Unpublished manuscript, written August-September, 1959
By William D. Conner
Time travel has long been a popular theme of science fiction. No other means of connecting the present with the future or past is more convincing to the reader. Time travel solves the difficult problem of bridging the gap between the present and some wildly different future or past. Time travel allows our imaginations to roam freely from century to century, while interpreting the future and past for us in the terms of the present. Consequently, time travel and the time machine have been almost as important to science fiction as space travel and the spaceship.
But unlike the spaceship, time machines are utterly impossible. There is no place for a workable time machine in our universe. It is impossible to build a machine for travel in a medium which does not exist. Time travel should not be the subject of science fiction. Instead, it belongs to the realm of fantasy, where all things are possible. Science fiction should be based on real science. It should not contradict factual science without a very convincing argument by the author that such a contradiction may be possible. For example, contemporary science knows of nothing that can travel faster than the speed of light. Traveling faster than the speed of light is theoretically impossible.
Few science fiction authors bother any more to go into detailed explanations of how it might be possible for spaceships to travel faster than the speed of light. "Hyperspace drives" and other light-speed space drives have long been familiar to science fiction readers. Authors who wrote stories for the pulp magazines of the 1930s developed the fictional science justifying light-speed space drives. Like the literary theorizing about space travel, most of the science fiction explanations of how time travel could work has been bunk. It consists of nothing but nonsensical incantations of scientific terms. This may be permissible in fantasy, but science fiction should be restricted to what is possible, or what seems possible, in light of contemporary science.
Einstein's concept of space-time offers a formidable argument for the dismissal of time travel as an utter absurdity. Yet science fiction books and magazines are filled with stories of people jumping from one point to another in a "time stream," creating disturbing paradoxes in "the present world" they have left behind. These stories are the worst offenders of these crimes of ignorance. Einstein's space-time concept should leave little doubt in the minds of those who understand it that there is no such thing as a "time stream."
Unfortunately, this concept is not easily understood by people who lack a good knowledge of mathematics and geometry. Equally unfortunate is the fact that in Einstein’s concept, space and time get mixed together so thoroughly that it is sometimes impossible to make a distinction between them.
Apparently, it was for this reason that the term "space-time" was coined. Despite this confusion, Einstein's concept works out beautifully in the language of mathematics. I think the source of the literal confusion among the terms "space", "time", and "space-time" lies in the fact that Einstein's concept does not fit old definitions of space and time.
Common dictionary definitions of time tell us that time is the interval between events in which something acts, exists, or occurs. This is about as helpful to a time machine enthusiast as telling a sailor that water is wet. We need to know just what constitutes the phenomenon of time. The dictionary definition says that time is an interval between events in which something acts (an event), exists (a lack of event), or occurs (an event).
When the dictionary definition is changed by inserting "event" or "lack of event" in the appropriate places, the definition begins to take on a bit more meaning than "water is wet." Time now becomes an interval between events in which other events occur or fail to occur. Thus action and occurrence are associated with events, and existence implies a lack of event.
Time thus emerges as an intellectual analysis of the physical realities which give us our sense of time "passing." These physical realities are events. We can now define time as a comparison of events. Thus, we can think of time in terms of the ratios of events, such as the earth’s annual orbit around the Sun, compared to the earth's daily revolution. This is about 1 to 365. In this definition, when we are talking about time, we are talking about the ratio or comparison of events.
Consider something that appears to exist, unchanged, in relation to the Earth’s solar orbit. Assign to this a ratio 0 to 365. Our ability to measure time is based upon comparing the occurrence of one event with another. Zero in the ratio above means "no events to 365 events," Now if time is based on events, we could say that a lack of events indicates a lack of time. Comparing a zero event with a zero event gives us zero time. Consequently, the fact that something seems to exist unchanged while other things change does not mean that this thing is "floating down the stream of time." In this definition of time, things which exist unchanged while other things change have no time!
But now we can go further in the effort to make time reflect physical reality. Why not define time as events? In other words, time equals events. This divorces the concept of time from the realm of the metaphysical to the physical. This concept eliminates the idea of interval, which is associated with the comparison of events. The idea of interval must now be associated with zero events. If time equals events, then "interval" equals a lack of events. Thus, from our original definition of time, we have separated those things which give us time: events, from those things which give us no time: a 1ack of events. But now there remains the task of making what we mean by "events" reflect physical reality.
Events are changes in the physical universe, and the only real events that occur in the universe are events that occur as the motion of a body of matter or a quantum of energy through space relative to other bodies in space.
These motions through space are changes which involve energy. There are no changes in the structure of matter which do not involve motion through space by mass or energy. The vibration of molecules is a change; it is a change of position in regard to other molecules. All chemical and physical changes involve motion through space.
As an example, we can think of a jigsaw puzzle. If a piece is removed from the completed puzzle, it has undergone a change of structure. This change is the result of moving the piece through space away from the puzzle, or moving the puzzle through space away from the piece, or both. Thus to make a change in the structure of any division of matter, some matter or energy must move through space. This is true of changes occurring to the particles of an atom, the atom itself, molecules, and larger structures of matter.
Molecules vibrate inside otherwise "solid" materials. All chemical changes involve electron exchanges or sharing between atoms, and this is motion through space. All changes inside the atom involve motion through space. When a particle decays into other particles, its whole becomes parts of the former whole. All cases of whole quantities dividing into parts must involve motion through space by matter or energy.
Time can now be expressed as the equation "events = motion through space." With this in mind, we can think of an instance of time as a singular event.
Therefore, an instance of time refers to the motion through space by a body of matter or quantum of energy, relative to the motion of other matter or energy. Consequently, any comparison of instances of time, in order to arrive at a time ratio, is actually a comparison of their respective motions through space. Since a comparison of motions through space involves length (or position in regard to other objects), it follows that time and space are one! Meters and minutes measure the same thing: motion through space. This is what I believe Einstein meant when he was referring to "space-time."
But if time and space are one, what of our ability to perceive the "passing" of time? We are aware of things which have happened to us in the past. We also are aware of certain physical objects which seem to stay in a state of comparatively little change from day to day. A rock or a piece of steel may remain apparently the same for long periods of time, even though imperceptible chemical and physical changes are occurring in them constantly. The visible object remains the same or nearly the same, and this gives us our notion of "existence."
Existence then, refers to a relative lack of change, and this is equal to zero time according to the definition of time where time equals events. "A lack of change," remember, equals an interval when the concept of interval has been eliminated from the definition of time. Therefore, an interval is "a lack of change which exists between changes."
It is the observation of "a lack of change," or a lack of events, contrasted with change, or events, which gives us the illusion of time "flowing" or "passing" in a continuous stream from the past into the present. Actually what we are observing is events occurring in progression contrasted with some things which don’t seem to change.
But things change, they aren’t what they used to be, a minute, a day, a year, or an eon ago. The universe is ever—changing. There is no real future or past to which we can travel from the present. And even though it seems that we always exist in what we consider to be "the present," or things as we perceive them to be "now," these are only arbitrary designations; "present" and "now' can mean different things.
"Now" can be a day, a second, a minute, or a longer period if we care to think of "now" as meaning the present time. Time is not always something which coincides with the sequence of events in our minds, or our "stream of consciousness." Many different chemical and physical changes can take place much faster than our mind can perceive them. We can perceive some motions through space by our senses and not others.
This is the same as saying that we can be aware of the time of some things and not others, when we are thinking in terms of time equaling events. We can see things which are an inch across with our unaided eyes, but not things which are only a millionth of an inch across.
Because of our inability to ever isolate a certain pattern of things as an absolute "now," it follows that any comparison of events is going to depend upon the observer’s frame of reference, just as Einstein said. Each event can be only be considered as an isolated event if it is given a position in a progression of events.
This why it is necessary to define time as a progression of events and an instance of time as a single event. By comparing events, we establish ratios of events, and from these we derive our system of units of time. Ratios of events are based on physical reality, while the placing of an event in a sequence of events is a arbitrary mental comparison depending upon an observer.
Absolute time, a fixed moment in the existence of the universe, can now be seen as something which cannot be pinned down. How can we travel from the present to a future or past in a time machine when we can’t even pin down the present? Actually, the ideas of "future" and "past" are just convenient ways we have of thinking of the sequence of events, as is the idea of the "present." But all of these are merely our mental concepts.
None of such concepts really exist. What really does exist is the sequence of events. Our perception of the "passing of time" is actually just our perception of the sequence of events. We can’t jump into a machine and travel in our perception of the sequence of events, however!
In view of this definition of time, time machines are supremely fantastic gadgets. The universe is a dynamic and ever-changing system. Some atomic particles have half-lives of 10 x -10th, and light travels 186,274 miles in one second.
Imagine how vast the changes are which occur in the universe in one second! Now imagine a mere man-made machine capable of causing the universe to move back into a pattern it formerly occupied. The energy which would be required is unthinkable. And, where would the blueprint for this exact pattern come from?
Moving the universe into an old or a new pattern makes putting an H-bomb back together after the explosion seem like child's play.
Even if we could put an H-bomb back together, down to the last atom, this still wouldn't be moving the H-bomb back into the past. This would merely be the second time that the matter of this bomb had been arraigned in this particular pattern.
In the meantime, the rest of the universe would have undergone vast change. If this was not the case, then we could not identify any event as being a single event. If we can identify a single event, then this event can occur only once. Of course, the same type of event can occur over and over again, but not to the same object, and not in exactly the same relation to the universe as once before.
For another example, a jigsaw puzzle can be torn apart and put back together again in the same way. Each time the puzzle is put together, it looks the same as it did before, assuming that the pieces have not been soiled or damaged. The assembled puzzle is apparently unchanged, but only apparently, because all matter composed of molecules has some vapor pressure. And probably a few molecules of puzzle material jump off every now and then.
Also, the molecules are vibrating, and some chemical changes may be taking place. While the puzzle remains essentially unchanged, however, the universe has undergone vast changes, and for this reason we can positively identify each construction or destruction of the puzzle as having occurred at a certain time. No matter how many times we put the puzzle back together again, we will never do it in the same position in space relative to the rest of the universe.
Events occur in progression in our universe; the over-all pattern of things continually changes, never repeating itself. Because of this, we can think in terms of certain times in the past, which is the same as saying, "when things were such and relation to each other." The past exists only as the widely dispersed remains of an exploded bomb can be said to exist.
Coincidentally, this analogy fits the theory of the expanding universe. In this theory the universe is thought to have originated in a cosmic explosion of primal matter. The other galaxies observed to be receding from ours at near that of light speed are the products of this explosion. This theory supports the ideas of events occurring in progression and of singular events.
The case against the time machine and time travel, in this universe, should seem quite convincing by now. There is one consideration, which I have overlooked up to now, however. That is the "time dilation" effect which is predicted by Einstein’s theory. Someday soon, a satellite may be put into orbit with a highly accurate clock, such as the maser clocks, which count the vibrations of molecules.
This experiment will test whether or not the "time dilation" effect really occurs or is merely an apparent difference depending upon an observer. The clock in the satellite would be synchronized with a clock on the ground in order to detect any difference in their timekeeping, which might be caused by "time dilation."
If this experiment proves that there is an actual difference between the two clocks due to the speed of the satellite around the Earth, it will prove only that the speed of the satellite has caused the physical changes or events to slow down in their rates of change in comparison to their identical types of changes on Earth. This is the same saying that if the differences between the motions of two bodies are great enough, identical types of changes in these bodies will no longer occur at identical rates.
This would mean that a spaceship traveling at near the speed of light for many years would have its total changes (relative to those changes which would occur to it on Earth) slowed down. When the spaceship returns to Earth from a journey to another star system, hundreds of thousands of Earth-years could have occurred in the same "time" which may have only been a couple of years to the space travelers.
Then, if the "time dilation" effect is found to occur, the actual consequences of it would be to slow down the lives of humans aboard such spaceships in regard to the lives of humans left back on Earth. The effect of "time dilation" would be similar to that of suspended animation. In regard to people left back on Earth, one could take a short ride in a spaceship traveling at near the speed of light and come back to Earth to find that a great deal of time had passed. But this would not be traveling in time as it is ordinarily envisioned. It would be traveling in time, however, if we care to think of time as motion through space.
Events on the spaceship would be occurring more slowly than events back on Earth. Before the spaceship left the Earth, events on the ground and in the spaceship which were identical occurred at identical rates, and they had the same time, a ratio of 1 to 1. As the spaceship left the Earth and it began to accelerate towards the speed of light, the ratio of one Earth event to one spaceship event would begin to change depending upon the velocity of the spaceship. The ratio would become a fraction of a spaceship event for each event on Earth.
The time of the spaceship, and the people in it, would be slowed down in comparison to time on Earth. The spaceship and the Earth could be thought of as having different times or different time systems. "Different time systems" is better because of its similarity to "different physical systems." This designation could be applied to bodies traveling away from each other at a rate high enough to cause observable differences in the rate of physical changes or events between the two systems. Of course, all of this does not add up to travelling in time as imagined by those who thought they were writing science fiction when they wrote about going to the past or future.
Even though physical changes which are identical on the Earth would occur at different rates on the Earth and a spaceship traveling at near the speed of light, thus giving the Earth and the spaceship two different "times": events in both systems would continue to progress. Therefore, a spaceship traveling near the speed of light will not serve as a time machine if the "time dilation" effect is found to occur. The passengers of the spaceship would not be travelling into the future by making a trip through space at near light speed; they would only be prolonging their existence in regard to the Earth.
With all of the possibilities of time travel ruled out, at least in this universe, writers of science fiction should resort to other means of placing their heroes from our time into an exotic future world of super science. There are several alternatives, such as having the hero go for a ride in a spaceship at near the speed of light to return to the Earth thousands of years later. Even though this Earth would be "the present" to the hero, it is our "future."
Another good device is merely to write about alternative or other universes, which have developed similar to ours, which contain an equivalent to our Earth. This other Earth can be ahead or behind ours in history. Then too, there is always the possibility of suspended animation as a means of sending a hero into the "future."
But please, fellows, let's have no more time travel stories in the tradition of H.G. Well's "The Time Machine" labeled as science fiction!
(Posted to the Web November 10, 1999. Unpublished essay written October, 1959, based upon earlier published article "No More Time," published in a science fiction fan magazine, Canadian Fandom, June, 1954.)
Any comments? Send e-mail to: William D. Conner
Copyright, 1999 by William D. Conner, all rights reservered.