Like most people, you may believe that time travel is impossible. Actually, every day, twenty-four hours a day, we all travel through time...in the direction of the future. Of course, this isn't the type of time travel that you imagine. Rather, we want to think of real time travel as a dramatic leap to the future or past using a time machine--and we don't usually believe that it can happen.
In fact, the idea of real time travel has intrigued many scientists, (including Thomas Edison) not to mention many authors and screenplay writers. But, although many characters in books and movies rely on time machines, real time travel doesn't seem to work that way. Einstein's Theory of Relativity explains why time machines would have to be complicated (and perhaps impossible-to-build) devices.
So--is time travel impossible then? Real time travel seems to be possible "with or within the mind," according to author John Gribbin. He writes that time warps do exist, but traveling through them doesn't involve the use of a special machine-other than your own mind.
Real time travelers recount using much more normal travel means. First, many people have visited another time or place in their dreams. Others have said that they somehow "saw" another time. Finally a few people even claim to have lived in another time--during an earlier life; whether their claims are true, though, is another matter.
Psychologists, parapsychologists, and other researchers have a technical name for backward time travel. They call it retrocognition, which simply means "knowledge about the past."
Retrocognition occurs when a person somehow "travels" to the past. A retrocognitive time traveler does not roam through history, selecting interesting historical figures to meet. Rather, a real time traveler to the past simply peers into a past time--as an observer. Most times, the person does not even see events that were historically important, but peeks back at places or experiences of no particular significance.
Here's a common retrocognitive experience, as reported to researchers Celia Green and Charles McCreery. A man named Ronald Dawson decided to revisit his hometown after a long absence. Much of the downtown area had been torn down since his childhood and rebuilt. But as he drove his car down the main street, he saw a little store where he used to shop as a child. Mr. Dawson told Green and McCreery:
I was delighted to see it and parked the car opposite. As I turned to cross the road it just wasn't there. I cannot exactly say that I saw it go, it just was not there, although I had seen it clearly.
Notice that he didn't see any people, and he didn't observe any other changes. But the sudden appearance and disappearance of the store points to the possibility of time travel.
Unfortunately, the biggest problem with retrocognitive time travel is that people can't prove that they actually traveled to the past. For example, Mr. Dawson had only his own testimony to prove that he had seen a store from his childhood. After all, he hadn't walked into the store and picked up a few items to bring back to the present as proof that the trip took place.
Whenever someone claims to have traveled to the past, there are three possible ways to account for the experience:
The person may be lying. Although that doesn't seem to happen often, it's the first thing a time travel detective will check.
The person may have made a mistake about what he or she saw. Perhaps Mr. Dawson was tricked by his own eyesight. He might have seen something out of the comer of his eye that reminded him of the store. He may have had no intention of lying; he was simply mistaken about what he saw.
The person may have had a true retrocognitive experience. If the person had a reputation for telling the truth and has never had other strange experiences, people may choose to believe the story. But anyone who believes his story will be doing so without factual evidence that the time trip took place. Of course, anyone who believes that the trip didn't happen will also be unable to prove that it didn't take place. Believing and knowing are very different from each other and should never be confused.
According to people who claim to have taken retrocognitive time trips, you may see people and buildings from past times. You may be aware that the weather has suddenly changed. You may see many things that no longer exist in the present. But you will not be able to touch or pick up any objects you see. And the people you see in the past will not speak or even see you. They exist in their time, you exist in yours--and the two never seem to interact.
This is quite a different picture from the one presented in the movie Back to the Future and its sequels. Not only does Marty interact with everyone he meets in the past, but he also interferes with history to the extent that his brother and sister become "erased" from the future. In real time travel, no such possibility exists.
Retrocognition is very similar to the experience of seeing a ghost of the dead. Suppose that you are walking down the street when you see the ghost of a neighbor who died a year ago. If you have read much about ghosts, you will know that they are not the scary phantoms that many people think they are. The neighbor's ghost may be walking in her garden or sitting on the front steps of her house or standing on the front lawn, gazing into the distance--something she may have often done. As you see her ghost, you are glimpsing a kind of "video replay" of a past moment in that woman's life. You are in the present time, but somehow and scientists don't know how a part of her life has become visible for a moment.
Traveling back in time is similar, except that instead of seeing a person's ghost you are seeing the ghost of a past event or place. Suppose, as you step out of your house one morning, you are aware of an eerie silence. Then you notice that many of the houses on your street are gone; you see woods instead. You hear the sound of a horse's hooves coming down your street--only it's not the street you saw yesterday. It's not made from cement or asphalt; it's now made from cobblestones or hard packed dirt. You see a man and a woman leave a nearby house, dressed not in today's clothing, but in clothing from the early 1900s. A man in a horse drawn wagon stops in front of their house to deliver a block of ice.
Instead of just seeing one person's ghost, you have stepped out your door and momentarily entered the past. In a few moments, though, it will all fade from view, replaced by the present.
Travel to the future is called precognition, or "knowledge of future events before they happen." You can travel to the future to gain a glimpse of what will happen to you, usually, or to someone you know. You won't find yourself beaming aboard the Starship Enterprise, though, or even the space shuttle Endeavor. Neither will you find yourself in some future city trying to find or avoid a "terminator."
Here is an example of a real precognitive experience. Mrs. Appleton, according to author Brian Inglis, had a recurring vision when she was a child. At bedtime, she frequently saw in her mind a young boy wearing a sailor suit. In the scene that she pictured, the boy was always standing on a roof, holding a tomato plant. He would smile at her, and she would find herself smiling. She had the vision until the day her mother died, and she was placed in an orphanage. From then on, the vision never reappeared.
As an adult, Mrs. Appleton married an optician and lived a happy life. One day, after she had been married fifteen years, her husband brought home a photograph album that contained many pictures from his childhood. Since she hadn't seen many photos of him as a child, she eagerly looked through the book.
As her eyes focused on one picture, "my heart stopped, and I felt physically ill," she wrote. "There in front of me was the little boy from my childhood."
The photograph showed her husband as a young boy: wearing a sailor suit, standing on the roof of an apartment building. Although he was not holding a tomato plant, one was beside him on the roof.
Why had she seen a vision of her future husband as a child? Was this a peek into the future by peering into the past? Or did she have a vision of the day that she would see the childhood picture of her husband?
"For so long I have felt alone with my story, not daring to discuss it fully with anyone for fear of being thought a crank," she wrote author Inglis. "I have never told my husband."
Another typical precognitive experience--and one that came true in a much shorter period of time--happened to an air-conditioning contractor living in Idaho, according to researcher Louisa Rhine. One night he dreamed that he was working all night in a hardware store. As the sun came up, he. picked up his toolbox and walked toward the front of the store where the sunlight was streaming through the plate-glass windows. When he reached the front door, he turned around and looked at the rear of the store. There he saw two large air conditioners hanging from the ceiling. When he woke up, he remembered his dream because, as a person who installed air conditioners, he had never seen any hang from the ceiling.
Three weeks later, his dream began to come true. The owner of a hardware store asked him to install two air conditioners. Because there was no floor space available, they would have to hang from the ceiling. What's more, so that the installation wouldn't disrupt business, they would have to be installed at night. The night that he installed the units, the man finished around 5 A.M. He picked up his toolbox and walked to the front door, where he saw bright sunlight illuminating the store. He glanced back at the store and saw the two air conditioners suspended from the ceiling. He was chilled by the knowledge that three weeks earlier he had somehow visualized everything that happened that night.
Did this really happen to him? The reader must take his word for it, since he didn't follow some easy steps to prove that his dream was precognitive. He would have given good evidence that he visited the future in his dream if he had written down his dream and if he had told it to someone--before he walked into the hardware store and realized that his dream was coming true. But this points out an important fact about precognitive dreams: They often provide a glimpse of an unimportant event, so unimportant in fact that the dreamer may not think that the dream is worth remembering.
The most common type of time travel involves a trip to the future. Getting a glimpse of the future is reported much more often than stepping into the past--even momentarily. Thousands of people have precognitive dreams or visions each year, but only a few claim to have visited the past. Many more experience what is known as déjà vu (which means "already seen" in French), a sense that they have visited a place or experienced an event before it actually occurred.
Is future travel easier? Actually, precognition may not be an easier process than retrocognition. It may simply be that it's easier to get others to believe your trip to the future. If you write down what you see and give it to someone before the future event occurs, people will believe you. On the other hand, tell people that you've visited a time in the past and seen the Battle of Bull Run and they are more likely to laugh or to think that you've gone crazy. Since there's no way to prove that a time trip to the past was real, many people may choose not to tell anyone about it.
Although time travel is usually pictured as a great adventure and although it can be enjoyable to imagine, it is not always fun in reality. In fact, travel to the past is usually a confusing experience. If you see a past time or event, how can you be sure that it really occurred and that you did not imagine it? How can you convince other people to believe you? Trying to talk about your experience can be frustrating if no one believes you.
Travel to the future can be unpleasant, too. H. G. Wells imagined future time travel in his time machine to be similar to riding a "switchback" or roller coaster. The time traveler felt as if he were going to crash at any moment. His eyes hurt as night and day flashed by.
Although real travel to the future has not had the same physical effects, its emotional effects can be upsetting, especially if your dream or vision allows you to have foreknowledge of a tragedy. For example, author Cassandra Eason has written about the experiences of a girl named Pat who saw the future in a dream and was blamed for it. When she was thirteen, she had a dream about someone at the bottom of a nearby lake. The next morning she told her mother about the dream, but her mother wasn't interested in listening to her story. As Pat told Eason, her mother "sent me off to school and told me not to be stupid."
That afternoon, her mother yelled at Pat when she returned home. Angrily, she told Pat that her cousin--an older woman with failing eyesight had drowned that day. She had gone for a walk around the lake and had stepped on some algae growing at the lake's edge, thinking that it was grass.
"Your bloody dream," her mother repeated over and over again, as if Pat's dream had caused the events rather than merely pictured their occurrence.
As you see, time travel appears to be possible, but perhaps not in the ways you have imagined. Rather, to make a time trip, all you'll need is your brain and some luck. But before you pack your bags and say "bon voyage," you need more information about the types of time trips people have taken.
Copyright © James M. Deem. Adapted from How to Travel Through Time (New York: Avon, 1993). All rights reserved.