The world of tachyons and science fiction

In previous posts in this blog I have mentioned various procedures often used by the authors of science fiction novels to make interstellar travel almost as simple and brief as today's airplane trips to different points on Earth. One of these procedures consists of disintegrating the ship and reintegrating it into the universe of tachyons: hypothetical particles, compatible with the theory of relativity, that would always travel at speeds greater than the speed of light. Thus it would be possible (in principle) to travel very fast to the point we are interested to go to, reintegrate the ship into the world of tardions (in other words, into our world), and presto! We have traveled faster than the speed of light.

In fact, the authors of these novels (of which I am one) don’t usually go into detail about what the world of tachyons would be like. We simply assume three necessary conditions for interstellar travel to be possible:

Superluminal interstellar travel

James H. Schmitz

The human imagination knows no limits. Einstein can tell us that the speed of light sets an insurmountable limit for objects with mass, but deep down we don't believe it. There has to be a way to break that limit! Otherwise, how could we reach the stars during the short span of our lives, return to Earth and tell here what we have seen?

People in our time, especially our civilization, are determined that we must get everything we want. I want to be immortal, so I must be; if I can't, at least my children or my grandchildren. (We don’t usually go beyond our grandchildren…) I want to travel to the center of the galaxy; if I can't, someone will. I want to do whatever I want with my life, so I will… no matter what!

Traveling at the speed of light

Image of
"2001, a Space Odyssey"

Actually, the title of this post is wrong. Traveling at the speed of light is impossible, because it would take infinite energy to accelerate to that speed a body with rest mass greater than zero. What I am going to talk about here is travel at relativistic speeds (close to the speed of light), which means more than 10% of the speed of light (i.e. 30,000 kilometer per second).

Interstellar travel in suspended animation

Most of the problems mentioned at the end of the previous post would disappear if the generational journey were combined with another scientific advance that does not seem, at first glance, impossible: the conservation of human beings in a state of latent life for very long periods of time. This state, which resembles what many living beings do when environmental conditions are unfavorable, is called hibernation when it is a response to cold, and aestivation when it is used as a defense against heat and dry seasons.

Under the current conditions of science, human hibernation is not feasible. It is true that it is possible to reduce the vital rhythm through the application of low temperatures, a technique that is being used in surgery to carry out complex or delicate operations, but the total suspension of vital activities is always transitory and limited to a short period of time, usually measured in hours.

Generational interstellar travel

In a subset of science fiction novels and stories, the journey to the stars is longer than a human lifetime. The space vehicles are huge, as they must be to house many cosmonauts during thousands of years. The speeds of these spacecraft are not very high, on the order of a few million kilometers per day. At that rate it takes thousands of years to cross the interstellar chasms.

The cosmonauts who reach the end of the journey are not the same ones who started: hundreds or even thousands of generations have passed their entire lives aboard a spaceship and don’t know the Sun, or life in the open air. The vehicle where they travel is a small planet: a closed entity, in perfect ecological balance. Nothing is wasted. Wastes from normal activity are recycled and reused. The cycles of water, oxygen, carbon, nitrogen and other essential elements of life must be perfectly controlled. They only eat hydroponic vegetables.

Will traveling to the stars be possible?

Will interstellar travel be possible? At the current level of our technology, the answer is clearly no. Will it be possible in the future? It is always dangerous to make predictions: reality often strays from what was supposed to happen. But it doesn't look like interstellar travel is going to become feasible anytime soon. Of course, in the scientific literature, both serious and imaginative, various methods have been proposed, some of which we’ll review in this and future posts, by analyzing the relative probabilities of each one.

Many writers consider interstellar travel the next frontier of human spread, and the only guarantee to avoid our extinction, either accidental, if a cosmic catastrophe occurs, or caused by ourselves with a nuclear war. The problem is, a trip to the stars would be much more difficult than planet exploration in the solar system. Apart from the sun, the closest star to us is 4.27 light-years away, just over 40 trillion kilometers. With our current technique, speeds of the order of one million kilometers per day can be reached, so a trip to that star would last more than one hundred thousand years. Taking advantage of the gravitational pull of giant planets, like Jupiter, it would be possible to triple the speed, but even so we are talking about tens of thousand years.

The golden rules of science fiction and my own work

Isaac Asimov

These are, according to Isaac Asimov, the two golden rules of good science fiction:

1.      Any scientific claim (even a prediction) must always be compatible with current science. It would not, therefore, be good science fiction a novel where the squaring of the circle with a ruler and compass was achieved, because it has been shown mathematically that this is impossible. Or traveling through space at a speed greater than that of light, without using some scientific trick that makes it possible to achieve it, such as going through the world of tachyons.

2.      Predicting social consequences is better than predicting technical advances. Thus, in a hypothetical novel written in the nineteenth century, predicting the parking problem would be much better than just predicting the car. An example of this kind of good science fiction, mentioned by Asimov in this regard, is Robert Heinlein's short story Solution Unsatisfactory, written in 1941, which not only predicted the atomic bomb as a means of ending World War II (in which the United States were not yet taking part), but also predicted the subsequent equilibrium between the great powers and the permanent threat of a war of extermination.

To be exact, these two laws are my elaborations of what Asimov wrote in two popular articles published in The Magazine of Fantasy and Science Fiction: Future? Tense! (1965) and O Keen Eyed Peerer into the Future (1974). To be even more exact, Asimov's laws were three and, similarly to his three laws of Robotics, he called them the three laws of Futurics.

Science and Science Fiction: mutual influences in the 20th century

H.G. Wells

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Halfway between the 19th and 20th centuries, the British H.G. Wells also practiced the literature of scientific prediction, although his predictions are usually longer-term than Verne's, more remote from the technique of his time, so very few have come to be carried out. We still don't have The Time Machine and can't see it anywhere near. We cannot make artificial men by vivisecting animals (The Island of Doctor Moreau). Nor can we make ourselves invisible (The invisible man). And fortunately the Martians have not invaded us (The War of the Worlds). In 1938, a radio dramatization of this novel by Orson Welles caused a mass panic in the United States. Despite the boom in science fiction at the time, the public was still as credulous as when it had been fooled a century earlier by the articles in the Sun.

Wells also wrote (of course) about a trip to the moon and populated our satellite with intelligent giant ants, although the procedure to make the trip is more imaginative than, and as impractical as Verne's. But his great scientific foresight success is the novel The World set free (1913), which not only anticipated the atomic bomb, but also influenced its practical realization, stimulating Leo Szilard's research on the neutron chain reaction. Although Wells also made a tremendous mistake in this novel, by predicting in 1913 that the First World War would start in 1956. But as he said a few years later: [I have] always been... a rather slow prophet. You can also see my review of this book in Goodreads.

Wormholes

Science fiction novels make it clear that, even if we were able to reach relativistic speeds (close to the speed of light), our need to personally explore the universe wouldn’t be satisfied. We’d like to travel to other stars with the same ease with which we cross the Atlantic today. We’d like to measure in days, if not hours, the time of a trip to the center of the galaxy (which probably contains a large black hole). Is there any chance of this happening?

To do this, we should discover in the future some property of the universe, now unknown, that would help us break the speed limit of light, which seems firmly established, and which would make us spend thousands of years on trips to most stars, except the nearest.

To solve the problem, science fiction authors have used essentially two different procedures:

Space as a point of concord for humanity

Start of a V-2 rocket in 1943

The exploration of space began some seventy years ago, as a continuation of the Third Reich’s war effort to develop ballistic missiles (the V-2 rocket) to bombard Britain and other places without the need of airplanes.

At the end of World War II, the two new great powers (the United States and the Soviet Union) recruited the scientists and technicians who had carried out the German advances in that field, took them to their respective countries and started programs of space exploration, whose first objective was, of course, to obtain military advantages in the cold war that had just begun. As a result of Operation Paperclip (the US recruitment program), German scientists as important as Werner von Braun went to work in the United States. An equivalent Soviet program (the Operation Osoaviakhim) did the same with other German scientists, perhaps less known, but equally efficient. With their help, both superpowers began a space race that would last several decades.

Are we alone in the galaxy?

Enrico Fermi

In their famous book of hard scientific popularization, The Anthropic Cosmological Principle, published in 1986, the cosmologists John Barrow and Frank Tipler offer a proof that we are alone in the galaxy by means of a variant of the Fermi paradox (if there are any extraterrestrial intelligences in the Galaxy, why aren’t they here?) which can be summarized as follows:

1.      In 100 years we will have succeeded in creating life in the laboratory. Not just life, we will also be able to build a complete human being from its chemical components and information about the human genome, which can be stored in a digital memory.

2.      In 100 years we will have managed to build artificial intelligences as intelligent as human beings, able to replace us in any place and circumstance.

3.      Our current space technology allows us to reach a speed of 0.0003 c (where c is the speed of light). At that speed, a spaceship would take about 50,000 years to reach the nearest stars.

The v>c world

Albert Einstein

In 1967, Gerald Feinberg game the name tachyon (from the Greek tacus, fast) to hypothetical particles whose possible existence had been proposed five years before by other researchers. Tachyons would have a unique property: they always move at speeds greater than the speed of light. Their mathematical behavior would not infringe the limitations of the special theory of relativity, which prohibits bodies with mass reaching the speed of light. Unfortunately this would cause other problems.

The idea of ​​the possible existence of tachyons was embraced with joy by science fiction writers, for they seemed to make interstellar travel possible in a reasonable time. For this, the following procedure would be effective: