# Question regarding the paradox of time travel

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I have just started really getting into time travel. What I have read so far regarding it is very interesting, though very daunting in its explanations. What I am wondering is about moving between the past and future and the speed at which must be obtained to do so. First off, the granny paradox. Regarding how if you travel in the past and kill your grandmother that you would not be born and therefore not traveling back in time to actually kill her. Would it not stand to reason that you could not actually travel back in time to a point where time travel didnt exist as you would not (at the past time) have the means to travel in time? Thereby making it impossible for you to go to that time? Would it not be more likely that a person could travel to the future, and then go back (if traveling in the past is possible) to a point in time right on or after the invention of time travel?

Secondly. I understand that as you approach the speed of light time starts to slow down. Many of the hypothesis that I have read regarding time travel include going faster than the speed of light or using a worm hole, or black hole with a opposite white hole. Why is it that traveling infinitely slow would not do the same thing? As you begin to slow down time for you remains constant and does not change but time outside of you speeds up. Instead of trying to break the speed of light, can we not slow ourselves down to the point that everything else travels at the speed of light around us??

Any help would be greatly appreciated!!

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okay the first question:

the second question:

look up the twin paradox theory, as you get closer to the speed of light your mass will pick up energy and will make you age less that is why the twins age at different times.

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I dont question that you would age less as you draw closer to the speed of light. What I question and even the twin paradox that you suggested to look up confirms my idea, is that even at 86% the speed of light in the example provided by Wiki, the person going on the trip would age only 5.14 yrs to the Earth based person coming in at 10.28 yrs. Now by that measure a person would have to continually be at or close to the speed of light, traveling for years to make time travel worth doing in the first place. My idea is to slow down to the point where time almost stops while everyone continues on at a regular speed which to the person slowing down would seem very very fast. Since the theory of special relativity states that nothing can exceed the speed of light, what I suggest is bending that law and not traveling faster than light but traveling slower than everything else around us.

One other thought, regarding black holes. I have heard that there may be an infinite number of black holes everywhere. Following the logic that says only something supermassive collapsing on itself as a star would can create the gravitational forces needed to create a black hole, if a black hol opens up in empty space with no mass of decent size to consume, I wonder if a black hole doesnt consume time as it does matter and energy? What if a black hole consumes time (which would be the past) and the enough matter that when as Stephen Hawking stated "die out" creates another universe with existing matter and time. Since matter cannot be created or destroyed but only changed.

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One other thing to concider is you are thinking from the boundries of the universe you live in.

Out side the universe you may not need to travel at the speed of light just find a door way out of it then u may be able to travel to any point with in it.

One other thing you need to think about is size, to us the universe is so big we think we neeed to travel at the speed of light, but out side of it you may not need to travel at such speeds.

The univere may just be a a super computer server sittin on a desk top that allows all of the elements to be with in it.

On the desk top we may be millions of years old but out side of the universe there may be no time at all.

My info is not fact just thought.

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So very true and thats why I suggested the possibility of black holes consuming time, space, and matter and creating other universes outside our own. Whether they be larger than ours or smaller. I had also wonder about using a variant on the super collider technology to possibly exceed the speed of light barrier in space. My thinking is that while a vacuum can be created on Earth in a super collider, imagine a probes speed if the collider was in space with a barrel of sorts that could be directed. As the magnets bring the probes speed upto close to the speed of light and then forced through the barell the probes speed could be increased even faster with its own thrusters. Not sure how the whole thing would work in reality but, it could be a way to increase speeds that are now impossible to achieve with thrusters and sling shots from a planets gravity.

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Maybe we are notes on a computer record player someone has the power to play any tune they like and some of us just make it sound good or bad.

I guess all you can do is figure out a way to play your own music and create your own sounds based on info u have.

Maybe we are a group of sounds on a computer server i wonder if we sound good or bad to who is listening.

Is the music random or is it set you mite ask yourself.

And the big question is can you change the music and can you go back to the start and play the same tune or a new one. Or take the best from one song and add them to the new one you make.

Best Regards,

Blair.

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well your guys have a good understanding of time, im trying to prove that time acts like water and your black hole theory would be just as simple as a whirlpool of time that spins all energy from a low energy into a high energy state. as for time travel, it would be as simple as making a bubble of time and manoeuvering it forward and backward into time. the hyper conchy surface needed to collapse time would make the walls of the bubble and some sort of pump would be needed to move it back and forth.

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I watched a program on the Discovery Channel called Hawkings Paradox. His theory stated that after a period of time all matter in a black hole would be annihalated and the black hole itself die out. Now lets assume that he is wrong and that all the matter, and time are not annihalated. Lets also assume that this particular black hole is not rotating and therfore theoretically does not have an opening and or white worm hole attached to it. Since matter cannot be created or destroyed but only changed, and since all matter has density to one degree or another, what happens to all the matter and time within a black hole? Could a black hole in and of itself be a "container" of sorts for other universes within our own universe? There have been reports of scientists finding evidence of matter being ejected at very high velocities out of what they believe is a black hole? Could the possiblity that the universe is expanding be the result of us being contained inside a black hole and some other black holes feeding matter and time into our universe? If that could be the case then that could mean that just by going into a black hole could send you to a different universe and or time.

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Or maybe blackholes are just a universe recycling system, tuning space matter into re use able matter again.

A self contained bubble that never ends.

A Set and forget system, you can enter and leave at any point.

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i think its possible for both ideas to exist, i think you can have a black hole connecting two dimensions and the space-time between them can act as a drain that pulls every thing from one dimension to the other. universe recycling system that you talk about can be just time,space-time, spinning into existence and pulling from other matter and energy that can not be created just destroyed.

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>i think its possible for both ideas to exist, i think you can have a black hole connecting two dimensions and the space-time between them can act as a drain that pulls every thing from one dimension to the other. universe recycling system that you talk about can be just time,space-time, spinning into existence and pulling from other matter and energy that can not be created just destroyed.<

The problem with this is two-fold. First, we have Hawking Radiation, which means black holes leak, which means "we know where the stuff that falls into a black hole eventually goes". And secondly, if white holes exist, they'd be hard to miss- there would be countless billions of them throughout the universe, and we have not seen one yet.

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Grandfather Paradox (I know you said Granny, but I'll go with Grandfather for the moment, sorry, habit) can be easily explained away (at least by my understanding). The Grandfather you kill isn't technically 'your' (timeline self) Grandfather. By technical definition, you're going back in 'time' and eliminating a man from a different reality to yours. I may not be entirely clear. Allow me to try and explain.

You live on timeline A -------

Grandfather on timeline B --------

You go back in time (by doing so entering B), meet and kill your Grandfather in B, then you go forward in time (returning back to A). What you've done hasn't impacted your timeline (proof being, you're still alive/you completed the task). Very smartly, time travel only appears to affect anything AFTER when it occurs (in timeline B, time travel had occured before the potiential Grandfather's death caused by time travel).

Really, all you're doing is making (well, technically, it's already been made and you're just another peice of it's puzzle) an alternate reality.

I'm sure you're thinking 'Why not just go to my Timeline A Grandfather'. Well, by technical definition, your discovery of time travel is an alternate reality in itself. There's another version who didn't discover it. Another version who did, but used it to save a person. Another version where you discovered it, and got killed as it backfired. You can't reach Timeline A simply because you create a new Timeline when you try (as your Timeline A has no previous events of Time-Travel)... B. Or C, Or D etc etc etc.

Second point. Truth is, these are largely theories. For anyone who hasn't worked it out, a white-hole is actually... a Star. A wormhole would probably required vast amounts of energy to work (take into account it is supposed to make a long distance short) and would have probably been very obvious on scopes. I am not entirely sure of the reasoning behind faster than light, but it does have sigificant drawbacks, Force (crushed astronaut anyone?), energy and costs/technology. One thing I will note however (pay heed those of you interested in faster than light travel) it can be done...

Black holes are strong enough to overwhelm light's fanastic speeds and pull it in. This would imply the gravity's pull has greater strength than the speed of light and could theorically make an object move faster than the speed of light to it's central core. If light went directly into the black hole, and combined with the extra gravimetric shear of the blackhole, the light would increase in speed - going, you guessed it, faster than the speed of light.

In regards to your counter-theory of the speed of light - unfortuantly not. If our lives went past in a blink of an eye, we would not technically be time-travelling, we would be in statis or dead.

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Subject: Re: Question regarding the paradox of time travel

Neo,

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Instead of trying to break the speed of light, can we not slow ourselves down to the point that everything else travels at the speed of light around us??

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"Slowing yourself down", remember, is a relative effect. In relativistic physics your linear velocity is something that you measure against some other object. You can slow down to a stop relative to the object against which you're measuring your speed. That's the rest frame. But that's as slow as you can go relative to that frame. Any slower and you're just accelerating in the opposite direction.

To see everything zipping, not around you, but directly toward you at the speed of light you need to accelerate to the speed of light. The problem here is contained in the first sentence. Everything in the universe, if you travel at the speed of light, is traveling directly at you. And I mean everything. You are on a collision course with every object in the universe simultaneously because you are then a "lightlike" object. At the speed of light all points in the universe are instantly accessible simultaneously. At the speed of light you will instantly hit an infinitely dense point directly ahead of you that contains all the mass of the universe.

The speed of light, for objects that has intrinsic rest mass, like people and space ships, is The Mother of All Dead Ends.

Fortunately we don't have to worry about this because objects that have intrinsic rest mass can't be accelerated to the speed of light. The speed of light isn't a barrier, it is a boundry. It is the space-time boundry that divides space from time.

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Darby,

Are there any other equations that have the "rate of change of time" as a variable? The time dilation equation is the only one I know about.

So I think it says if you can get to a velocity of 2c^2 (impossible, I know) the rate of change of time goes in reverse at the same rate time was passing when the object was at rest.

Hey, come to think of it, why do they use Time Dilation "at rest"? Isn't that a constant? How do you measure time dilation at rest? Is your's the same as mine??

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Isn't "Time Dialation" just like all other aspects regarding faster than light travel, supermassive gravity wells (black holes) and their forces simply based on the POV of the observer to the phenomenon? In all reality the crushing forces (supposedly) of black holes or how time is perceived by the traveler (during time dialtion)all in relationship to the person experiencing the phenomenon and can be (as has been proposed) different looking and mesureably different than what the traveler experiences. This has been suggested by scientists that when an observer comes ever closer to the event horizon of a black hole they would see the ship begin to slow down while the traveler continues on.

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I just read a thread on another forum that is feeding some egos but in practice it ends up having no practical value in the future at least to me it seems right now. Dr. Bae device is interesting, and that is all the other scientist(s) said about it. To move mass in SpaceTime as he suggest just won't be practical at least to me. It is funding provided by NASA while they look at it, but to me in the end, it will be hype and then fall through to achieve anything practical. (15 minutes of fame?)

I think that you will just have to read up more about time travelling and there are books out that also give some theories about it.

Of course it is all theory yet, but it usually is never heard about again as in the case of Dr. Bae at least as it seems to me right now but that will be in the future. It is not the fact that it could not achieve anything, but to me the reason that it won't is because the supporting systems needed will not let it become anything practical anytime soon. To put it all together will take more science just as in the case of Time Travelling with a practical method.

It just becomes not practical to solve the SpaceTime travelling this way at this time.

The only reason that I post something else (forum) is because looking up the info takes too long, and there is too much of it -- Internet Overload, I guess.

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Watch Out! There are new batteries in my synths. This is a Warning! Watch Out!

When I turned it on I thought something had gone wrong since it has been so long, it was all out of tune. Why it defaults to scaled pitches is strange to me, but then, that can be changed back to normal pitches humans are use to hearing. It does remind me though, that if I want to, I can really be a spacealien and create some music again that really no human may want to listen to with out-of-tune scaled pitches. It was really strange because the notes were all like crazy to listen to.

I do have one dead upper black key note though. Say a prayer for my dead upper black key G#. Of course it probably can be fixed, but I suppose I would have to send it back to the factory. Well, while I am musing the unlikely prospect of buying just a keyboard (synthwise or like a piano keyboard) I will just have to assume that actually I will not have money for that. But if I did, I could still use all of the rest of it. The key kind of works somewhat, but that is those electronic devices and I have to spend my money on other things right now. Nothing is cheap in that endeavor, and my music will never be Great anyway. Maybe with all this time travelling talk I will just go crazy on the tones and settings of these synths and really come out with something strange. I doubt if all that many people will want to listen to it though. It would seem crazy to them, but then again, why buy a musical synth if a person wanted a regular instrument? That is why they were made in the first place. Because all the electronics make them a strange muscial instrument to begin with. I mean -- look up the Moog Synth created by Dr. Moog, now deceased, I think. Did he create this jumble of connecting telephone phone jacks lines to be the same as some other type of intrument created in the Past like a violin like a Stradavirius (spelling?)? Heck no!

:yum:

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bogz,

So I think it says if you can get to a velocity of 2c^2 (impossible, I know) the rate of change of time goes in reverse at the same rate time was passing when the object was at rest.

Traveling at two times the square of the speed of light (2*c^2) you'd be traveling, not ~300,00 km/sec, but 180,000,000,000 km/sec. That's several orders of magnitude above the speed of light.

The problem with traveling at the speed of light for objects that have an intrinsic rest mass is the "Lorentz Factor". The mass of an object is not set in stone. It is determined by its relative velocity given by:

m = E/c^2 * Gamma (the Lorentz Factor = sqrt 1 - (v^2/c^2)).

The problem here is that the Lorentz Factor at the speed of light is infinity. The mass of the object, as it approaches the speed of light approaches infinity. Mass also equates to inertia. Inertia is the property of mass that resists further increases in velocity. If the inertia approaches infinity then the ability to further increase velocity approaches zero. At the speed of light, for objects that have intrinsic rest mass, the energy input required to accelerate the mass to the speed of light increases to infinity.

This is the definition of the speed of light. No matter how much energy you add to the mix you still lack an infinite amount of energy to push the object over the top of the energy hill.

As I said in my previous post, the speed of light is not a barrier. It is a boundry. There's nothing that you can do to push the fictitious barrier aside. All you can do is brush up against the boundry and if you have infinite energy available you can turn time into space (on a light cone, you become a "lightlike object" if you had infinite energy available).

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Traveling at two times the square of the speed of light (2*c^2)

Ok I read the page a 2nd time. I meant moving at 2c, a 1 second event appears to take -1 second. Lorentz factor prevents moving => c. So are there any other time dilation equations or is it unique?

sqrt 1 - (v^2/c^2))

So imaginary numbers don't help here, for taking the sqrt of something < 0?

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but what about slowing light down? is the speed of light still the speed of light even when slowed?

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ruthless,

but what about slowing light down? is the speed of light still the speed of light even when slowed?

The speed of light is given as in vacuo - in a vacuum. That's the speed of propogation of the photon when it is freely moving between other particles. It appears to be slowed when it encounters other materials and that is given as the Index of Refraction. But what's really occuring is the photon is absorbed and re-emitted and its path is changed as it moves between other particles (electrons for the most part). But the photon is always moving a v~300,000 km * sec^-1.

This action of photons being absorbed and re-emitted and having the path changed is precisely what goes on in a star. A photon should only take about 8 minutes to arrive on Earth after it is first emitted in the solar core. In actuallity it takes tens of thousands of years to a million years to migrate along the speed of light random walk path to the surface. Then it's an 8 minute journey to Earth.

So the answer to your question is that the speed of light is fixed and isn't a function of the material that the photon is passing through. It only appears to be slowed if you are measuring the total elapsed time for the photon to pass into the material at one point until it exits the material at another point because you might be mislead into thinking that the photon moves in a straight line through the material and is never absorbed/emitted by the material.

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Re: Question regarding the paradox of time travel *DELETED*

Post deleted by TimeLord

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Timelord,

Hypothetically, if an object's velocity was imaginary, its relativistic mass could be smaller than its rest mass. I think this would correspond to the object moving in time

Correct. You've defined a timelike object in a tachyonic universe. It looses energy to speed up and gains energy to slow down. Though it can never be at rest, its greatest momentum is when its velocity approaches zero and is least when its velocity approaches C.

If you lived in that universe it would look the same to you as this universe looks to us. You would be made from the same "stuff" that everything else in that universe is made from- matter that has the property of negative mass and travels though negative space and imaginary time.

That's just a switch in signitures - a symmetry of reflection. Nothing unusual for the inhabitants of that universe. It would appear to them that they add energy to speed up and remove energy to slow down because they are "adding" negative energy to slow down and "subtracting" negative energy to speed up.

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Hello----viewing this site to learn more on time travel. All info would be of value.

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Cool, i was about to start my own thread but this one seems cool to use.

Hmm. Where to start... now im lost ><

This paradox thing can be real confusing especially that grandfather paradox thing.

If event1 interferes with a past event2 then how would that event1 even exist?

That makes me think then why does it have to be event for a change in worldlines?

Wouldnt it be that endless amounts of worldlines are being created right now no matter what events happen?

This alone raises endless amount of questions on my behalf at least.

If there are worldlines then where the hell are we or better, where am i now?

In which worldline do i exist or do i exist in all or is my consciousness just in one place?

Hate to think there would be one place where i would be a bad person but would that person really be me?.

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The possibilities of alternate worlds with our same life force just traveling along on different paths is a question that was posed in the movie The One. Oddly enough to make things somewhat beleivable and far less complex they only had approx. 130-140 alternate universives. Unfortunately real life would not be confined to this set number of universes. What I wonder is if all universes run along a specific time frame that is mirrored to ours or can they run at half speeds, twice our speed? And if you can time travel would it not be more likely that you would travel in time to through your own universe (especially if time runs differently in other universes)because then the question comes in that if there are (hypothetically) an infinite number of alternate universes for every choice we could make, and we travel to that one (randomly as we have not even discussed on how to choose the universe that you would travel to) how could you possibly hope to go back to your same universe based on the fact that you randomly travel to universe x and you want universe y in an infinite pool of universes??

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