Time Travel and Science
Whether or not time travel is ever achieved, interest in the subject seems unlikely to diminish in any future we can imagine. In fact, it is difficult to envision a time in which visitors from another time would not cause a stir or get themselves arrested.
Aside from ABC’s Lost, where the cast is totally out of sync with time as we know it, a brand new HBO/BBC film comedy Frequently Asked Questions About Time Travel explores the humor possibilities in the burning enigma suggested by the possibility of a time warp in the men’s room of your favorite pub, but even serious people think about time travel. Popular physicist Michio Kaku in his current bestselling book The Physics of the Impossible explores to what extent the technologies and devices of science fiction, including time travel, that are deemed impossible today, might well become commonplace in the future, just as lasers, televisions, atom bombs, and other familiar technologies of contemporary life were once deemed impossible. Kaku says a time machine is consistent with the known laws of quantum physics, although, he thinks it would take an unbelievably advanced civilization to actually build one.
British cosmologist Stephen Hawking has suggested that the absence of tourists from the future could be taken as evidence that time travel, at least to a designated time in the past, is not going to be achieved; though Carl Sagan once argued that such tourists might actually be here but just not talking. If they were talking they might have difficulty staying out of trouble. In fact not a few homeless people have reported being visitors from the future. How do we know they are not?
For some, one of the most plausible explanations for UFOs is that they are time machines from some future world. We’ll leave you to devise your own theory, and toward that end we thought you might benefit from this summary of some of the relevant speculation on the subject from David Childress, editor of The Time Travel Handbook.—Editor
Practical time travel continues to elude the consumer, and until time travel devices are manufactured on a large scale, the garage inventor will just have to build his own.
From the early time travel experiments of Keely, Tesla, the Wilson Brothers of EMI/Thorn, and others, to the modern time travel allegations of the Philadelphia Experiment and the Montauk Project, we would like to bring practical time travel to the consumer.
Posted on the Internet recently was this commentary by someone identifying himself as Brian X. We thought it made many good points and include it here:
Imagine, if you will, that you are one of the people still alive today that was born prior to 1903, when the first airplane took flight. When you were young, the idea of flying would probably have been quite exciting. Some scientists believe that we may presently be living through an identical scenario. The thing that would be so exciting, however, would not be flight but time travel. Leading scientists believe that our children will live to once again see the impossible become routine.
Professor Michio Kaku of the University of New York believes that space flight may one day unlock the secret of time itself. This will require the development of spacecraft that can travel at speeds on the order of two hundred million kilometers per second, that’s about six hundred million miles per hour. Craft traveling at this speed will take us near the speed of light, where time actually slows down. This is what’s known as time dilation. Einstein’s theories predict that the faster a spacecraft moves, the slower time ticks inside of it. Imagine that a rocket ship takes off from earth and approaches the speed of light. If we were to watch it from earth with a very powerful telescope as it traveled away from us, we would see everyone inside the ship as being frozen in time. To us their time would slow down, but to them nothing would change!
This has been measured in the laboratory and on location using atomic clocks, aircraft, satellites, and rockets. It is proven that time slows down the faster you move. In 1975 Professor Carol Allie of the University of Maryland tested Einstein’s theory using two synchronized atomic clocks. One clock was loaded on a plane and flown for several hours, while the other clock remained on the ground at the air base. Upon return, the clock on board the plane was found to be ever so slightly slower than the one on the ground. This was not due to experimental error and has been repeated numerous times with the same result. This difference in time is even more pronounced in satellites such as the space station. This is because these objects are traveling at speeds much faster and for much longer periods than possible in an airplane. The faster an object moves, the more time is distorted.
Now that we know that it is possible to travel into the future by moving at great speeds, the next problem is how to travel in time a respectable amount without having to sit in a fast-moving spaceship for years. This problem is solved by the theoretical existence of what are known as closed, time-like curves and wormholes. Einstein’s special and general theories of relativity combine three-dimensional space with time to form four dimensional space-time. Space-time consists of points or events that represent a particular place at a particular time. Your entire life thus forms a sort of twisting, turning worm in space-time! The tip of the worm’s tail would be your birth and its head is the event of your death. The line which this worm creates with its body is called that object’s world line. Einstein predicts that world lines can be distorted by massive bodies such as black holes. This is essentially the origin of gravity, remember. Now if an object’s world line were to be distorted so much as to form a loop that connected with a point on itself that represented an earlier place and time, it would create a corridor to the past! Picture a loop-to-loop track that smashes into itself as it comes back around. This closed loop is called a closed time-like curve.
Wormholes are holes in the fabric of familiar four-dimensional space-time that are connected but which originate at different points in space and at different times. They provide a quick path between two different locations in space and time. This is the four-dimensional equivalent of pinching two pieces of a folded sheet of paper together to make contact across the gap. Distortions in space cause the points separated by the gap to bulge out and connect. This forms a wormhole through which something could instantaneously travel to a faraway place and time. No more problems of traveling in a rocket ship for years to get into the future!
This is essentially what was written about in “Alice in Wonderland’s Through the Looking Glass.” Her looking glass was a wormhole that connected her home in Oxford with Wonderland. All she had to do was climb into her looking glass and she would emerge on the other side of forever. In reality, however, it would require a much more elaborate scheme to create a wormhole that connects two different points in space-time. First, it would require the construction of two identical machines consisting of two huge, parallel metal plates that are electrically charged with unbelievable amounts of energy. When the machines are placed in proximity of each other, the enormous amounts of energy—about that of an exploding star—would rip a hole in space-time and connect the two machines via a wormhole. This is possible, and the beginnings of it have been illustrated in the lab by what is known as the Casimir Effect. The next task would be to place one of these machines on a craft that could travel at close to the speed of light. The craft would take one machine on a journey while it was still connected to the one on earth via the wormhole. Now, a simple step into the wormhole would transport you to a different place and a different time.
Wormholes and closed, time-like loops appear to be the main ways that time travel into the past would be possible. The limitation on this time travel into the past is that it would be impossible to travel back to a time before the machine was originally created. Although the aforementioned theories of general relativity are consistent for closed, time-like curves and wormholes, the theories say nothing about the actual process of traveling through them. Quantum mechanics can be used to model possible scenarios and yields the probability of each possible output. Quantum mechanics, when used in the context of time travel, has a so-called many-universe interpretation. This was first proposed by Hugh Everett III in 1957. It encompasses the idea that if something can physically happen, it does in some universe. Everett says that our reality is only one of many equally valid universes. There is a collection of universes called a multiverse. Every multiverse has copies of every person and all matter…
The proposal of time travel is backed by scientific theory, but that is not enough to make it realistically possible. Numerous arguments are proposed that prevent time travel into the past. Both common sense and scientific fact construct serious obstacles. A major argument against time travel into the past is called the autonomy principle, better known as the grandfather paradox. This paradox is created when a time traveler goes back in time to meet his or her grandfather. Now, upon their introduction, it would be possible to change the course of events that lead up to your grandfather and grandmother marrying. You could tell him something about a family secret to convince him you are who you say you are, and he may proceed to tell his soon-to-be wife. She may in turn doubt his sanity and have him committed. Thus, your grandparents would never have your mother, and thus you couldn’t be born! But then, how could you have ever existed to travel back in time if you don’t exist?
Another argument of impossibility is called the chronology principle. This principle states that time travelers could bring information to the past that could be used to create new ideas and products. This would involve no creative energy on the part of the “inventor.” Imagine that Pablo Ruiz y Picasso, the most influential and successful artist of the 20th century, were to travel back in time to meet his younger self. Assuming he stays in his correct universe, he could give his younger self his portfolio containing copies of his paintings, sculptures, graphic art, and ceramics. The young version of Picasso could then meticulously copy the reproductions, profoundly and irrevocably affecting the future of art. Thus, the reproductions exist because they are copied from the originals, and the originals exist because they are copied from the reproductions. No creative energy would have ever been expended to create the masterpieces!
A notion that was once nothing more than science fiction is now a concept that’s becoming reality. Einstein’s theories of general and special relativity can be used to actually prove that time travel is possible, and research has shown that fast-moving craft can travel into the future. Time dilation is the easiest method because it merely requires high velocity motion to experience time travel. Phenomena known as wormholes and closed, time-like curves are possible means of time travel into the future and the past. Traveling into the past is a task which is much more difficult, however. Its theory involves complicated scenarios of tears in four-dimensional space-time, energy equivalent to that of an exploding star, and traveling near the speed of light. Both common sense and scientific fact can be used to paint scenarios that become serious obstacles. Yet even these hindrances can be explained away! If the multiverse concept is reality, then most present ideas of time travel are based on a false reality. If time travel is completely impossible, then the reason has yet to be discovered. Excerpted for Atlantis Rising by the editor from The Time Travel Handbook from Adventures Unlimited Press.