### Author Topic: Any resolutions to FTL paradoxes?  (Read 82202 times)

#### meberbs

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##### Re: Any resolutions to FTL paradoxes?
« Reply #40 on: 07/21/2017 05:39 pm »

The only thing logically impossible is FTL.

Never say something is impossible because sooner or later, someone or something comes along and proves you wrong.
Generally a good point, I don't like the word "impossible."

Note that I was using words to mirror WarpTech's statement. Also, "logically impossible" basically just means illogical. Under a given base assumption, it is clearly possible to determine if something is illogical. Using nothing but the principle of relativity (no preferred reference frame), you can show that FTL is illogical.

#### WarpTech

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##### Re: Any resolutions to FTL paradoxes?
« Reply #41 on: 07/21/2017 06:04 pm »

The only thing logically impossible is FTL. You seem to claim that the difference between the time ship 1 enters FTL and the time ship1 exits FTL is the same in both frames even though time is flowing differently in both frames (earth frame and ship 2 initial frame). That is illogical.

To get from my unprimed frame to yours, just subtract 5 weeks from t and 10 light years from x. To get from my primed frame to yours, add 483 weeks to t' and subtract 13.902 lightyears from x'. As they should, the effect of the results does not depend on the choice of origin.

Since you insist, lets use your 2 coordinate systems. The coordinates of the event "ship 1 enters FTL" in the unprimed frame at x = -500 light-weeks (10 light-years), t = -5 weeks

(c = 1 light-week per week)
t' = 1.4*(-5 - 0.7c*-500/c^2) = 1.4*(-5+0.7*500) = 483
x' = 1.4*(-500-0.7*-5) = -695.1 light-weeks = -13.902 light-years

Unsurprisingly, this result is exactly equivalent to what I calculated before.
The switching of past and future is expected, because FTL entrances and exits occur in a space-like interval, not a time-like one. This causes no logical problems as long as you don't have FTL travel.

Idk, but it seems to me that your math is flawed. The proper length of the trip is the length of the path in the "rest frame" of Earth. If the distance from where ship 1 exited FTL and Earth is 500 light weeks (10 light years) in the rest frame. Then, in the frame of ship 2 passing ship 1 where it exits FTL is t=t'=0, the distance to Earth is then shorter, not longer;

L = 10 ly/1.4 = 7.1 ly

If you want to resolve the paradox, you need to make the S and S' systems coincident at the same Event in space-time. The location where ship 1 and ship 2 are at the same place, at the same time is when ship 2 receives the signal from ship 1. This is defined as the origin where the x, t coordinates of ship 1 and ship 2 are the same, where x=x'=t=t'=0. Since t=t'=0, then v*t=v*t'=0.

Now, from this point, the distance to Earth is 7.1 ly in the primed frame. Which is shorter than it is in the unprimed frame. When ship 2 engages FTL toward Earth, it will arrive at Earth in 3.57 weeks, still moving at 0.7c relative to Earth after it exits FTL. The signal will be received by Earth 8.57 weeks AFTER ship 1 left.

There is no reference frame where ship 1 and ship 2 are at the same place, but ship 2 is years in the past of ship 1. Ship 1 moving at FTL did not bring it out of FTL in the past, the FTL warp drive I propose has the clock on the ship 1 ticking at the same rate as the clock back on Earth.

#### ppnl

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##### Re: Any resolutions to FTL paradoxes?
« Reply #42 on: 07/21/2017 06:22 pm »

Quote
According to Ship 2 when ship 1 exits FTL, it is still years before ship 1 had entered FTL, no matter where you choose the origin of this frame.

is logically and physically impossible. If this is what the Lorentz transformation is telling you, you're doing something wrong.

It really really seems illogical doesn't it? But that really is how it works. And as long as you allow no speed faster than light then there are no paradoxes and so while it is weird it isn't illogical.

Now you can claim that relativity must be wrong in some way. But first you need to show that you understand what relativity is claiming. From the look of it you don't.

#### meberbs

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##### Re: Any resolutions to FTL paradoxes?
« Reply #43 on: 07/21/2017 06:27 pm »

The only thing logically impossible is FTL. You seem to claim that the difference between the time ship 1 enters FTL and the time ship1 exits FTL is the same in both frames even though time is flowing differently in both frames (earth frame and ship 2 initial frame). That is illogical.

To get from my unprimed frame to yours, just subtract 5 weeks from t and 10 light years from x. To get from my primed frame to yours, add 483 weeks to t' and subtract 13.902 lightyears from x'. As they should, the effect of the results does not depend on the choice of origin.

Since you insist, lets use your 2 coordinate systems. The coordinates of the event "ship 1 enters FTL" in the unprimed frame at x = -500 light-weeks (10 light-years), t = -5 weeks

(c = 1 light-week per week)
t' = 1.4*(-5 - 0.7c*-500/c^2) = 1.4*(-5+0.7*500) = 483
x' = 1.4*(-500-0.7*-5) = -695.1 light-weeks = -13.902 light-years

Unsurprisingly, this result is exactly equivalent to what I calculated before.
The switching of past and future is expected, because FTL entrances and exits occur in a space-like interval, not a time-like one. This causes no logical problems as long as you don't have FTL travel.

Idk, but it seems to me that your math is flawed. The proper length of the trip is the length of the path in the "rest frame" of Earth. If the distance from where ship 1 exited FTL and Earth is 500 light weeks (10 light years) in the rest frame. Then, in the frame of ship 2 passing ship 1 where it exits FTL is t=t'=0, the distance to Earth is then shorter, not longer;

L = 10 ly/1.4 = 7.1 ly
Yes, that is the current distance between ship 2 and Earth in the ship 2 frame, as you will see I had already calculated by a different method. The problem is your baseless assumption that "now" in the ship 2 frame corresponds to shortly after ship 1 left Earth. In the ship 2 frame, Earth is moving away from ship2 at 0.7 c, and will move quite a few light years in the 483 weeks that will pass before ship 1 leaves Earth.

If you want to resolve the paradox, you need to make the S and S' systems coincident at the same Event in space-time. The location where ship 1 and ship 2 are at the same place, at the same time is when ship 2 receives the signal from ship 1. This is defined as the origin where the x, t coordinates of ship 1 and ship 2 are the same, where x=x'=t=t'=0. Since t=t'=0, then v*t=v*t'=0.
I did that, as I showed picking "ship 1 exits FTL" as the origin creates the same result as picking "ship 1 enters FTL." Because as long as it is consistent why should the choice of origin matter?

Now, from this point, the distance to Earth is 7.1 ly in the primed frame. Which is shorter than it is in the unprimed frame. When ship 2 engages FTL toward Earth, it will arrive at Earth in 3.57 weeks, still moving at 0.7c relative to Earth after it exits FTL. The signal will be received by Earth 8.57 weeks AFTER ship 1 left.
The first half of this is correct, and matches what I already said. The second half makes no sense, because t=-5 is the time coordinate of ship 1 leaving earth in the unprimed frame.  You never bothered to figure out what the time coordinate is in the unprimed frame (t'=483  weeks as I showed) Adding time coordinates of different reference frames is simply wrong.

There is no reference frame where ship 1 and ship 2 are at the same place, but ship 2 is years in the past of ship 1. Ship 1 moving at FTL did not bring it out of FTL in the past, the FTL warp drive I propose has the clock on the ship 1 ticking at the same rate as the clock back on Earth.
Stop talking about the clock on ship 1, I don't care what it says, it does not matter. According to ship 2, ship 1 exited FTL years before it entered it, and nothing internal to ship 1 changes that.

You say "it seems to me that your math is flawed" but you couldn't actually point to a flaw. I pointed to multiple flaws in your math.

#### WarpTech

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##### Re: Any resolutions to FTL paradoxes?
« Reply #44 on: 07/21/2017 08:42 pm »

Quote
According to Ship 2 when ship 1 exits FTL, it is still years before ship 1 had entered FTL, no matter where you choose the origin of this frame.

is logically and physically impossible. If this is what the Lorentz transformation is telling you, you're doing something wrong.

It really really seems illogical doesn't it? But that really is how it works. And as long as you allow no speed faster than light then there are no paradoxes and so while it is weird it isn't illogical.

Now you can claim that relativity must be wrong in some way. But first you need to show that you understand what relativity is claiming. From the look of it you don't.

Now I understand why @meberbs was confused about ship 2 moving away vs moving toward the earth. In the frame of ship 2, moving away from Earth, at 0.7c, the event of ship 1 leaving Earth and entering FTL is in the future. When it turns around to deliver the message, the primed space-time axis flip to -0.7c, moving toward the Earth. In this frame, the event of ship 1 leaving Earth is in the past.

One can think of an FTL signal as being identical to an FTL ship. If ship 2 emits an FTL signal or FTL ship 3 back toward Earth, the space-time axes still flips from v to -v. In the frame of the signal and the event of ship 1 leaving Earth is still in the past. Ship 2, nor the signal it sends to Earth can travel backwards in time.

#### meberbs

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##### Re: Any resolutions to FTL paradoxes?
« Reply #45 on: 07/21/2017 09:22 pm »

Quote
According to Ship 2 when ship 1 exits FTL, it is still years before ship 1 had entered FTL, no matter where you choose the origin of this frame.

is logically and physically impossible. If this is what the Lorentz transformation is telling you, you're doing something wrong.

It really really seems illogical doesn't it? But that really is how it works. And as long as you allow no speed faster than light then there are no paradoxes and so while it is weird it isn't illogical.

Now you can claim that relativity must be wrong in some way. But first you need to show that you understand what relativity is claiming. From the look of it you don't.

Now I understand why @meberbs was confused about ship 2 moving away vs moving toward the earth. In the frame of ship 2, moving away from Earth, at 0.7c, the event of ship 1 leaving Earth and entering FTL is in the future. When it turns around to deliver the message, the primed space-time axis flip to -0.7c, moving toward the Earth. In this frame, the event of ship 1 leaving Earth is in the past.

One can think of an FTL signal as being identical to an FTL ship. If ship 2 emits an FTL signal or FTL ship 3 back toward Earth, the space-time axes still flips from v to -v. In the frame of the signal and the event of ship 1 leaving Earth is still in the past. Ship 2, nor the signal it sends to Earth can travel backwards in time.
Ship 2 does not accelerate or change direction before engaging its FTL drive. It is sitting in its rest frame, it doesn't even make sense to say it "turned around", since it isn't moving. Don't think about anything other than this initial rest frame or you will confuse yourself, like you have been doing all thread.

In this frame, all it does is activate its FTL drive aimed at a point just over 7 light years to the left. It arrives between 3 and 4 weeks later in this frame. However, in this frame, ship 1 does not leave Earth for over 479 more weeks.

It does not matter that the Earth is moving, except for calculating the exact distance it wants to travel in FTL, the ship isn't planning to stop on Earth.
« Last Edit: 07/21/2017 09:28 pm by meberbs »

#### KelvinZero

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##### Re: Any resolutions to FTL paradoxes?
« Reply #46 on: 07/22/2017 01:30 am »
The only thing logically impossible is FTL.
Never say something is impossible because sooner or later, someone or something comes along and proves you wrong.
Rather than say "impossible", a better word is perhaps "undefined" or "apparently paradoxical".

In a way, "undefined" is even more damning than "impossible", because people who claim FTL is possible without defining what happens when apparent paradoxes are implimented are making a statement without meaning.

On the other hand, unlike "impossible", We can validly say FTL is undefined, and this statement will not be refuted even if in the future it becomes defined. Our statement will remain true in the context it was given, when FTL did not have this definition.

(edit)
btw, Im thinking that this topic might be better if changed specifically to trying to contrive some paradox preventing rules. Possibly even moved to the entertainment section and expressed as FTL rules for HardSF writers.

When I started the topic here I was hoping for published work about resolving paradoxes. The thread has been somewhat derailed by people who won't even admit there is an issue to discuss.
« Last Edit: 07/22/2017 02:57 am by KelvinZero »

#### dustinthewind

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##### Re: Any resolutions to FTL paradoxes?
« Reply #47 on: 07/22/2017 02:41 am »
The only thing logically impossible is FTL.
Never say something is impossible because sooner or later, someone or something comes along and proves you wrong.
Rather than say "impossible", a better word is perhaps "undefined" or "apparently paradoxical".

In a way, "undefined" is even more damning than "impossible", because people who claim FTL is possible without defining what happens when apparent paradoxes are implimented are making a statement without meaning.

On the other hand, unlike "impossible", We can validly say FTL is undefined, and this statement will not be refuted even if in the future it becomes defined. Our statement will remain true in the context it was given, when FTL did not have this definition.

Or maybe it has been defined by some one, but is buried under mountains of knowledge and we just don't realize it yet.  Maybe its already defined, but in a galaxy far far away (just not here).  Maybe it just hasn't yet been applied, but then again maybe it could already be applied in a galaxy far far away.  Supposing it is, maybe that isn't such a great distance any more?  Well at least we know that we, ourselves, don't yet know how to put it into practice if its possible.  I'm sure a lot of us here hope to see it openly applied during our lifetimes if its possible.  It would be quite depressing if it isn't.  Let's hope.

#### dustinthewind

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##### Re: Any resolutions to FTL paradoxes?
« Reply #48 on: 07/22/2017 03:22 am »
I think they key to understanding what WarpTech is saying is that locally he his modifying the passage of time and speed of light.  Well in a way it is non-locally modifying it.  The occupants should be unaware of this change in the speed of light locally.

Normally for a ship moving away as it gains speed, space time contracts for the ship and its time slows down.  However for the ship occupants its time does not slow down, its the universes time that speeds up ... well (speeds up and slows down) speeds up because they end up in the future.  How does this happen?  It's during the contraction phase.  For the space in front of the ship to contract and become closer, you must take the forward velocity of the ship and add time, and the further away the more time you add, and everything uniformly contracts.  This would signify traveling into the future.  So realistically you can go as fast as you want in your own ship.  At first you travel mostly through space but at the c limit you begin more traveling through time/space.  (more through time).

By locally stretching the ship and modifying the index instead you also appear to contract space outside to someone aboard the ship, but you do this by expanding your ship and locally increasing the speed of light (increasing your ruler w.r.t the universe).  To increase the speed of light means increasing the passage of time and decreasing your mass.  Having some velocity and decreasing your mass means your velocity increases but now your speed limit also increases.  If you balance relativity effects and this index you can keep your index the same as some one else's far away so you both age at the same rate.

Such a method would allow you to achieve the same "apparent" relative velocity w.r.t. the universe as you would via being limited to the speed of light except now you can make the trip there and back, still being alive and having exceeded the light speed limit, and return the same linear age as your relatives when you return.

What it would take to accomplish this however is the big kahuna.  I think WarpTech calls it pumping energy into the ZPF?  It can probably be thought of as locally inflating the vacuum.
I'm hoping i'm not too far off and that helps clarify the concept.
« Last Edit: 07/22/2017 05:52 am by dustinthewind »

#### KelvinZero

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##### Re: Any resolutions to FTL paradoxes?
« Reply #49 on: 07/22/2017 04:06 am »
Or maybe it has been defined by some one, but is buried under mountains of knowledge and we just don't realize it yet.
That is equivalent to being undefined. The whole point of definitions is that two people can use them to converse, using words, that have agreed definitions.

(I suspect a corollary to the rule "Any internet conversation will eventually descend into semantics" is that eventually the discussion of semantics will have to descend to an attempt to define the word "defined")

It really does not need to be this confusing. What I am looking for is descriptions of what happens when someone tries to implement one of the paradoxes. How are the apparent paradoxes resolved. What. Actually. Happens.

#### RonM

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##### Re: Any resolutions to FTL paradoxes?
« Reply #50 on: 07/22/2017 05:22 am »
It really does not need to be this confusing. What I am looking for is descriptions of what happens when someone tries to implement one of the paradoxes. How are the apparent paradoxes resolved. What. Actually. Happens.

In General Relativity, the paradoxes due to assuming FTL travel indicates FTL travel won't work. You can't implement the paradox. If FTL is possible, it's new physics requiring new theories to improve on GR. Without new theories, you can't get past the paradoxes.

#### KelvinZero

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##### Re: Any resolutions to FTL paradoxes?
« Reply #51 on: 07/22/2017 07:45 am »
In General Relativity, the paradoxes due to assuming FTL travel indicates FTL travel won't work. You can't implement the paradox. If FTL is possible, it's new physics requiring new theories to improve on GR. Without new theories, you can't get past the paradoxes.
Very possibly, but there might be loopholes. I think (just a layman's guess) one possible loophole could be to move your 'stargate' ends so far apart that the expansion of the universe puts them into otherwise causally disconnected parts of the universe. I think the paradoxes would not be implementable in that case.

There might be less extreme examples.

#### meberbs

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##### Re: Any resolutions to FTL paradoxes?
« Reply #52 on: 07/22/2017 04:27 pm »
In General Relativity, the paradoxes due to assuming FTL travel indicates FTL travel won't work. You can't implement the paradox. If FTL is possible, it's new physics requiring new theories to improve on GR. Without new theories, you can't get past the paradoxes.
Very possibly, but there might be loopholes. I think (just a layman's guess) one possible loophole could be to move your 'stargate' ends so far apart that the expansion of the universe puts them into otherwise causally disconnected parts of the universe. I think the paradoxes would not be implementable in that case.

There might be less extreme examples.
There would also need to be some mechanism that would prevent opening up a second "stargate" in parallel that has some relative velocity to the first. And this mechanism would need to be restricted in its ability to transmit FTL information. It might be possible, but I haven't figured out the right way to put these restrictions down formally. This causality protection mechanism would almost certainly require some new theory.

I have seen serious suggestions that if you created a closed timelike loop using wormholes, some sort of feedback mechanism would cause the wormholes to collapse. Specifically, the wikipedia pageon chonology protection references a book on GR called "Black Holes and Time Warps" which apparently proposes a specific mechanism involving vacuum fluctuations, but this sounds like it would require quantum gravity to truly analyze, which is a theory that doesn't exist yet.

#### meberbs

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##### Re: Any resolutions to FTL paradoxes?
« Reply #53 on: 07/22/2017 04:40 pm »
Such a method would allow you to achieve the same "apparent" relative velocity w.r.t. the universe as you would via being limited to the speed of light except now you can make the trip there and back, still being alive and having exceeded the light speed limit, and return the same linear age as your relatives when you return.
The paradoxes don't care anything for how much time passes on the ship though, it could be 1 second or 100 years, and the paradox would remain a problem. "relative velocity w.r.t. the universe" implies that there is a special frame associated with "the universe" when there isn't.

WarpTech's explanations just ignore or deny the existence of frames where the FTL travel is travel backwards in time, allowing someone in that frame to use their FTL to create a loop. He has demonstrated that he has no idea what he is talking about when it comes to special relativity, and until he understands the problem, there is no way he can address it.

#### ppnl

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##### Re: Any resolutions to FTL paradoxes?
« Reply #54 on: 07/22/2017 10:52 pm »
I think they key to understanding what WarpTech is saying is that locally he his modifying the passage of time and speed of light.  Well in a way it is non-locally modifying it.  The occupants should be unaware of this change in the speed of light locally.

But that just can't matter. The time dilation, time offset and space contractions aren't some physical effect that is mechanically caused by your motion. It is geometry. You cannot speak of being in your neighbor's house across the road without being across the road. It is nonsense to think that some kind of warp drive will let you visit your neighbor without you being across the road. Warp drive, teleporting or magic poofing just can't matter. It makes no difference.

Similarly relativity pretty much defines traveling faster than light as time travel. If you can do it then you can return home before you left. This isn't a mechanical effect of speed or acceleration that you might find some way to prevent. It is an unavoidable property of the geometry of spacetime. Warp drive, teleporting or magic poofing just can't matter.

To do it you will have to break and disprove relativity and dump that geometry. Well I'm all for that if it can be done but you first have to understand the problem.

#### dustinthewind

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##### Re: Any resolutions to FTL paradoxes?
« Reply #55 on: 07/22/2017 11:30 pm »
I think they key to understanding what WarpTech is saying is that locally he his modifying the passage of time and speed of light.  Well in a way it is non-locally modifying it.  The occupants should be unaware of this change in the speed of light locally.

But that just can't matter. The time dilation, time offset and space contractions aren't some physical effect that is mechanically caused by your motion. It is geometry. You cannot speak of being in your neighbor's house across the road without being across the road. It is nonsense to think that some kind of warp drive will let you visit your neighbor without you being across the road. Warp drive, teleporting or magic poofing just can't matter. It makes no difference.

Similarly relativity pretty much defines traveling faster than light as time travel. If you can do it then you can return home before you left. This isn't a mechanical effect of speed or acceleration that you might find some way to prevent. It is an unavoidable property of the geometry of spacetime. Warp drive, teleporting or magic poofing just can't matter.

To do it you will have to break and disprove relativity and dump that geometry. Well I'm all for that if it can be done but you first have to understand the problem.

If your clock ticks at the same rate at home as for you aboard the ship by locally modifying your local index K you don't return home before you left.  You return as fast as you can travel, (speed no longer limited by c) and eliminate relativistic effects that limit your velocity.  It appears the concept is linked to some of Harrold Puthoff's work.

One of Puthoffs papers: https://scholar.google.com/scholar?cluster=17157422968110203841&hl=en&as_sdt=0,26

I also found it somewhat amusing a ufo abductee claimant wrote equations in their sleep related to Puthoff's equations.  http://synchronizeduniverse.com/STAN%20ANALYSIS3.pdf  written by By Dr. Claude Swanson .

The whole problem of assuming your moving backwards in time is probably because your not eliminating relativistic effects and still assuming your exceeding c.  In such a case you can go back in time but takes more than infinite energy and is impossible.  Basically inverting time and space so you go back in time.  You cant relativistically exceed c.

The idea of eliminating relativistic effects is that you still have relativity but as you increase your velocity and K would increase, you purposefully modify K such that it remains the same as where you left.  Relativity superimposed with lowering K = constant K.  Your speed can continue to increase with out an increase in mass or slowing in time but it manipulates the vacuum.  Is the vacuum really manipulable in this way?

Regardless of what some think, the vacuum does appear to have associated frames, though the vacuum doesn't always have the same frame locally.  Take for instance frame dragging.  These define the local C speed limit of counter propagating light waves.

« Last Edit: 07/22/2017 11:32 pm by dustinthewind »

#### meberbs

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##### Re: Any resolutions to FTL paradoxes?
« Reply #56 on: 07/23/2017 12:23 am »
The whole problem of assuming your moving backwards in time is probably because your not eliminating relativistic effects and still assuming your exceeding c.  In such a case you can go back in time but takes more than infinite energy and is impossible.  Basically inverting time and space so you go back in time.  You cant relativistically exceed c.
It is not turning off relativistic effects for the ship that is required to fix the problem. It is turning off relativistic effects for the entire universe. Since we have observed relativistic effects, this is contradictory.

Your post reads as if you haven't read a single post in this thread from any of the people who understand relativity, including the one you quoted.

Regardless of what some think, the vacuum does appear to have associated frames,
regardless of what you think, this statement is false. This has been proven by experiment. And "frame dragging" is not some kind of exception. It does not mean one frame is special, it means that all frames (which are all equally valid) are bent by a rotating massive object.

You might want to learn what you are talking about before making statements that both prove your ignorance and make it sound like you think all physicists are idiots. (Because that is what I hear when you claim that the very basis of both special and general relativity is wrong.)

#### dustinthewind

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##### Re: Any resolutions to FTL paradoxes?
« Reply #57 on: 07/23/2017 01:46 am »
The whole problem of assuming your moving backwards in time is probably because your not eliminating relativistic effects and still assuming your exceeding c.  In such a case you can go back in time but takes more than infinite energy and is impossible.  Basically inverting time and space so you go back in time.  You cant relativistically exceed c.
It is not turning off relativistic effects for the ship that is required to fix the problem. It is turning off relativistic effects for the entire universe. Since we have observed relativistic effects, this is contradictory.

Your post reads as if you haven't read a single post in this thread from any of the people who understand relativity, including the one you quoted.

Regardless of what some think, the vacuum does appear to have associated frames,
regardless of what you think, this statement is false. This has been proven by experiment. And "frame dragging" is not some kind of exception. It does not mean one frame is special, it means that all frames (which are all equally valid) are bent by a rotating massive object.

You might want to learn what you are talking about before making statements that both prove your ignorance and make it sound like you think all physicists are idiots. (Because that is what I hear when you claim that the very basis of both special and general relativity is wrong.)

It's not just the ship that has its time modified.  The whole reason the universe aboard the ship appears to contract is because "the universe is contracted by having your relative velocity and the further ahead the more time is added. (the further behind the more time is subtracted)"  The universe is now distorted in time.  You become a time traveler in the universe.  If you assume the rest of the universe contracts because of relativistic effects and you assume you exceed c you travel back in time which is an erroneous assumption.

By modifying your local index you actually stretch your ruler w.r.t. the universe while still Edit: counteracting the contracting the universe.  You no longer become a time traveler you become a space traveler.  Your home planet is not in your same frame, yet you manipulate your frame to match your originating frame's clock.  All other time in the universe passes as if you existed at home.

When you would have a gamma of 2 you might actually travel at twice the speed of light.
« Last Edit: 07/23/2017 04:09 pm by dustinthewind »

#### WarpTech

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##### Re: Any resolutions to FTL paradoxes?
« Reply #58 on: 07/23/2017 02:01 am »
It seems the problem is very similar to the Twins Paradox. See attached image I found online. I added the red and orange arrows to represent ship 1 and ship 2. However, this diagram is for 0.6c not 0.7c as we were discussing.

I added the direction of both ships after they exit FTL. This diagram shows the perspective from both sides.

#### KelvinZero

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##### Re: Any resolutions to FTL paradoxes?
« Reply #59 on: 07/23/2017 03:32 am »
In General Relativity, the paradoxes due to assuming FTL travel indicates FTL travel won't work. You can't implement the paradox. If FTL is possible, it's new physics requiring new theories to improve on GR. Without new theories, you can't get past the paradoxes.
Very possibly, but there might be loopholes. I think (just a layman's guess) one possible loophole could be to move your 'stargate' ends so far apart that the expansion of the universe puts them into otherwise causally disconnected parts of the universe. I think the paradoxes would not be implementable in that case.

There might be less extreme examples.
I have seen serious suggestions that if you created a closed timelike loop using wormholes, some sort of feedback mechanism would cause the wormholes to collapse. Specifically, the wikipedia pageon chonology protection references a book on GR called "Black Holes and Time Warps" which apparently proposes a specific mechanism involving vacuum fluctuations, but this sounds like it would require quantum gravity to truly analyze, which is a theory that doesn't exist yet.
haha.. I spent a while looking for the pageon chronology protection. pageon = "page on". Duh.
I guess you mean this:
https://en.wikipedia.org/wiki/Chronology_protection_conjecture

For this thread im not to worried about theory that allows FTL. I certainly could not understand it. I was just hoping that proponents of FTL could explain what they even meant by the word, by explaining what their proposals predict  you would experience if you tried to implement one of the famous paradoxes.

Im thinking that has proven unprofitable. Im actually considering reposing the question in the entertainment section as "Rules for FTL for HardSF writers". No concern for theory at all, just rules that prevent paradoxes, so a writer could create a consistant universe.

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