Is Time Travel Possible?


How many times have you said, “If I could do this or that again that you would do it differently?” I know I do and I said this statement from time to time when something does not go according to plans. Then I start thinking about what if I can build a time machine and go back in time just simply to change a decision that I might have made to cause something to go wrong.

Stephen Hawking, world renowned cosmologist, and many physicist believe time travel or temporal displacement is possible but the main problem with moving through time is that it will take a lot of energy to make it happen, especially if they want to sent something as large as a human forward or backward in time. But It is very easy to do this with sub-atomic particles in an accelerator as we will see later.

The Time Tunnel TV Series
The Time Tunnel TV Series

The View of Time Travel in Science Fiction Movies

We have seen many movies of time travel such as the sci-fi classic Time Machine”, the TV series of the 60s, The Time Tunnel and more recent movies The Time Traveler’s Wife and “Back To the Future” movie trilogy. These were all good movies in their times but they never quite explain why time traveling needs so much power to sent something back and forth across the time continuum or even how it was done.

In these movies you always saw a lot of fancy equipments with lights, dials and gauges to dramatize the power of time traveling and the person would disappear in a blink of an eye. Today physicist can explain how it is possible to travel through time based on what they learned from particle physics and black holes because of Einstein’s papers on relativity.

A Timely Definition

From a physicist’s viewpoint time is defined as one of the four dimensions in our physical world. Everything that exists in the universe has length, width, height, and the fourth dimension called time. When we are moving around in the world we always move in these four dimensions and everything in the universe does the same thing down to the atoms and sub-atomic particles that all matter are made of.

Time is in essence the existence of something in the universe and it is basically another dimension in length. Look at it this way, each one of us will be around for 70 to 100 years, the pyramids will be around for about couple thousand years more, and the earth and sun will exist for a few billion years more.

The Pyramid of Giza
The Pyramid of Giza

Fundamentals of Physics

Mass And Time Connection

Physicists have known for a while that time slows down near massive objects. It was clarified in Einstein’s paper on Special Relativity when he first published it in 1916 that mass put a drag on the flow of time. This is called the time dilation effect.Think of time, as water flowing in a river, the speed of the flowing water will slow down around large boulders in the river. This phenomenon is happening all the time on earth when tourists are standing near the giant Pyramid of Giza in Egypt. This is the most massive structure on the planet with an estimated mass of 40 million tons.

Time slows down near the pyramid due to it large mass but the effect is small. However, if you were to exaggerate this effect, an observer looking at the pyramid would see people moving slower near the pyramid with respect to himself and if an observer standing near the pyramid were to look out toward the desert he would see people moving along quicker with respect to himself. In this exaggerated scenario, if he stood there long enough he would emerged a few minutes, hours or even a day into the future depending on how long he stood there while time away from the pyramid is zooming by faster than his time.

This drag on time also occurs near the Earth's surface. Time moves slower at the surface compared to the flow of time measured at a distant of 100 or even 200 miles above the Earth's surface. The Earth is a massive object in space causing space to curve near it. This theory of Einstein was proven many years ago with a specially design gyroscopic equipped satellite.

In fact there is another proof of this effect taking place literally every second of the day just above our heads. The precise clocks on the 31 global positioning satellites (GPS) circling the earth experience this effect. Time is moving faster up there with respect to time on earth because the satellites are further away from the massive body of the earth which is causing the time dilation effect at its surface.

The effect is very small, but it is enough to throw the clocks on each satellite off by about one-billionth of second everyday. This effect is enough to throw the positions measured on the earth’s surface off by 6 miles a day from the satellites’ perspective. Fortunately, there is a built-in correction program on each satellite to correct this time error.

Physicist know with this fact that the effect of time dilation near a massive object can be greatly amplified if we could fly a spacecraft near the most massive object in the universe, a black hole. This is Mother Nature’s time machine. In order for this to work everything must be done correctly. If this could be done the astronauts in the spacecraft must approach the black hole at the right speed and trajectory to avoid being drawn into it.

If done correctly, the astronauts in the spacecraft would circle the black hole for a while experiencing this slower passing of time while everyone else away from the black hole would experienced time moving at a twice the speed with respect to the astronauts in the spacecraft. If they stayed near the black hole for one year the people back on earth would see two years go by with respect to the astronauts in the ship. Obviously, this would not be a practical way to travel into the future because it will take too much time and energy to achieve any significant time travel into the future. However, there is a straightforward approach to traveling into the future and that is speed.

16,8 mile long particle accelerator at CERN
16,8 mile long particle accelerator at CERN
The underground tube at CERN
The underground tube at CERN
Another picture of the tube at CERN
Another picture of the tube at CERN

Speed And Time Connection

Another aspect from Einstein’s paper on Special Relativity states that time slows down to an observer approaching the speed of light. This is a fact proven by particle physicists at the CERN particle accelerator facility in Geneva, Switzerland. It is here where sub-atomic particles are accelerated to speeds near the speed of light in a tube buried underground in a circular tunnel 16.8 miles in length.

To study a very short-lived sub-atomic particle called a Pi-meson, which has a life span lasting only 25 billionth of a second, the particles are accelerated to 99.99% the speed of light. About a trillion of these particles are placed in the circular accelerator and are accelerated from 0 to 60,000 miles per hour in a few seconds with powerful magnets. The particles would continue to accelerate until they are traveling at 99.99% the speed of light. At this speed the particles are traveling around the 16.8-mile circular accelerator 10,000 times per second and the life span of the particles last 30 times longer due to the time dilation effect at speeds near the speed of light.

This same scenario can be done with a train traveling close to the speed of light on earth. This would be a very difficult task to do. But if we could, this is probably how it could be done. Imagine about 200 to 300 passengers board a train for a trip into the future. This is a one-way trip you cannot go back. I will explain why later.

The doors close and the train begins to accelerate slowly on a 25,000-mile track circling the earth. It continues to accelerate until it reach a speed close to the speed of light and once there it will be circling the earth seven times a second at that speed. To an observer outside the train if he is able to see inside the train, the passengers will appear to be moving very slowly due to the time dilation effect.

If this train continued at this speed going around and around and finally come to a stop after one week, one hundred years would have gone by for the people who are not on the train. The passengers on the train will only see one week go by. They will be 100 years into the future once they step off the train. The problem with this scenario is that it would require a lot of power, energy, advance technology and manpower to accomplish this but it would work if it could be done.

This scenario could be done in space as well with a very massive spaceship. The problem here is that it would require a lot of fuel and again manpower. Also the ship will have to literally travel out of the galaxy to achieve the same effect because it will take the ship almost four years just to reach 90% of the speed of light . By that time it would be just passing the nearest star, Alpha Centuari, about four light years from here. The other obvious problem is that this would be a one-way trip. You will not be coming back on this one.

Finally The Time Paradox

Cosmologists and physicists said there is one thing you cannot do in time travel. If you had a time machine you cannot go back in time to the past. This is what everybody wants to do with a time machine if they had one. But it is impossible and here is the reason why. You cannot have "effect" before "cause" or you cannot see the effect before cause. It doesn’t make sense. Here is an example, imagine if a scientist had assembled a gun to shoot himself in the past. Now let’s say he invented a time machine to open a portal about a minute back in time to shoot himself before he assemble that gun. He shoots his past self and his past self dies before he assembles the gun. Who fired the shot? It doesn’t make sense. It is a paradox. This is the way all events progress in the universe, cause then effect, not the other way around. Another way of looking at it is that the future is the “effect” and the present and past is the “cause”. Unfortunately, you will not be able to go back in time to witnessed the Wright brothers taking off at Kitty Hawk, North Carolina for their first flight.


1. Wikipedia

2. Information from Stephen Hawking's "Into The Universe" series on the Science Channel

An example of time paradox
An example of time paradox

© 2011 Melvin Porter

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Comments 51 comments

melpor profile image

melpor 14 months ago from New Jersey, USA Author

Glenn, thanks for reading my hub. Time slows down near massive objects. That is why time comes to a complete stop near a black hole because of its immense mass which affects the curvature of space near it. Stephen Hawkins also mentioned this effect in his tv series while explaining the possibility of time travel. The pyramids are very massive objects and their mass are affecting the curvature of space near them. That is why time slows down near them. The effect is extremely small but that is what is happening near massive objects. Time flows slower on earth compare to objects away from earth in space. However, the clocks on the GPS satellites run a little slower because they are moving at a speed close to 17, 000 mph. This tiny effect on the flow of time on the satellites cause the location of on points on the earth to be off by a few miles due to a calculation error. The error is corrected by introducing a correction factor for time dilation in the calculation to determine positions on earth.

Glenn Stok profile image

Glenn Stok 14 months ago from Long Island, NY

Generally interesting hub. But time dilation is caused by motion, not by mass. You correctly explain that near the end of your hub where you talked about the CERN particle accelerator in Geneva. But earlier in your hub you mentioned that time goes slower when near a large mass and you called that time dilation too. Can you give a reference to where you found proof of that? I'd like to read it to see if I missed something.

Abbi Clark profile image

Abbi Clark 17 months ago from Bangalore

Very excellent Hub. Time is matters a lot when it comes to perfect travel....

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travelours 18 months ago from Egypt

Great hub with value information thank you for sharing this hub in

Chaos Creator profile image

Chaos Creator 2 years ago from Providence

rulixa 3 years ago

time travel may be possible, but if not tied together with movement travel is has no sense

Look to

melpor profile image

melpor 3 years ago from New Jersey, USA Author

RonElFran, thanks for your comment. The "Cause and Effect" law is a well established law in the physics community. Every event in our natural world proceeds from a cause before you see the effect. For example, the process of nuclear fusion in the our Sun produces the heat and light we see from the Sun. The light from the Sun causes the water in the earth's ocean to evaporate into the air to produce clouds. The water vapors in the clouds eventually cool down to produce rain, etc. This is the way all events in the universe progresses in time and not the other way around. Again thanks for your comment.

RonElFran profile image

RonElFran 3 years ago from Mechanicsburg, PA

Great hub. I do wonder if your conclusion that cause and effect preclude travel back in time is airtight. I seem to dimly remember that some discoveries in sub-atomic physics bring the principle that effect cannot precede cause into question. Would it be on more sure footing based on conservation of matter and energy, which would seem to forbid removing matter from one time and injecting it into another. Anyway, I enjoyed reading.

melpor profile image

melpor 4 years ago from New Jersey, USA Author

Diliptech, thanks for your comment.

diliptech profile image

diliptech 4 years ago from INDIA

Of course Time travelling in past for matter states is never possible and you could't just meet your ancestors, but i think we should't loose our hope in not geeting any feel of that.

melpor profile image

melpor 5 years ago from New Jersey, USA Author

Dipless, thanks for your comment and for stopping by to read my hub.

dipless profile image

dipless 5 years ago from Manchester

An interesting hub, nicely written.

melpor profile image

melpor 5 years ago from New Jersey, USA Author

TheWorldNow, thanks for your comment and for stopping by. I hope you enjoy reading my other hubs.

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TheWorldNow 5 years ago from Washington DC

Wow, I'm definitely following you. I look forward to reading all your other hubs!

melpor profile image

melpor 5 years ago from New Jersey, USA Author

crystolite, thanks for the comment and for stopping by to read my hub.

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crystolite 5 years ago from Houston TX

Interesting hub,thanks for sharing.

melpor profile image

melpor 5 years ago from New Jersey, USA Author

Thanks Montecristo. Thanks for stopping by to read my hub.

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montecristo 5 years ago from Hampton Roads, Virginia

Great hub. I enjoyed it.

melpor profile image

melpor 5 years ago from New Jersey, USA Author

Chinemeremz, thanks for your comment. Time travel is possible, the problem is that it requires a lot of energy to make it happen. Massive amount of energy is needed to push something much larger than the sub-atomic particles in an accelerator to near the speed of light. Currently scientists are able to push short-lived sub-atomic particles near the speed of light to make it possible to observe them since time slow down near the speed of light thus slowing the decay process of sub-atomic particles down. Also time does slow down near massive objects such as the pyramid of Giza.The effect is so small. This is proven by the fact that time moves faster when objects are further away from earth as proven from the GPS satellites circling the earth.

chinemeremz profile image

chinemeremz 5 years ago

Time travelling as seen from the physicist point of view cannot be feasible due to some irreconcilable facts like mass, error and human inconsistencies.

Time is unfortunately irreversible-that even the optical illusion at the pyramid Giza is over-hyped.

Oh I wish this was true (time travelling), as I wish to go back in time and reverse all the silly mistakes I made in the past.

However, the only way we can time travel is making the best of the moment we currently exist.

Thanks for this wonderful academic discourse, really pro scholarship.

Got my vote up!

sligobay profile image

sligobay 5 years ago from east of the equator

Yesterday is only a dream and tomorrow is only a vision, but today well -lived, is the goal.

melpor profile image

melpor 5 years ago from New Jersey, USA Author

Sligobay, thanks for your comment. As you can see the time paradox pretty much says we cannot change what already happened because the effects of the event continues forward in time.

sligobay profile image

sligobay 5 years ago from east of the equator

melpor, greetings from the future, past and present. Time is of the essence and I learned something new about cause and effect. I am now following. Thank you.

melpor profile image

melpor 5 years ago from New Jersey, USA Author

Time4Travel, thanks for your comment. I also enjoy this topic and generally tried to watch most movies on this subject. It is a fascinating subject.

Time4Travel profile image

Time4Travel 5 years ago from Canada

A neat hub that is well written. I must say-- I do love this topic!

melpor profile image

melpor 5 years ago from New Jersey, USA Author

Henry, All the pictures are in photo capsules and each photo were obtained through google search in the image tab of google.

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henry1robertson 5 years ago from Los Angeles, CA 90013

This page attractive for other users. How are you decorate it?

melpor profile image

melpor 5 years ago from New Jersey, USA Author

2besure, thanks for stopping by and thanks for the comment. Time travel would be fun if we could done it.

2besure profile image

2besure 5 years ago from Charlotte, North Carolina

Great hub on time travel. Well done! If it were possible, I would be one of the first to sign up to go back and forward in time. Voted up!

melpor profile image

melpor 5 years ago from New Jersey, USA Author

Genna East, thanks for your comment. I agree with you. If I had a choice I would choose to go back in time but all you will be able to do is observe the events. You will not be able to change anything due to the time paradox problem.

Genna East profile image

Genna East 5 years ago from Massachusetts, USA

Fascinating hub...especially, the Time Paradox. Should we be given a choice to embark on a little time travel, I'm fairly certain that most people would choose to go back in time. A vote up and thank you1

melpor profile image

melpor 5 years ago from New Jersey, USA Author

Agvulpes, I read an article where scientists have successfully teleported a small quantity of matter from one point to another using a beam of light to make it occur. But I believe it will be a while if it is ever possible to teleport something as complex as a living organism from one point to another. Thanks for reading my hub.

agvulpes profile image

agvulpes 5 years ago from Australia

melpor your explanations for time travel are very plausible and I very much enjoyed reading your Hub. I am wondering what your thoughts are on 'matter' transportation such as the 'Beam me up Scottie' machine ?

Rated up and bookmarked!

melpor profile image

melpor 5 years ago from New Jersey, USA Author

Joyus, thanks for your comment. That is a good point. I forgot about adding multiverse into the picture but like you say travel between universes is highly impossible right now.

Joyus Crynoid profile image

Joyus Crynoid 5 years ago from Eden

Great hub melpor. I would say that the the irreversibility of time is explained by the second law of thermodynamics.

In his book "The Fabric of Reality" quantum physicist David Deutsch speculates that time travel into the 'past' might be possible in a multiverse, if it were possible to 'sidestep' from one universe to another: in which case the paradox you described is resolved by the fact that cause and effect actually occur in different (parallel) universes. Of course, not everyone accepts the many-universes interpretation of quantum mechanics; and even if it is correct, it is difficult to envision how one might travel between alternate universes!

melpor profile image

melpor 5 years ago from New Jersey, USA Author

A M Werner, thanks for your comment. The possibility of time travel is here but we just don't have the technology, resources, and manpower to make it happen on a larger scale.

A M Werner profile image

A M Werner 5 years ago from West Allis

Great hub - much to think about - much to ponder. Glad my life is moving just fast enough to do that. Any faster and I'd get dizzy. Peace

melpor profile image

melpor 5 years ago from New Jersey, USA Author

Docmo, Thanks for your comment. I also find time travel to be a fascinating subject for many years. I always enjoyed various ways it was presented in movies and TV shows and my favorite movie on this subject is the classic one "The Time Machine".

Docmo profile image

Docmo 5 years ago from UK

Brilliant ! Something that fascinated me for a long-time. the very first story I wrote when I was at school involved the grandfather paradox. I have since red a lot of sci-fi and theory around these concepts. I find this hub a very effective summation.voted up!

melpor profile image

melpor 5 years ago from New Jersey, USA Author

Jeffrey, thanks for your comment. Time tunnel was one of my favorite sci-fi show back in the day. I enjoyed watching it because it educated me on some very historical events.

Jeffrey Talbot 5 years ago

It is nice to see that THE TIME TUNNEL (ABC 1966-67) tv series is still remembered!

And it is an exciting prospect that time travel may one day be a scientific reality-achievement.

Let's hope that it happens in our lifetime.

melpor profile image

melpor 5 years ago from New Jersey, USA Author

Ssaul, thanks for your comment. Yes it would be nice if you could flip a switch and go back in time to correct mistakes that you made. But remember going back in time may not be possible since you violates the "Cause" and "Effect" principle. It would be a paradox if you could do that.

melpor profile image

melpor 5 years ago from New Jersey, USA Author

Dahoglund, once again thanks for the your comment. Movies involving time travel were always my favorite in the Sci-Fi genre. After watching them they always left me thinking and wondering.

ssaul 5 years ago

hey how about we make a time machine, with technology enhancing everyday, its possible, lol! then when you want to correct something we just flip the switch. I would really like to change something really bad only knows.

dahoglund profile image

dahoglund 5 years ago from Wisconsin Rapids

Time stories have been my favorite form of Science fiction, although I don't much care for most of movie and TV treatment of it.

melpor profile image

melpor 5 years ago from New Jersey, USA Author

TahoeDoc, I hope the above comment clears up the confusion about black holes. They are not that small. They are small relative to the size of everything else in the universe. Thanks for your comment.

melpor profile image

melpor 5 years ago from New Jersey, USA Author

Gordon, black holes are large based on what Stephen Hawking said in his "Into the Universe" series. If I remembered correctly they are dense but they are millions of miles in diameter and that is small compared to most things in the universe. They are large enough for stars and other objects in space to fall in. That is what is happening at the center of our galaxy and there is proof of this. Thanks for bringing that point up and thanks for your comment.

TahoeDoc profile image

TahoeDoc 5 years ago from Lake Tahoe, California

Melpor - excellent hub! You have a gift for explaining complicated matters very well.

But now I'm confused by the above post...why can't something be both dense and large? I don't see how that's a contradiction. In any case, I understood it as a theoretical explanation in the hub.

Gordon Hamilton profile image

Gordon Hamilton 5 years ago from Wishaw, Lanarkshire, United Kingdom

I think that your Hub is absolutely wonderful and extremely informative in a great many ways - so why make it scientifically inaccurate??? "Large," black hole? How can the most dense matter theoretically possible be deemed to be, "Large...???" in what is effectively human comparitive terms? I respectfully refer you, Sir, to the works of Professor Stephen Hawking and the theory that, "Black holes," are configurations of collapsed matter so dense that light itself can not reflect from their substance...

Please be assured that I am genuinely interested and not being critical for its own sake.

Yours sincerely and genuinely,


melpor profile image

melpor 5 years ago from New Jersey, USA Author

Suziecat7, thanks for comment. But remember you can not go back to the past. You are the effect and the past is the cause. Cause comes before the effect.

suziecat7 profile image

suziecat7 5 years ago from Asheville, NC

Very interesting Hub. If it was possible to time travel, I'd travel back to the 19th century. Great Hub.

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