Time Travel The Possibilities, Challenges & Potential Introduction to Astronomy Dr. Vishnu R. Khade, Ph.D/MBA
A Collaboration by: John, Chris, Elana, and Marci
Have you ever imagined traveling through time? Many of us have. The effects of time travel are numerous. Imagine traveling to the future and seeing your children or grandchildren as adults or traveling back in time to be with a friend or relative that has passed on in the present. Along with the joys time travel could bring, we must be aware of the dangers such as the “grandparent paradox.” Going back in time may open the door to change the future. If a person were to eliminate another person by traveling back in time, would this alter the existence of people in the future? Are there safeguards in the universe to prevent this from happening? A certain law of nature yet to be discovered perhaps.1 Some interpretations of quantum physics state that every time there is a choice in the universe it takes both of them and splits into two separate new universes.2 Could there be parallel worlds and how would one ever find their way home? Time travel can result in both positive and negative effects. Until we have the answers, we will continue to explore the possibilities. For this reason, throughout history, physicists have explored the concept of one-day achieving that goal.
What is Time? When did Time Begin? What is Space?
In order to understand the potential of time travel, we must first understand what time is. Many consider time to be a period during which an action or event occurs; also a dimension representing a succession of such actions or events.3 According to David Anderson, Ph.D (an excerpt from his video documentary), “The answer is close, but very elusive.” Time hides right in front of us…in our philosophy and religion…in our science fiction and science fact…in our art and folklore…in our mathematics and physics… and in our own spirit and mind. Another
http://www.time-travel.com/whtitrip.htm http://www.time-travel.com/istitrpo.htm 3 Time Travel Research Center: http://www.time-travel.com/timeintr.htm
question that comes to mind is, “When did time begin?” Theorists have attempted to explain the beginning of time. Maybe time began with the Big Bang theory or maybe it began with the birth of religion. There are no defined answers, but hopefully, we can challenge your thoughts and opinions on the mystical and often enticing, yet elusive answers. The definition of space is equally challenging to physicists across the globe. According to Alexander Friedmann of Russia, space has no boundaries, but is not infinite; it can be measured. “Spacetime”, the concept from special relativity that space and time are both essential in describing the position, motion, and actions of any object and event are best explained by Albert Einstein.4 The connection between motion and clocks mean that space and time cannot be considered as two separate concepts but as one entity. What is the purpose of Einstein’s theory of special relativity? He wanted to establish the similarities of the reproduction of light and the validity of the physical laws in all frames. He proved that light does not obey the ordinary laws of relative motion so it is impossible to gain on light. The consequence of this is that time intervals, distances, and the timing of events will be different for observers at different speeds. This is where the famous E=MC2 comes from. However, Einstein did not take into account the effects of gravity which he later does in his theory of “General Relativity.” John Wheeler gave the best explanation of general relativity when he said “Space-time grips mass – telling it how to move, and mass grips space-time – telling it how to curve”.5 As researched by our group, there are numerous theories of time travel. From Einstein’s theory of space and time, to the “Kerr Solution,” the first mathematical example of a time machine, the possibilities are endless. The “Kerr Solution” is an explanation for black holes that explain all that exist in nature. Roy Kerr proved that they are rotating spheres with a ring singularity surrounded by a gravitational field. They have mass and angular momentum around an axis of symmetry.6 This was after the “Schwarzchild Solution” was proposed. Karl Schwarzchild tried to prove they were perfectly spherical and non-rotating with a point of mass of no height, width, or depth of infinite density. In the center is a singularity surrounded by a gravitational field where space and time stop. The problem was that stars rotate. It was not until the 1970’s when astronomers discovered what appear to be real black holes in our galaxy and in the hearts of
Discovering the Universe; Neil F. Comins & William J. Kaufmann III http://library.thinkquest.org 6 http://library.thinkquest.org/25715/types/kerr.htm
other galaxies. The theory of relativity allows for time travel at very high speeds. Theorists have long suspected that black holes and white holes are connected by wormholes. What does this mean to the future of time travel? How will scientific exploration affect our lives today and in the future or possibly the past? Time Travel – The Possibilities & Potential “The Dilation Theory” One theory discussed regarding the possibilities for time travel is the time dilation theory.7 In order to validate the precise findings of this theory, the experiment requires a fast moving object traveling for long periods of time to respectably achieve the goal of time travel to the future. In 1975, Professor Allie of the University of Maryland synchronized two atomic clocks. One was placed on an aircraft and the other remained on the ground. When the plane returned to earth after several hours of flight, the clock inside the plane was slightly slower than the one that remained on the ground. This experiment was tested several times with the same result. Objects such as satellites, which travel at much faster speeds and for longer periods have shown an even more pronounced distortion of time. Similar experiments have been tested over the last twentyfive years with astounding conclusions; time travel is possible. “The Circle of Lasers Theory”
The key to time travel may be unlocked with the recent experiments of Professor Ronald L. Mallett, a physics instructor at the University of Connecticut.8 Professor Mallett believes he has found the secret to time travel through the use of a ring of circulating laser beams. The professor’s theory involves stepping into a circle of light and teleporting to another place in time. He also believes he has the mathematics to prove his theory. As incredible as it seems, Professor Mallett hopes to develop a time machine that will transport subatomic particles such as neutrons through time within the next ten years. His ideas are the result of focusing on light rather than matter. He bases his theory on Einstein’s theory of relativity, which states, “gravity is the curvature of space-time.” Light has no mass or weight so nothing can travel faster then light.
Brian’s View on Time Travel and Interdimensional Voyage Grace E. Merritt, “Time Travel with Light,” The Hartford Courant”
Light also is effected by gravity because it has momentum and energy.9 This means that when a strong gravitational pull increases enough, a threshold is reached where time becomes space. Moving in space could allow you to go forward or backward in time. Professor Mallett’s theory addresses the concept of time moving in a straight line. His theory discusses the possibility of bending the circle of lasers to go to the past or the future by forming a laser beam into a circle, a gravitational field would be formed. The gravity of the light circle causes a twisting of space. He will then circulate two lasers in opposite directions to create a ring of light. Intensifying or slowing down the light would cause the gravitational field to intensify, which would curve space-time. Many of his colleagues believe he is onto something. His critics however, are doubtful because he has not published information on his experiment involving light. For the time being, the professor’s theory remains untested. “Wormholes”
What about the possibility of time travel without traveling fast for multiple years? Many physicists have studied and documented their findings concerning wormholes. To travel through space and time without being on a spacecraft for several years would require the construction of two identical machines, which together could create an amount of energy equal to that of an exploding star when placed in close proximity of one another. This energy would rip a hole in space-time, which would create a wormhole between the two machines. This is called the Casinir Effect. The beginnings of it have been demonstrated in labs. The next step would be to place one of these machines on a craft traveling near the speed of light while it is connected to the one on Earth via the wormhole. A simple step into the wormhole would transport you to a different place and time. “Humans have long been aware of the cyclic nature of time in the regular way that night follows day and the passing of the seasons. We are also aware of the linear nature of time flowing from past to future. Events that are now in our past will remain there never to return, but will recede further and further back.”10 Bodies moving freely at constant velocities and in the absence of
http://library.thinkquest.org Black Holes, Worm Holes, and Time Machines,” Jim Al-Khalili
gravity are described by special relativity. Once the force of gravity is switched on, we must turn to general relativity. Newton’s law of gravity is only an approximation to the more exact general relativity. Newton’s laws of motion are only approximations to special relativity. For most purposes in everyday life, the accuracy of Newton’s mechanics is as much as we need. The differences show up when objects move at very high speeds, which is what we would need to move forward or back in time. There are two major questions of special relativity. First, Why can nothing travel faster than the speed of light? In addition, why do clocks tick more slowly when they are moving fast? The speed of light is a two-way barrier; nothing moving slower than light can ever go faster than light and nothing already faster than light can slow down to a speed below that of light. Hypothetical “superluminal” particles that travel faster than light are called tachyons and if they exist, would be traveling backwards in time. ( time slows down at high speeds and stops at the speed of light; tachyons faster than light would be traveling backwards in time)
If a spacecraft could travel close to the speed of light, then it sees the distance it needs to cover contracted. According to the astronauts aboard, a journey to a star one thousand light years away might only take a few years. The catch is, due to the effects of time dilation, the journey would still take over 1,000 earth years. After all, as seen from earth, the spacecraft is moving below light speed. On earth, we would see the craft having to cover the entire uncontracted distance, but we would also see the craft’s clock slowed down, therefore, we would also agree with the astronauts on the amount of time the journey took. In principle, you could travel across the visible universe covering billions of light years in one day without ever reaching the speed of light. This is despite the fact that light, which is moving faster than you, takes billions of years to make the same journey.
Natures Time Travelers There is another concept involving time travel. It involves suspension of time.11 Nature has been using time travel for millions of years using suspension of time. Seeds are a prime example. Seeds such as the lotus plant last as long as 2,000 years and still germinate. Spores and
Death and Time Traveling
microbes have remained suspended in time for millions of years before they come to life. Insects suspend their lives while in the nymph stage. They emerge later, literally time-jumping past the life span of possible predators. Another example is frogs. They can go through the winter with one-half of their body’s fluid turned into ice and emerge in the spring. Imagine freezing a human being in the year 2001 and “thawing the body” in the year 3000. Possible? Definitely! In a sense, that is time travel. The preservation of a human life in one century only to emerge in another.
The Einstein - Rosen Bridge Theory A New Zealander by the name of Roy Kerr used Einstein’s equations of gravity, but there was a quirk to the solution. If one fell into a black hole, they might be sucked into a tunnel and shot out of a white hole in a parallel universe. This theory was known as the Einstein-Rosen Bridge theory. Einstein and collaborator, Nathan Rosen, published a paper to attempt to prove that Schwarzschild’s singularities did not exist. They re-wrote his mathematical solution so it did not contain a point where space and time stopped. They showed that the singularity became a bridge connecting our universe with a parallel universe. For Einstein, it was a purely theoretical experiment in geometry in which two spacetimes would be joined together. In the movie, “Alice in Wonderland,” Alice is using the Einstein-Rosen Bridge into another universe. The reason strange things could happen in Wonderland was because the laws of physics were different in that universe. The story was based on ideas about how space could be curved and how two spaces could link together in a higher dimensional hyperspace. What Einstein showed fifty years later was that such curvature of space occurs wherever there is a strong enough concentration of energy. His theory of gravity (general relativity) provided the basis for such tunnels to other worlds although they were not likely to exist. One way for an Einstein-Rosen Bridge to form is for a singularity in our universe to attach itself to a singularity in a parallel universe. What is wrong with this concept? The event horizon. Once you jump into a black hole, you cannot come out unless the black hole is connected to a white hole. However, a white hole must be surrounded by the opposite of an event horizon (an antihorizon), which would allow traffic out but never in. Unfortunately, anti-horizons convert to normal horizons mere seconds after formation. Ultimately, after passing through an event horizon of a black hole, you would find
that there is a second event horizon blocking your exit at the other end. These bridges are highly unstable and survive only a fraction of a second before “pinching off.”
How to Build a Time Machine
Scientists have already proven that according to Einstein and the general theory of relativity, there is nothing to prevent time travel. However, there have been attempts to disprove this. Kip Thorne of Cal-Tech tried to prove time travel was not possible. He studied the situation from all sides and came to a startling conclusion. There was nothing to prevent time travel. When Carl Sagan was working on his novel “Contact,” he wanted to be as scientifically accurate as possible. He went to Kip Thorne and asked for a solution to time travel where the speed of light was not a concern. Kip and his colleagues willingly attacked this problem. They did research on it, but tackled the problem backwards because it was only for a fictional story. They came up with an actual way to build a time machine. There are two chambers each, with two parallel metal plates. An intense electric field is created between the two that rips the fabric of space-time. This event creates a hole in space that links the two chambers. One chamber is taken on a long fast journey close to the speed of light while the other stays where it is. Time would pass at two different rates at the two ends. Going through one end would send one to the past or future as they came out the other end. The only problem with this solution is that it would cost more then the gross national product of the entire planet earth to build.
A Final Thought There is a fascinating book written by Robert Heinlein concerning time travel. In “All You Zombies,” there is a woman born in 1945. She meets a man in 1963 and becomes pregnant. She has the baby nine months later, but there is a problem with the delivery. She loses her female organs and actually becomes a man. To make matters worse, someone steals the baby from the hospital. The person who had the baby becomes very depressed and becomes a wandering alcoholic. One night in 1970 the person goes to a bar and meets the owner, who has a time machine. The person uses the machine to go back to 1963 where he meets a young girl and gets her pregnant. He then goes forward 9 months and steals the baby, then goes back to 1945 and
drops the baby off. He then goes to 1985 with the bartender who stays there. For the last trip, he goes back to 1970 and opens a bar. He actually ends up being his own mother, father, bartender and so on. This strange story shows what sorts of things may be lurking in places we have yet to go.
Conclusions and Why it is Important to Know Information about Time Travel At this point in time, the challenges that face physicists world- wide are numerous. Whether it involves traveling beyond the speed of light, to understanding the dynamics of a black hole or wormhole, the risks of losing human life remain a reality. In conclusion, we believe time travel is possible. It may take many years or centuries before it becomes a reality, but the physicists have begun the journey. Many years ago, people only dreamed of traveling in space. Today, that dream is a reality. There is no doubt that time travel is possible. We have all read or watched movies that enlighten the possibilities. From the most renown story of time travel by H.G. Well’s classic “The Time Machine” to the movies “2001, A Space Odyssey” and the Nostromo in “Alien,” our curiosity is piqued. Imagine if we could travel to the future and unlock the secrets to curing diseases such as cancer, leukemia, diabetes, and aids, to name a few. We should however, be concerned about the ramifications of time travel. We must fully understand many paradoxes before we choose to continue this area of science. The grandfather paradox for example, should be at the top of the list of concerns. Do we risk altering life, as we know it? Finally, even with the simplicity of the physics involved, unfortunately, the technology does not yet exist to achieve practical time travel for large biological life forms such as humans at this time. Why should we continue to explore the information about time travel? The answer is simple. Knowledge is the key to advancement. Our group agrees that we must be cautious when studying the possibility of time travel. We must fully realize the consequences of our actions before we pursue such an endeavor. However, there are many benefits to the concept. Where there is uncertainty about our future on earth, there is hope for a new world. Whether we travel to the past or the future, we will have the knowledge to overcome what the future holds. For the time being, physicists hypothesize and speculate on time travel, it comes simply to that. Speculation.