel. The destinations were alien planets.

Perry Rhodan Transmitters

The on-going Perry Rhodan series (currently up to around issue #2931) has a variety of matter transmitters, instead of the single variety seen in Star Trek. Some are due to different tech levels, others are retcons insisted upon by the series science adviser.


(from notes supplied by Michel Van)

Perry Rhodan and the protagonists first encountered a matter transmitter early in the series: issue #14 Das Galaktische Rätsel (The Galactic Riddle). As part of a interstellar scavenger hunt mandated by a slightly deranged weakly godlike entity, our heroes must utilize the entity's "cage transmitter". The writers use the problematic "We Can Rebuild You" handwaving, where the travelers are disassembled atom by atom and reassembled at the destination. The cage is to prevent the intrusion of foreign objects (like flies).

Kurt Mahr, then science adviser for the Perry Rhodan series, deeply disliked using that explanation, probably due to all the nasty cans of worms it opens (which you can read about above). It was also practically identical to the explanation used for Star Trek's "transporter", which dilutes Rhodan's originality. In 1962 Mahr left the post of Perry Rhodan science adviser for a job in the US aerospace industry.

In 1970 Mahr returned to his PR science adviser role, only to become rudely surprised at how deeply the flawed transmitter principle had become in the series. The problematic device was used in far too many of the stories. Unfortunately Mahr did not have the authority to veto the authors using such a popular bit of handwaving. He just had to grit his teeth and put up with it.

Thing improved in 2000 when author Rainer Castor joined the Perry Rhodan writing team (a remarkable man who passed on too soon, and personal friend of Michel Van). Castor became author, science adviser, and keeper of the series database. Castor shared Mahr's dislike of the disassemble/reassemble explanation. As it turns out lots of the readers were unhappy as well. Castor did some brainstorming with fans on the Perry Rhodan Technik Forum. Castor also did some studies of the mathematics of the concept.

Castor invented a new explanation of the transmitter operation. This new concept not only avoided the nasty pitfalls of the old concept, but also was internally self-consistent with the other science-fictional science in the Perry Rhodan series. And it had absolutely nothing in common with the Star Trek transporter.

In the Perry Rhodan universe their technology for faster-than-light starships, antigravity, and power generation depends upon manipulating "hyperspace" and "hyperenergy." So it would be internally self-consistent if the matter transmitter technology also utilized this. Now, granted, if all you have is a hammer, everything looks like a nail. Even if it actually a screw. Thus it is a rule for science fiction writers to avoid using their fabulous science-fictional breakthrough as the solution for everything. But as Hector Barbossa observes, it is more what you'd call 'guidelines' than actual rules. And welcome aboard the Black Pearl.

Anyway if there exists hyperenergy, it has to come in positive and negative charges. As a general rule opposite charges attract. A negatively charged electron will move toward the positively charged pole of an electrical battery. The idea is when a person steps into the matter transmitter, it charges them up with a negative hyperenergy static charge. This will attract them to the positive hyperenergy static charge on the destination matter receiver. Since this is hyperenergy, the person will not move through normal space but instead will jump through hyperspace. They will suddenly appear at the destination receiver, without needing any problematic disassembly and reassembly. Nor any unfortunate resemblance to the Star Trek transporter, for that matter.

This also allows the teleporting mutants in Perry Rhodan's Mutant Corps to jump from spot to spot by simply creating hyperenergy static charges with the power of their mutant brains. Instead of with the power of their mutant brains disassembling an object into atoms, moving them, and reassembling them atom-by-atom. Which is a lot to ask of a mutant brain, especially if the object being disassembled is the mutant brain itself.

Unlike Mahr, Castor did have the authority to make canon this new explanation of matter transmitters.


Mono-polar Transmitter

This is the simplest and lowest tech-level of the transmitters. It does require both a transmitter and receiver.

Cage transmitters have a wall surrounding the transmitter to prevent the intrusion of foreign objects. They are immune to hyperimpedance in the surrounding hyperspace. The disadvantage is they are relatively large and bulky.

Archway transmitters are not enclosed by a wall. An arch-like structure generates a continuous transmitting field. Any object entering the field is automatically transported to the receiver. Stripped-down versions are easier to transport to wilderness (or enemy-held) locations and assembled on the spot, than are the more bulky cage transmitters. The disadvantage is archway transmitters are more vulnerable to hyperimpedance in the surrounding hyperspace, making them dangerous to use.

Sun Transmitters are powered by networks of suns, so their range is up to two million light-years (between galaxies). These were constructed by the now extinct Lemurian empire.

Time Transmitters allow time travel between transmitters and receivers located in different time periods.

Duo-polar Transmitter

These are of a higher tech-level than mono-polar transmitters. They can operate in either transmitter-less mode or in receiver-less mode. The duo-polar transmitter can [a] transmit an object from its transmitter platform to any location in range, no receiver required or [b] grab an object in range that is not on a transmitter and teleport it on to the duo-polar's receiver platform. As noted above this will be an unreasonably powerful weapon, unless there is some way to shield against transmission. With energy screen, for instance. In the Perry Rhodan series this technology remains beyond the ability of the Solarian empire.

Transform Cannon is a weapon used to transmit an explosive device deep into the heart of an enemy starship. It cannot transmit with any stability, the object explodes at the destination. This is not a problem since the object is a bomb to start with, the instability just increases the explosive force. Transform cannons cannot grab objects, they can only transmit.

Space-Time Transmitters are used to store objects. No time passes for the object, much like a Larry Niven stasis field. You pop the object into the Space-time transmitter, take it out of the same transmitter some time later, but the object is perfectly preserved. Basically it transmits the object through time to the point where it is retrieved.

Time Transmitters are similar to mono-polar time transmitters. They do not require a receiver. However, from a specific time transmitter an object or person cannot be sent back in time prior to the construction of the time transmitter, nor into the future past the destruction of the time transmitter. This is actually a common limitation of the more realistic theories on time travel.

Situational Transmitters are like stationary versions of a starship's Linear FTL engine. It projects an energy field around an object and catapults it into Linear FTL space toward a destination. The object does not need to have an engine.

Three-polar Transmitter

These do not require the object to either start at a transmitter nor end at a receiver. The Three-pole transmitter can grab an object which is not on a transmitter, and teleport it to a location which is not at a receiver. Their range is unlimited, anywhere in the entire universe. They can be used for time travel, not even limited to the period between the transmitter's creation and destruction. You can even change you mind and alter the destination of the hapless person or object while it is still in transit. It mostly operates in higher dimensions, like between the 5th and 6th dimension or even between the 6th and 7th dimension. It doesn't really have any limits.

They are ultra high-tech, used by weakly godlike entities.


By the year 2000 the Perry Rhodan writers had abused the matter transmitters so shamelessly that they became ridiculously unbelievable. There were few limits, and the transmitter ranges were outrageously long. Even the readers were complaining. So in 2003 a decision was made to "re-set" the tech level to give the matter transmitters more reasonable limitations.

Since the transmitters utilize hyperspace, the writers postulated a change in hyperspace. A strange hyperimpedance came over the hyperspace surrounding not just the galaxy, but the entire universe. For handwaving reasons the hyperimpedance rendered archway transmitters virtual death-traps. The limited hyperspace static charging allowed by an arch was not enough to overcome hyperimpediance.

Cage transmitters were relatively unaffected by hyperimpedance. Obviously they have more complete coverage around the transmitted object, allowing better hyperspace static charging. A pity the hyperimpediance reduced the maximum transmission range to only five light years, but behind the scenes the writers considered this to be a more reasonable limitation. The maximum explosive force from a transform cannon was reduced from 10,000 gigatons (more than Shoemaker-Levy fragment G, about 600 time the current world's nuclear arsenal) to only 2.5 gigatons (about fifty times as large as the Tsar Bomba hydrogen bomb).

To get more range you need to use Sun transmitters powered by networks of suns, which again is a more reasonable limitation.

The hyperimpedance was caused by the godlike entities know as the Cosmocrats, who thought the Solarian empire and other relatively ant-like galactic civilizations were making a nuisance of themselves.

Weaponized Transmats

Half of the reason that receiver-less and transmitter-less transmats are so unreasonable is that they can be used to make some rather ugly and unstoppable weapons.

  • A receiver-less transmat can make a nuclear warhead unexpectedly materialize close to an enemy warship. Or inside the warships defensive force fields. Or inside the warship itself. Heck, materializing a puny hand grenade inside the warship's CIC will probably kill everybody in it and at least temporarily disable the entire ship. The same goes for assassinating the leader of a hostile nation by materializing a nuclear warhead inside their underwear or up a convenient body orifice.
  • A transmitter-less transmat can assassinating the leader of a hostile nation by making their still-beating heart appear in the transmat, while the rest of their body in the original location futilely tries to live without it.

A transmat that requires both transmitter and receiver can still be pretty nasty, if the transmitter can transmit something that is not actually in contact, and the transmitter is small enough to fit in, say, a rifle-sized long arm.

  • In Mindbridge by Joe Haldeman, a transmat transmitter is a special crystal. Some aliens manage to make a gun-like device with a tiny crystal, which will transmit everything inside a cylindrical volume about one centimeter in diameter and about ten meters long. Basically it acts like a disintegrator ray. It cuts a long thin tunnel in the target. In the novel the transmat needs no receiver, but the weapon will still work if one is required. The receiver (where ever it is) will just have to be periodically hosed off to remove the cylinders of armor, bone, blood, and body tissue.

  • In The Armageddon Inheritance by David Weber, "warp rifles" have much the same effect as the Mindbridge weapons. Its just they send the cylinders into hyperspace. Warp grenades send into hyperspace anything within the "blast radius". If you are lucky, half of you will be inside and half out, killing you instantly. If you are not, you will find yourself floating in trackless infinity of hyperspace with your lifespan limited to your oxygen supply. And nobody will ever find your body.

  • In The Universe Between by Alan E. Nourse, researchers manage to anger being who live in another dimension by accidentally mutilating the other dimension. The beings retaliate by trying to remove the machine doing the mutilating. The researchers start running around like their hair is on fire when volumes the size of city blocks start randomly vanishing all over New York City.

In some science fiction stories, the operating principle of starships faster-than-light drives are based on transmat technology. Occasionally this can be turned against the starship as a weapon.

  • In the wargame Starforce Alpha Centauri the FTL engines of the starships are actually psionic women, who teleport the ships from star to star by using the power of their minds. As a weapon the psionic team can send a telepathic command (a "combat cast") to an enemy ship's psionic team, forcing them to make an uncontrolled teleport to an awkward location. Such jumps are typically five times the distance of a "safe" jump, so it will take the enemy ship a long time to crawl back to the battle. A ship's psionic team can divert part of their power into an "anti-cast" to try and mute an enemy's combat cast.

  • In War in Heaven by David Zindell starships move by opening up wormhole entrances before them and moving through. The entrance location and destination are created through a metaphysical process that the pilot controls by using mathematical theorems. Whatever. The point is that in combat, the idea is to open a wormhole in front of your opponent that will teleport them to the surface of a sun or other deadly location.

Transfragging is the use of a weaponized translocation device to destroy a target, most commonly by interpenetration (i.e., translocating an object to within another, preexisting, object), but the term is also used to refer to simply using the translocator to transmit bombs or other weapons to within a given target.

Since all known or even theoretically possible translocation devices either make use of wormholes or similar metric warps, or alternatively obey the principle of equivalent spatial exchange, and in both cases require a cooperative receiver, transfragging is for all intents and purposes not possible.

Don’t spread it about, though. Belief in the possibility keeps lots of weapons designers in unhealthy places from working on anything that might actually be dangerous.

– Once Again I Have Been Thwarted: Hopeless Ambitions for Budding Evil Geniuses, Bad Stuff Press (8135)


      Lord Nikolos suddenly stood away from his table. The other lords followed his lead, and some began talking in groups of two or ten, while others filed out of the hall. Bardo and the master pilots sitting at Danlo’s table immediately began to discuss the forcing of an enemy’s lightship into the fiery centre of a star and other battle stratagems.

     He then enjoined them above all else to avoid war if they could. Danlo, along with the Lord Bede, was to be given a chance to reason with Hanuman li Tosh. If a display of virtuosity and threat might bring peace, they were to use their lightships towards this end only. And if battle came to them howling on an ill–wind of fate, pilots were to fall in violence only against other pilots and ships of war. They were not to attack merchant ships, nor any world or peoples supporting Hanuman and the Way of Ringess. Specifically, Lord Nikolos charged them with upholding the Laws of the Civilized Worlds. They were not to arm their lightships with hydrogen bombs or other weapons of genocide. They were not to infect planetary communications’ systems with information viruses or disable them with logic bombs. The purpose of the war must be as clear to them as a diamond crystal: first, they were to stop Hanuman from using the Old Order to spread Ringism to the Civilized Worlds.

     And so the pilots of the New Order returned across the stars as they had come only a few years before. Although this part of their journey from Thiells to Farfara was much the shortest, in distance, as measured in time it took many days to fall even a few hundred light years between such stars as Natal and Acayib the Brilliant, for the manifold underlying the Vild was as changeable as quicksand and mappings made one moment might prove worthless the next. The Sonderval, though, led the lightships with panache and good order past Kefira and Cho Chumu, and Rhea Luz, all hot and swollen with its angry red light. Perhaps it was good chance—or only fate—that no pilots were lost during this first fenestration of window (stargate or wormhole mouth) to window giving out on the treacherous stars. Once, when they fell through a Danladi fold caused by the explosion of some recent supernova, Ona Tetsu’s Ibi Ibis almost vanished into an infinite series of infoldings. But with great presence of mind characteristic of all her famous line, that wily pilot found a mapping which took her through a window to the Birdella Double, which was the next star pair in the sequence of stars that the Sonderval had set. There she waited for the two hundred lightships to rejoin her—waited with great coolness as if she hadn’t almost lost her life like a child smothered in sheets of wildly flapping plastic.

     Most of the pilots, of course, would have liked to prove their virtue by finding mappings independent of the others, but accidents such as Ona’s befell few of them, and the Sonderval had ordered them to stay together. And so they moved through the Vild as one body of ships, remaining always within the same neighbourhood of stars. They passed Ishvara, Stirrit and Seio Luz, a cool yellow sun almost identical in shape and colour to the Star of Neverness. And Kalkin and Vaishnara, and others, and finally they came to Sattva Luz, a brilliant white ball of light just within the inner envelope of the Vild. From here, their mappings would carry them only a few more stars to Renenet and Akar, and thus to Shoka and Savona, where they would break free from the Vild’s outer envelope and look out on Farfara and the stars of the Civilized Worlds. It was here, just beyond Sattva Luz’s intense gravity field, that they came upon a quite deadly phase space. Or rather this menace of the manifold came upon them. Some of the surviving pilots were to describe it as like an earthquake; others spoke of boiling oil or point–set correspondences that shattered like a dropped cup. For Danlo wi Soli Ringess, caught in the worst part of the phase space, it was as if one moment he were floating on a calm blue sea and the next, a tidal wave of every colour from ruby to violet was breaking over him. He had almost no time to find a mapping to a small white dwarf near Renenet. Others, however, were not so lucky. (Or skilful.) Three pilots died that day: Ricardo Dor, Lais Blackstone and Midori Astoret in her famous Rose of Neverness. None will ever know how the manifold appeared to them in the last moment before they were crushed into oblivion. But all the survivors agreed that they had lived through one of the worst mathematical spaces ever encountered and were very glad when the Sonderval called a halt near Shoka to speak the dead pilots’ names in remembrance.

     It was just after they had fallen out into realspace around a red–orange giant named Ulladulla. The lightships had kept in good order, gathering as a group near point–exits only a few million miles from Ulladulla’s flaming corona. But the black ships and deep–ships, as they fell out from the manifold’s point–exits, scattered themselves through space like hundreds of dice cast onto black felt. As always, the Sonderval, in his brilliant Cardinal Virtue, would have to wait for them to make their corrective mappings and rejoin the lightships. This always took time, and the Sonderval always counted the moments like a merchant begrudgingly fingering over golden coins to a tax collector. And this time, the regrouping was to take more than a few moments because further in towards the sun, half–concealed by Ulladulla’s fierce radiance, five lightships from the Order on Neverness waited to ambush them.

     So blindingly quick was then attack that neither the Sonderval nor any other pilot save one identified the names of their ships. But it was certain that they were Neverness lightships which had journeyed to this star to terrorize the black ships and their pilots. Any ship, of course, as it opens windows in and out of realspace will perturb the manifold like a stone cast into a quiet pool of water. A skilful pilot, if she has manoeuvred close enough to another, can read these faint ripples and actually predict another ship’s mappings through the manifold. But if many ships are moving as one towards point–exits around a fixed star, it requires much less skill to make a probability mapping, for the perturbations merge like a streaming river and are easy to perceive. If the pilots of Neverness had known of the gathering on Sheydveg—as they must have known—then it would be a simple thing for them to divide their forces and lie in wait along the many probable pathways leading to Sheydveg. In time, one of their attack groups would be almost certain to detect the raging river of the Sonderval’s fleet. It would be a simple stratagem, yes, but a foolish one, or so the Sonderval had calculated when he had weighed the risks of various approaches to Sheydveg. For there were many pathways through the manifold, as many as sleekit tunnels through a forest, and whoever led the Neverness pilots would have to divide his ships too thinly.

     If the purpose of this attack had been to vanquish the New Order’s fleet, then the Sonderval’s reasoning would have proved sound. But the five lightships’ purpose was only terror. In truth, the lightships of the Sonderval’s fleet were never in danger, nor were the main body of black ships and deep–ships. But a few of the most scattered of these were in deadly danger. The Old Order’s lightships fell out of the sun upon them like hawks among a flock of kitikeesha birds. Using a tactic devised in the Pilots’ War, they manoeuvred close to then target ships and fixed a point–source into the manifold. In essence, they made mappings for their victims. Death–mappings: their spacetime engines opened windows into the manifold and forced a deep–ship or black ship to fall along a pathway leading straight into the heart of the nearest star. These mappings took only moments. And so in less than nine and half seconds, the pilots from Neverness darted in and out of realspace like needles of light. They sent two deep–ships and thirteen black ships spinning to their fiery deaths inside Ulladulla. And then as quickly as they had appeared, they were gone, five wraithlike ships vanishing into the manifold towards other stars far away.

     When he returned to the spaces of Ulladulla three hundred seconds later, he found that the Sonderval had drawn his shaken fleet together. He gave a quick account of his pursuit of the Neverness ships. By light–radio he told the Sonderval and all the pilots of the lightships (and only these) what had happened during the brief time he had been gone. In the pit of the Snowy Owl, a glowing hologram of Bardo fairly popped out of the air, and this is what Danlo heard the huge man say: ‘Five ships, and they scattered in five different directions. So I had to choose one pathway, one ship. I was lucky, by God! I was still within a well–defined region of one of them, and was able to close the radius of convergence quickly. I came upon him by a blue hotstar five light years from Ulladulla. When I fell out into realspace, I saw that it was Marrim Masala in the Golden Rhomb. He has the ugliest little ship with its ugly straight wings and ugly tail. Had, that is—I sent him and his goddamned ship to hell inside the star, too bad. But I’ve no regrets, for he slaughtered innocents. And in the Pilots’ War he killed Lahela Shatareh, and who could forgive him for that?’

     The battle that Bardo had fought with Marrim Masala had been much like any contest between two lightships: nerve–shattering, fierce and quick. Like two swords flashing in the night, Bardo’s and Marrim’s ships slipped in and out of the manifold seeking an advantageous probability mapping. Bardo, the more mathematical and cunning of the two pilots, in some hundred and ten seconds of these lightning manoeuvres, had finally prevailed. He predicted which point–exit the Golden Rhomb would take into realspace, and he made a forced mapping. And then the Sword of Shiva swept forwards and sliced open a window into the manifold. And the Golden Rhomb instantly fell through this window into the hotstar’s terrible fires.

     It took Danlo only a moment to decide to flee. He closed his eyes, envisioning the colours and contours of the manifold in this neighbourhood of space; he listened to the whispers of his heart, and then he reached out with his mind to his ship’s–computer to make interface. And then he was gone. The Snowy Owl plunged into the manifold like a diamond needle falling into the ocean. He knew that the other ships would follow him. Very well, he thought, then let them follow him into the darkest part of the manifold, where the spaces fell deep and wild and strange. In the gentle topology of the Fallaways few such spaces existed, but there were always Flowtow bubbles and torison tubes and decision trees. And, of course, the rare but bewildering paradox tunnels. No pilot would willingly seek out such a deranged space—unless he were being pursued by seven others determined to destroy him. By chance (or fate), such a tunnel could be found beneath the blazing fires of Shoshange. From a journey that the Sonderval had once described making as a young pilot, Danlo remembered the fixed–points of this tunnel. And so he made a difficult mapping. He found the paradox tunnel all infolded among itself like a nest of snakes. His ship disappeared into the opening of the tunnel—and to any ship pursuing him it would seem as if the Snowy Owl had been swallowed by twenty dark, yawning, serpentine mouths, all at once.

From WAR IN HEAVEN by David Zindell (1998)

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