# Time travel possible? **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [January 6, 2000, 8:08am UTC](https://boards.straightdope.com/t/time-travel-possible/745 "2000-01-06T08:08:00Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [January 14, 2000, 4:03am UTC](https://boards.straightdope.com/t/time-travel-possible/745/21 "2000-01-14T04:03:00Z")
Areynaldo. I can agree with everything you said. Especiall where you say > [@](#): > > It took a change in the idea to have humans flying, i.e. now we use airplanes that use fluid physics to fly, we don’t go around flapping our legs and arms. The fact that you mention _fluid_ in reference to flight is awesome. Few folks know that air is a fluid. Don’t they watch Bill Nye? 😃 ---
**Author:** ![areynaldos](https://avatars.discourse-cdn.com/v4/letter/a/4bbf92/32.png) [@areynaldos](https://boards.straightdope.com/u/areynaldos)\ **Post date:** [January 14, 2000, 4:51pm UTC](https://boards.straightdope.com/t/time-travel-possible/745/22 "2000-01-14T16:51:00Z")
SmickD: thanks for your support 🙂 ! The fact is that some people tend to get confused with what science and its laws and theories mean. Science is a self-correcting tool. But still, there are things that are quite understood and firmly established. Maybe a new and better theory can arrive, but that doesn’t mean that prior observations were plainly wrong. Relativity goes far beyond Newtonian laws, but this doesn’t mean that we cannot use Newton physics to model an apple falling from a tree, or establishing for sure that the apple will ALWAYS fall and will NEVER go up. This is the difference between well known facts (and proven ones) and the technological impossibilities. Another common example of these is the sound barrier, which a lot of people tend to quote when one talks about the impossibility of going fastest than light. But crossing the sound barrier rose some technical issues, though it is perfectly possible. I don’t know who is really to blame (I have some ideas, though) about this whole anti-science movement, particularly in the US… The scientific illiteracy is very high, and that is something to get really concerned. Anyway, time travel is worth exploring from a scientific point of view. ---
**Author:** ![Hyxtryx](https://avatars.discourse-cdn.com/v4/letter/h/7feea3/32.png) [@Hyxtryx](https://boards.straightdope.com/u/Hyxtryx)\ **Post date:** [January 18, 2000, 9:54pm UTC](https://boards.straightdope.com/t/time-travel-possible/745/23 "2000-01-18T21:54:00Z")
SMAK D wrote: \>\>\> Time does not flow. We percieve it to do so but it does not. This is made evident by the idea that time changes the faster one goes. If this is so, it clearly indicates that time is not fluid in nature, but more elastic, and cannot be traveled through. \<\<\< Nonsense. If time changes as we approach the speed of light, then time is fluid! If you agree that the speed of time changes, then it it should be a no-brainer that time travel might be possible. In fact, we’re travelling through it right now! Time is interlinked with space. If you say time does not flow then you must also not believe in space and all matter within it. \>\>\> Light is made of particles called photons, and is not comprised of waves. \<\<\< Where are you getting this info? It is a well known fact that light behaves as both a particle and a wave. I suggest looking up the “double slit experiment” somewhere. \>\>\> other things are not comprised of particles, like radio waves, and still travel at the speed of light. \<\<\< Wrong, and wrong. Radio waves are the exact same thing as light, only they are of a different frequency. Both are electromagnetic waves. Also, radio waves do not travel at the speed of light, they travel slower. I am surprised nobody has called SMAK D on this gross error. How can you even mention the word “relativity” and not know these things??? ---
**Author:** ![Hyxtryx](https://avatars.discourse-cdn.com/v4/letter/h/7feea3/32.png) [@Hyxtryx](https://boards.straightdope.com/u/Hyxtryx)\ **Post date:** [January 19, 2000, 1:46am UTC](https://boards.straightdope.com/t/time-travel-possible/745/24 "2000-01-19T01:46:00Z")
Hmm, I may be wrong about radio waves travelling slower than light. A quick web search shows that it is generally thought of to be the same. But this site seems to hint it isn’t. At least not in an “interstellar medium”. [http://searchpdf.adobe.com/proxies/0/24/52/19.html](http://searchpdf.adobe.com/proxies/0/24/52/19.html) “”" Light and radio waves are definately the same thing however, just different frequencies. Here’s the quote from the web page I noted: “By measuring the times of arrival of pulses from the same pulsar at different frequencies you can determine the distance to the pulsar, as long as you know the speed of radio waves through the interstellar medium at different frequencies.” ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [January 19, 2000, 2:02am UTC](https://boards.straightdope.com/t/time-travel-possible/745/25 "2000-01-19T02:02:00Z")
time travel is not only possible for biological life, but has been proven… In one of NASA’s experiments, they sent 1 of 2 calibrated (and I assume very accurate) clocks up w/ the shuttle and when it came down there was a definite discrepency, a few seconds, but the shuttle and its passangers have traveled ‘through’ time faster then the avegare joe. * * * ---
**Author:** ![JoeyBlades](https://avatars.discourse-cdn.com/v4/letter/j/a87d85/32.png) [@JoeyBlades](https://boards.straightdope.com/u/JoeyBlades)\ **Post date:** [January 19, 2000, 2:04pm UTC](https://boards.straightdope.com/t/time-travel-possible/745/26 "2000-01-19T14:04:00Z")
> [@](#): > > In one of NASA’s experiments, they sent 1 of 2 calibrated (and I assume very accurate) clocks up w/ the shuttle and when it came down there was a definite discrepency, a few seconds, but the shuttle and its passangers have traveled ‘through’ time faster then the avegare joe. Actually, it was only a few billionths of a second difference and actually, the shuttle passengers suffer from time dialation, meaning, for them, they were travelling through time slower than their cohorts at mission control (albeit only fractions of a second slower). This is one of the experiments that is often used to show the validity of Einstein-Lorentz time dialation (a part of Einstein’s theories of relativity). It in no way demonstrates that time travel into the past is possible via faster than light travel. ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [January 19, 2000, 4:35pm UTC](https://boards.straightdope.com/t/time-travel-possible/745/27 "2000-01-19T16:35:00Z")
from Hyxtryx: > [@](#): > > Hmm, I may be wrong about radio waves travelling slower than light. A quick web search shows that it is generally thought of to be the same. But this site seems to hint it isn’t. At least not in an “interstellar medium”. Here is the relevant text from the document you listed. > [@](#): > > One powerful method is to use the phenomenon of dispersion. All forms of electromagnetic radiation, including radio waves, travel at the same speed in a vacuum. This speed is speed of light > c = 3 x 10^8 = meters/sec. > However, interstellar space is not quite a vacuum. On the average the interstellar medium consists of a few atoms and a > few free electrons in each cubic centimeter. > > It isn’t much, but it’s enough to slow down electromagnetic waves slightly. The lower the frequency, the slower the radiation travels. This means that, though the effect is small, pulses from a pulsar arrive a fraction of a second earlier at higher frequencies than at lower frequencies, because the higher frequency pulses travel faster through the interstellar medium. ---
**Author:** ![frolix8](https://avatars.discourse-cdn.com/v4/letter/f/f04885/32.png) [@frolix8](https://boards.straightdope.com/u/frolix8)\ **Post date:** [January 20, 2000, 6:57am UTC](https://boards.straightdope.com/t/time-travel-possible/745/28 "2000-01-20T06:57:00Z")
I would submit that there are 2 methods of "time travel, at least in the popular usage of that term, that are not prohibited by any laws of physics. The first is travel into the future, which is what living is all about. A more interesting version is portrayed in Woody Allen’s “sleeper”, where suspended animation is used. Not feasible now, true, but it doesn’t violate any laws of physics either. The second is witnessing the past. If we look at our image in a mirror we are witnessing the past, light has to travel the distance to the mirror and back again before we see it, so we are really seeing an image from the past. This has very important ramifications for astonomers and cosmologists, since we can currently see events which transpired a very long time ago. It would not violate any laws I know of to theorize that a reflecting surface could exist in space somewhere which could reflect an image of the earth back to us. In that case we could observe the earth as it was long ago. Other than that, I think all other forms of time travel require a major rewrite of the universe. First post, how did I do? ---
**Author:** ![JoeyBlades](https://avatars.discourse-cdn.com/v4/letter/j/a87d85/32.png) [@JoeyBlades](https://boards.straightdope.com/u/JoeyBlades)\ **Post date:** [January 19, 2000, 7:24pm UTC](https://boards.straightdope.com/t/time-travel-possible/745/29 "2000-01-19T19:24:00Z")
> [@](#): > > First post, how did I do? On the mark, I’d say. Welcome. ---
**Author:** ![brooklyn44](https://avatars.discourse-cdn.com/v4/letter/b/51bf81/32.png) [@brooklyn44](https://boards.straightdope.com/u/brooklyn44)\ **Post date:** [January 20, 2000, 12:19am UTC](https://boards.straightdope.com/t/time-travel-possible/745/30 "2000-01-20T00:19:00Z")
frolix8 bravo! ---
**Author:** ![Bricker](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@Bricker](https://boards.straightdope.com/u/Bricker)\ **Post date:** [February 8, 2000, 3:23pm UTC](https://boards.straightdope.com/t/time-travel-possible/745/31 "2000-02-08T15:23:00Z")
> [@](#): > > Originally posted by oldbellboy: > **Until then, we have to content ourselves with the SF time travel stories, the best of which, in my humble opinion, are Jack Finney’s “Time and Again”, and its sequel, “Now and Again”. (fuggeddabout that silly movie version of Time and Again with Christopher Reeve and Jane Seymore. Bet you didnt know that Jack Finney had a small role in that flick)** Well, in the category of, “No one will care, and it’s off topic, but I must correct this tiny point…” 🙂 The sequel to Time and Again, by Jack Finney, is From Time to Time, of course also by Jack Finney. Scribner, February 1996, ISBN: 0684818442. - Rick ---
**Author:** ![jab1](https://avatars.discourse-cdn.com/v4/letter/j/ee7513/32.png) [@jab1](https://boards.straightdope.com/u/jab1)\ **Post date:** [February 8, 2000, 11:36pm UTC](https://boards.straightdope.com/t/time-travel-possible/745/32 "2000-02-08T23:36:00Z")
I say time travel is possible because they said so on an episode of _The X-Files_. It involved tachyons and cryogenics, so the traveller would be able to survive the trip. Mulder said it. I believe it. That settles it. * * * \>\< DARWIN \> \_\_ **L\_\_\_L** ---
**Author:** ![Michael\_Masterson](https://avatars.discourse-cdn.com/v4/letter/m/53a042/32.png) [@Michael\_Masterson](https://boards.straightdope.com/u/Michael_Masterson)\ **Post date:** [February 21, 2000, 6:23am UTC](https://boards.straightdope.com/t/time-travel-possible/745/33 "2000-02-21T06:23:00Z")
Time travel IS possible, but only for certain particles, and only into the future. Trust me! * * * ~-MCM-~ ---
**Author:** ![JoeyBlades](https://avatars.discourse-cdn.com/v4/letter/j/a87d85/32.png) [@JoeyBlades](https://boards.straightdope.com/u/JoeyBlades)\ **Post date:** [February 21, 2000, 1:45pm UTC](https://boards.straightdope.com/t/time-travel-possible/745/34 "2000-02-21T13:45:00Z")
So-o-o-o… which kinds of particles _don’t_ travel into the future? Enquiring minds want to know… ---
**Author:** ![areynaldos](https://avatars.discourse-cdn.com/v4/letter/a/4bbf92/32.png) [@areynaldos](https://boards.straightdope.com/u/areynaldos)\ **Post date:** [February 27, 2000, 12:09am UTC](https://boards.straightdope.com/t/time-travel-possible/745/35 "2000-02-27T00:09:00Z")
\ In one of NASA’s experiments, they sent 1 of 2 calibrated (and I assume very accurate) clocks up w/ the shuttle and when it came down there was a definite discrepency, a few seconds, but the shuttle and its passangers have traveled ‘through’ time faster then the avegare joe. \ I believe the thread has changed a bit. You are confusing time travel in the popular understood way and time in a relativistic sense. The fact that time is different to different observers depending on their relative speed is not the same idea of time travel in the way that you can go to a different point in time. The clocks experiment, the astronauts in the shuttle and many other experiments are only confirmations of the Einstein’s theories. The same theories that forbid the time travel in the other sense. i.e. the clocks are not traveling backward or forward in time, they just have a different sense of time. In this sense, we are _all_ travelling in time. ---
**Author:** ![Wes](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@Wes](https://boards.straightdope.com/u/Wes)\ **Post date:** [February 27, 2000, 3:14am UTC](https://boards.straightdope.com/t/time-travel-possible/745/36 "2000-02-27T03:14:00Z")
I travel through time every day. At the rate of one hour per hour, in the “forward” direction. Forward, of course, being defined where effect occurs after cause. 😛 Why is everybody so hyped up about it? ---
**Author:** ![Michael0916](https://avatars.discourse-cdn.com/v4/letter/m/aeb1de/32.png) [@Michael0916](https://boards.straightdope.com/u/Michael0916)\ **Post date:** [February 27, 2000, 4:53am UTC](https://boards.straightdope.com/t/time-travel-possible/745/37 "2000-02-27T04:53:00Z")
Okay time travel is possible. That’s all there is to it. I know how it is done…well actually I do in fact have a theory I would some day like to try but it’s such a simple concept I say to myself that if it really worked we’d be doing it. Okay here we go. Let’s say it takes you 6 hours to travel through 2 time zones. I live in Florida so let’s say I was going to Montana…I think that’s in the Rocky Mountain Time Zone. If my plane leaves at 12:00 a.m. I would get there at 4:00 a.m. rather than 6:00. Now let’s say that I was not going to Montana and instead went the other way. I would be at 8:00 a.m. The amount of time doubles. The quicker you can make it through time zones the more time you shave off your journey. Now let’s say we wanted to go all the way around the world. If we could somehow do this faster than a day we could actually go back in time or forward in time depending on if we go east or west. So if someone would just invent a transportational device that would allow us to go that fast…we’d be fine. : ) ---
**Author:** ![pennys](https://avatars.discourse-cdn.com/v4/letter/p/958977/32.png) [@pennys](https://boards.straightdope.com/u/pennys)\ **Post date:** [February 27, 2000, 5:12am UTC](https://boards.straightdope.com/t/time-travel-possible/745/38 "2000-02-27T05:12:00Z")
I think the most recent theories of time travel involve sending one end of a wormhole (sorry I can’t explain exactly what a wormhole is but it’s not the pink slimey one) off at the speed of light so that it undergoes the usual time dilation effect, and then bringing it back so that the two ends are together, in which case you have a tunnel which goes from the present to the past. If you can hold it stable, that is. ---
**Author:** ![Michael0916](https://avatars.discourse-cdn.com/v4/letter/m/aeb1de/32.png) [@Michael0916](https://boards.straightdope.com/u/Michael0916)\ **Post date:** [February 29, 2000, 2:57am UTC](https://boards.straightdope.com/t/time-travel-possible/745/39 "2000-02-29T02:57:00Z")
Pennys thank you for ruining all chances at allowing me to sleep tonight…now there’s something to think about. Hmm…STOP IT! Now I’m so confused. If someone can interpret that last post into layman’s terms so that I can understand it I’d appreciate it…but for now I’ll just keep trying to understand. * * * –Michael Or would you rather talk about monkeys? ---
**Author:** ![Saltire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saltire/32/553_2.png) [@Saltire](https://boards.straightdope.com/u/Saltire)\ **Post date:** [February 29, 2000, 11:52pm UTC](https://boards.straightdope.com/t/time-travel-possible/745/40 "2000-02-29T23:52:00Z")
> [@](#): > > Pennys thank you for ruining all chances at allowing me to sleep tonight…now there’s something to think about. Hmm…STOP IT! Now I’m so confused. If someone can interpret that last post into layman’s terms so that I can understand it I’d appreciate it…but for now I’ll just keep trying to understand. I’ll try, but I have to assume a layman that believes in General Relativity and can understand it’s basics (which is what I am, myself). From Einstein, we know that space is curved. He also tells us that travelling near the speed of light slows the passage of time. This was all stated by 1915, though it wasn’t proven by experiment and observation until later. What has come up more recently is a group of physicists that play around with the kind of shapes space can assume when it curves. The science is called spacial topology, and it’s almost more of a branch of mathematics than of physics. Their leader is a very sharp cookie named Kip Thorne. These guys have shown that it is possible for a wormhole to exist. A wormhole is basically a shortcut through space (and sometimes through time). Imagine that normal space is on one side of a sheet of clay. Put two dots a meter apart. In normal, nearly flat space, the shortest distance between them is a meter. A wormhole would be like folding the sheet so the two dots are superimposed and poking a hole in the clay. Now there is a path, outside normal space, that allows you to traverse from one point to the other by traveling less than a centimeter. That’s a wormhole. Let me add here that the spacial topologist don’t try to explain how to form a wormhole. They don’t know how you’d make one, and neither does anyone else. They are just looking at the consequences of the theory. The theory does predict natural wormholes in the quantum realm that would create shortcuts on the order of the diameter of a proton, but even they don’t last long enough to be observed by present methods. Now the trick. After you’ve got your wormhole (God only knows how), you accelerate one end only. This creates a time differential between the ends that is larger (possibly much larger) than the normal time to go through it. In this acceleration process, you make sure the ends are near one another when they stop. Now, by steping through one end of the wormhole, you pass into the future. Going the other way takes you into the past. Of course, you can only go back as far as the time when the wormhole was formed, but it would work. The last amazing thing here, is that the spacial topologists say these wormholes do not need large gravitational fields to exist. So you wouldn’t be torn to quarks getting near one. I hope that helped. I realize a lot of it restated what Cecil said, but I tried to take a different angle on it. By the way, I don’t have any references here with me, so I couldn’t add details like the university where Kip Thorne works. Most American spacial topologists were graduate students under him in their student days. Another little anecdote here is that the whole thing about wormholes as actual theoretical entities (was that an oxymoron?) came about through science fiction. When Carl Sagan was writing his book ‘Contact’, he asked Kip Thorne if the wormholes he’d used in the story could exist (given sufficient technology). Thorne gave the problem to his grad students, and they all invented a branch of physics. * * * It’s from heraldry. The proper heraldic term for things like the “Cross of St. Patrick.” Look it up. [Previous page](https://boards.straightdope.com/t/time-travel-possible/745.md?page=1) [Next page](https://boards.straightdope.com/t/time-travel-possible/745.md?page=3)