Reach Out & Teleport Someone

As the century that saw the birth of electronics and optoelectronics draws to a close, virtually everything we have wished to do in the field of telecommunications is now technically possible. The only limitations are financial, legal or political.

But, have we indeed reached the limits of communications technology? Men have always proclaimed that there is nothing more to invent, and they have always been proved wrong.

Electricity has been our most valuable and versatile tool for only a small fraction of human history—yet, see what it has done in its brief time. We are now uniting electron and photon to develop the science of optoelectronics, which will create devices whose names will be as familiar to our children as TV, video tape, CD, Comsat, laser and floppy disk are today— and as meaningless to us as those would have been to our grandparents.

Since the existence of radio waves would have been inconceivable just a few lifetimes ago, one cannot help wondering what other useful surprises nature has up her sleeve. The electromagnetic spectrum has been thoroughly explored—contrary to Edgar Rice Burroughs' hero John Carter, who discovered two new colors on Mars. But are there any other radiations and fields to be found, perhaps with properties that might make them even more valuable than radio waves?

It must have been 60 years since I encountered a story in The Boy's Own Paper—almost the only source of science fiction in my youth—about a telescope that allowed one to see through the solid earth and observe events on the other side. I doubt if the author went into technical details about his planet-piercing radiation; he probably talked glibly about X rays—after all, they go through solid matter, don't they?—and left it at that.

Amazingly, there are indeed rays— or rather particles, which in modern physics amount to the same thing—that can travel right through the earth as if it weren't there. The ghostly neutrino interacts so rarely with what we like to call solid matter that it could easily pass through a sheet of lead millions of miles thick.

Our nuclear reactors generate neutrinos in enormous quantities. If a neutrino source could be modulated to carry a signal, such a signal could be beamed straight through the earth, traveling from pole to pole in a fraction of a second. There would be none of the annoying time delays unavoidable with satellites in stationary orbit.

There are some practical difficulties. One way to modulate a neutrino source is to switch a nuclear reactor on and off. Nuclear reactors do not appreciate such treatment vide Chernobyl), and even if one were specially designed for this purpose, the rate of data transmission would be about the same as the first transatlantic cable—a few words an hour.

And that is the least of the problems. To receive a message, you have to collect something, and because matter is so transparent to neutrinos, they are almost impossible to detect. To catch a neutrino, you would fill a tank with several hundred tons of liquid, in the hope that one or two particles a day of the quadrillions passing through might be unlucky enough to make a direct hit on a nucleus and produce a signal indicating their demise.

At the risk of having Clarke's first law—"When a distinguished but elderly scientist says that something is impossible, he is very probably wrong"—thrown at me once again, I will venture a daring prediction: No one will ever put a wrist-watch neutrinophone on the market.

If you think that neutrino communications is a hopeless prospect, here is an even more unlikely one.

According to Einstein's general theory, the universe is permeated by gravitational waves that travel at the speed of light. During the last quarter century, heroic attempts have been made to detect them, so far without success, but few scientists doubt their existence. Ever more sensitive instruments are now searching for them, however, and it seems unlikely that they will elude us much longer.

The difficulty of detecting gravitational waves is nothing compared to the problem of generating them. To get a power equivalent to that of a medium-sized radio station, you need to take a couple neutron stars (only a few kilometers across, but weighing several billion tons per spoonful) and shake well. Alternatively, trigger a supernova explosion, which will collapse a star to a neutron core that vibrates briskly for a few seconds. This will send the universe a message that says, if not "I'm here," then, at least, "I was here."

Even if neutrino beams and gravitational waves could be used for telecommunications, they would be limited by the speed of light. As we move out into the solar system, it would be really useful to have something move a lot faster than a miserable 186,000 miles a second. Because of this speed-of-light limit, a real-time conversation with anyone beyond the moon is highly impractical. You can fax your Mars office—but you wouldn't want to telephone it.

Contrary to popular opinion, many things move faster than light; it depends on what you mean by "things." Let me give an example familiar to most air travelers.

Airports have a line of strobe lights down the center of the runway that can be triggered in sequence to give a visual aid to a pilot making a night landing. From the air, it looks as if a bolt of lightning is hurtling along at enormous speed.

Obviously, the interval between flashes can be adjusted to any gap desired; the shorter it is, the quicker this visual phantom will appear to move down the runway. It would be easy to make it move faster than light; in fact, if the flashes were simultaneous, its speed would be infinite.

A little thought will show that nothing is really moving. No message—no information—is being transmitted. There are similar examples in physics and in everyday life. One of the most dramatic may be seen along a breakwater during a storm. As a line of waves moves toward a sea wall, the explosion of spray can race along the wall at an enormous speed; the smaller the angle of approach, the greater its velocity. When the approaching wave front is exactly parallel to the breakwater, spray erupts along its entire length simultaneously—i.e., the apparent speed is infinite. But nothing material is moving at more than a few score miles an hour.

Is there any way that we can ever break the light barrier? There are a few far-out possibilities.

Although Einstein's equations state that no object can travel at precisely the speed of light (because its mass would then be infinite), that does not rule out the existence of particles that can never travel slower than light. It is true that such particles (christened tachyons, meaning "swift ones") would have some odd properties; but who would have believed in the existence of neutrinos a few decades ago?

In any event, no one has been able to prove that tachyons are impossible, and we thus can conjure them into existence by applying the totalitarian principle, useful in many branches of physics and astronomy: "Anything that is not forbidden is compulsory." Whether we will be able to detect tachyons—still less use them—is another matter. Meanwhile, they have been a godsend to writers of science fiction.

Another godsend—to those who understand it, which does not include this writer—has been the notorious Einstein-Podolsky-Rosen paradox. According to this, under certain conditions, one particle can have an instantaneous influence on another, even if the two are light-years apart. Although the EPR paradox appears to have been confirmed in exquisitely sophisticated laboratory tests, debate continues as to what it really means. The majority opinion is that, even in theory, it will not permit supra-light-velocity transmission of signals. Too bad.

Some unorthodox scientists have invoked EPR and similarly weird quantum effects to explain a type of communication that probably does not exist—telepathy, or the direct contact between two human minds without any physical connection. There are so many apparently well-authenticated examples that I hesitate to dismiss it completely. However, even if natural telepathy does not occur, I have no doubt that future science will be able to provide an artificial variety. As we better understand brain function and the central nervous system, we may literally learn to read thoughts. To a limited extent, this exists already, with the bionic limbs now available to amputees. A person wearing such a prosthesis simply wills a movement—and electronics does the rest. I am not sure that I would altogether welcome a surgically embedded microchip to replace the telephone, but it's an interesting possibility—especially to the various military labs that are working on it at this very moment.

But enough of these humdrum, down-to-earth concepts. Let's consider the most speculative of all: teleportation—the long-distance transmission of material objects, including persons. Seemingly fantastic, and certainly unlikely, teleportation does not appear to be completely forbidden by the laws of physics. The required technology, (concluded on page 193) Reach Out (continued from page 152) however, is as far beyond us today as TV would have been to Leonardo da Vinci.

Scanning and reconstructing a human being—or even an inanimate solid object—would be orders of magnitude more difficult than creating a system that carried only images. The amount of information involved would be so enormous that its transmission might take astronomical periods of time. A circuit with the same capacity (or bandwidth) as one of today's TV channels would take about 20 million million years to transmit a human being's physical pattern. It would be quicker to walk. Even fiber optics would knock off only one of those millions, so I fear it will be a long time before anyone says the equivalent of "Beam me up, Scotty."

Perhaps the feat could be accomplished, under certain circumstances, not by a scanning technique, but by taking a short-cut through the wormholes in space postulated by some physicists. Unfortunately, only very small worms could make it through these holes, which appear to be subnucleonic in size. Stephen Hawking summed it up in a TV discussion with Carl Sagan and myself when he said that a wormhole traveler would end up looking like spaghetti or "a passenger in some airlines my lawyer won't let me mention."

•

As we enter the final decade of the most brilliant yet barbarous century mankind has ever known, we should feel a kinship with the Roman god Janus, who simultaneously looked forward and backward. But Janus was also the god of beginnings (hence January). If we can learn from the past, there is hope for the future.

That future, as H. G. Wells warned us long ago, will be a race between education and catastrophe. Television is the most potent educational medium ever devised, and programs deliberately devised to instruct are only the tip of an enormous iceberg. Every time the camera presents a political demonstration, a parliamentary debate, a UN relief operation, even a sporting event, it serves the cause of education, in the widest sense of that word.

This was proved most convincingly during the August revolution in the Soviet Union, which appears to be rapidly reversing the October 1917 one. In his August 24, 1991, "Letter from America," Alistair Cooke contrasted 1917's ten days that shook the world with this year's 60 hours. The coup failed, he stated, "mainly because of something new—satellite broadcasting." He paid tribute to CNN, which, as in the Gulf war, served as a two-way, interactive medium, creating history as it reported it.

The battle over Kuwait was, in fact, the first time in history that the U.S. saw what war—and, even more importantly, its aftermath—was really like. In Vietnam, and even in the Falklands conflict, the images were already history when they reached the viewer. There is an immense psychological gulf between real time and replay.

During the Gulf war, communications satellites became the conscience of the world—a function already rehearsed in such global telecasts as the concerts in aid of Bangladesh and Ethiopia. There is a danger, of course, that overexposure to disaster and tragedy will induce compassion fatigue, but the alternative—the indifference of ignorance—is surely worse.

Another danger, and perhaps a more serious one, is that these wonderful new services may overload our capacity to absorb them. There is still much more to come. Already there have been spectacular demonstrations of high-definition television (HDTV), and now there is the equally exciting promise of applying digital sound to inexpensive radio receivers—both using direct-broadcast satellites. DB radiosats may make the old short-wave services instantly obsolete, and give rise to new global networks of major importance.

Yet, bombarded with megabytes, we may simply switch off, or not bother to use, these wonderful new toys once the initial novelty has been exhausted. Satellite empires have already risen and fallen, and the money lost in the early Atlantic cables has been eclipsed by the fortunes that evaporated in mergers and launch-pad explosions.

But these, I am sure, are temporary setbacks. The sky will continue to fill with new stars, whose names would puzzle the old-time astronomer—Anik, Palapa, Statsionar, Arabsat, Asiasat. Let us use them well, always remembering that information is not knowledge and knowledge is not wisdom.

Let me close by recalling one of the most powerful tales from the Old Testament—the Tower of Babel. A recent article in Scientific American traces nearly half of today's languages to a homeland only 300 miles north of Babylon. Be that as it may, there is an eerie symbolism to the fact that today's makers of communications satellites are now busily unbuilding the Tower of Babel 23,000 miles above the equator.

To quote from Genesis 11: "And the Lord said, 'Behold, they are one people, and they have all one language; and this is only the beginning of what they will do; and nothing that they propose to do will now be impossible for them.'"

On that first occasion, those words were a warning of disaster. Today, they should be a message of hope, a description of the future that lies within our grasp.