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That FTL means time travel meme by Pierre-Simon Laplace - Sat, 16 Dec 2017 22:22:45 EST ID:hGyQlc1t No.57130 Ignore Report Quick Reply
File: 1513480965587.gif -(117244B / 114.50KB, 323x402) Thumbnail displayed, click image for full size. 117244
I have a question regarding this:
If you look at this gif it shows you "backwards" travel:
The first "jump" after the first acceleration points into the direction that corresponds to the lower left quadrant of the previous reference frame leading to backwards time travel.
However: Drawing it into the upper right quadrant should be equally legal which would imply forward time travel. This would imply that direction you are moving in space would dictate the direction of the "time travel" which seems entirely non-sensical to me.
I guess this is also the point but I still get the feeling I'm missing something here.
>>
Starfox !!S9+xB2BS - Sat, 17 Mar 2018 10:48:06 EST ID:NY7j51D6 No.57242 Ignore Report Quick Reply
>>57130
You (and pretty much everbody else) are forgetting that relativity treats space and time as one, and how it does so... the gif is also completely wrong in how to describe it.

For starters: You are always moving through spacetime at the speed of light,as expressed by a simple formula:

v(time) + v(space) = c

As "c", the speed of light, is known to be a constant, as v(space) increases, you have to reduce v(time) and vice versa.
v(time) is the "velocity" you move through time with.
v(space) is what you would regularily know as velocity. This variable cannot be negative, as simply reversing your ship still implies a positive velocity, just in another direction.

if v(space) > c, time would only go backwards locally on your ship (since c is constant, and v(time) would nescessarily need to be negative), not to external observers, as their v(time) and v(space) remains normal.

However with this normal, "unprotected" FTL travel in our spacetime frame, would also dangerously violate local and universal causality:

Imagine you are the pilot, and you lauched the ship when you were 20 years old (for simplicity, on your 20th birthday)... you engage your "normal spacetime frame" FTL drive after travelling a few years (say on your 25th birthday.). This will quickly hit a wall, as the time frame inside the ship quickly moves to the point where you pressed the button for your FTL drive and the ship hit light speed... with the end effect being that when you press the FTL button, nothing will happen, short of you accelerating to c and never passing the barrier.

IF it WAS to work, you would end up at a point where the local timeframe of your ship would be at the point where you launched the ship... There would NOT be 2 of you, as time for everybody else passes normally, and outside it's still the day of your 25th birthday. But local (ship) causality dictates that you and the ship should be on the launchpad... That travel would end up with you ripping causality apart when you leave FTL, as you have created your own time frame and causality that is completely disjointed from the rest of the universe and any consequences thereof.... or with pre-fetal you and a bunch of rocks travelling at FTL speeds, yet with everything else progressing as normal... until those bits hit the local causal and temporal point of the Big Bang :-O

In order to travel at FTL speeds in the first place, you will have to do one of the following:
>change "c" by moving into another domain where "c" is different
this is the core concept of most fictional hyperspace mechanics, especially Babylon 5 hyperspace or Star Control hyperspace/metaspace
>change v(time) by moving into another domain where v(time) is also rendered negative or 0 for the rest of the universe
you WILL need to have a positive v(time) inside the ship or you will violate local causality or never be able to leave (because if v(time) = 0 you will be frozen in time and never be able to leave the domain
>disjoint space and time
which cannot happen in our spacetime frame,as you cannot exist without space to inhabit your body, or time to enable your travel
>teleport (essentially ignoring the space part)
theoretically teleporting can solve the problem, however it's very hard and energy expensive to do so... plus, you would logically die while your "copy" reached its target due to the rules of quantum teleportation.
>exploit space itself
by moving space around your ship instead of moving the ship itself... the core concept of the Alcubierre/warp drive, so far the only viable method of FTL travel. It does not violate any of the above. Space in itself is nothing and contains nothing.. it does not have a definable "age" and it does not perform any actions on itself or surrounding matter, in essence. even if space is a part of spacetime it is not affected by time, just as time does not affect space itself (only its contents).
As space itself is also not an "object", by creating a pocket of spacetime to store the ship in (and moving the pocket itself), you can exploit a very important property of space, that it can EXPAND and CONTRACT at FTL speeds (as it provably did during the Big Bang).

Another way of exploiting space would be to punch a hole through its very fabric (a wormhole) and create a shortcut through spacetime... however whether this is possible is still unknown, as we don't have any idea yet of what or where this shortcut should pass through.

this should put a suffieciently large nail in that coffin... either nothing happens or you (very unlikely) destroy the Universe by creating a new Big Bang, take your pick...
>>
Karl von Weizsacker - Sat, 17 Mar 2018 11:58:33 EST ID:xNrGsoxl No.57243 Ignore Report Quick Reply
>>57242

im not disputing you here, simply seeking more information. where did the formula v(time) + v(space) = c come from? this is the first ive ever seen or heard of it
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Starfox !!S9+xB2BS - Sat, 17 Mar 2018 14:29:00 EST ID:NY7j51D6 No.57244 Ignore Report Quick Reply
>>57243
the formula is a very boiled down version derived from Lorentz transformation without fancy greek letters, which explains many of the concepts and limitations of Lorenzian/Einsteinian relativity and of the speed of light, electromagnetism and causality (all of which are the same).

there has also been written a huuuuge number of papers in the last 100 years trying to explain why backwards time travel is impossible,at least in this manner...

A good starting point is Lorentz' papers on the subject and Appendix I of the original paper on special relativity from 1916: http://www.archive.org/stream/cu31924011804774#page/n159/mode/2up
it contains Einstein's derivation of Lorentz transformation.
>>
Karl von Weizsacker - Sat, 17 Mar 2018 16:47:17 EST ID:xNrGsoxl No.57245 Ignore Report Quick Reply
>>57244

would you mind hopping on /chem/ and replying to my thread about atoms

>>>/chem/79012
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George Gamow - Fri, 23 Mar 2018 02:51:59 EST ID:HiPCHEgP No.57271 Ignore Report Quick Reply
>>57244
I'm a bit confused as it simply characterizes the dialation of time relative to the observer. I'm a bit lost how we make the leap to backwards time travel. We know despite relative motions of any direction, c is constant. Does this imply a specific orientation of spacetime? A perceivable "against the grain"? So backwards time travel can be more comparable to a sort if "temporal redshift"?
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Friedrich von Struve - Tue, 03 Apr 2018 00:01:33 EST ID:o31eHyLZ No.57274 Ignore Report Quick Reply
>>57242
>>
James Elliott - Wed, 16 May 2018 13:48:13 EST ID:+G8ef2Iy No.57279 Ignore Report Quick Reply
>>57271
you're pretty much correct in your basic understanding of how the speed of light works, but where things are confusing you is that what you've stated only applies to things that aren't capable of reaching and traveling the speed of light. once you move faster than light, causality is necessarily reversed by our understanding of the laws of relativity.

you see, the speed of light has fundamentally less to do with light than it does causality. the speed of light is more accurately the speed of causality, and photons just happen to have their velocity restricted by that boundary. so while light travels that speed, it's light itself is secondary to the more essential nature underlying reality that is causality.

knowing this, to travel faster than light means to travel faster than causality. to move faster than that any slower than light observer that could measure the properties of your spaceship or whatever would witness your actions occurring in reverse and vice versa.

interestingly enough, all that matters when it comes to the speed of light/causality is reaching it and breaking through it... that is to say, to do so isn't possible. if something were to simply exist moving faster than the speed of light or FTL travel becomes available somehow, moving faster than it doesn't negate the particles moving faster than it from experiencing relativistic effects of their own with regards to the speed of light, they just simply travel through time in reverse with respect to everybody/everything traveling below the speed of light.
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James Elliott - Wed, 16 May 2018 14:00:10 EST ID:+G8ef2Iy No.57280 Ignore Report Quick Reply
1526493610393.jpg -(69378B / 67.75KB, 877x500) Thumbnail displayed, click image for full size.
>>57279
this graph of a function where you try dividing by zero is a good, visually intuitive way of understanding the concept. the asymptote represents the speed of light and causality, and the curves on either side represent the velocity of any given particles traveling along on either side of that barrier. they are never capable of reaching the asymptote and, as my pic states, the curves will continue without bounds out towards infinity.

velocities traveled faster than the speed of light presumably behave symmetrically in terms of relativistic effects with velocities traveled slower than the speed of ligh, only with the direction/flow of time being reversed.
>>
James Elliott - Wed, 16 May 2018 14:01:43 EST ID:+G8ef2Iy No.57281 Ignore Report Quick Reply
>>57280
behave symmetrically in terms of relativistic effects with respect to velocities traveled slower than the speed of light***
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Arno Penzias - Mon, 21 May 2018 13:08:09 EST ID:457vC2+I No.57282 Ignore Report Quick Reply
>>57280
WADR, the mathematical consequences of attempting to reach the speed of light is because we define the speed of light as the maximum speed. The function of the relation between the speed of a photon and a tachyonic neutrino wouldn't be asymptotic but would simply be a ratio.

So I think it's misleading to say that the speed of light is the "speed" of causality. Tachyons would still obey causality in respect to other tachyons, just in a flow that is apparently opposite to events as ordered from our perspective. A hyper tachyon that traveled twice the rate of a normal tachyon would travel further into the past than it from our perspective, but from the perspective of the tachyon it is merely going further faster in the same direction as the slow tachyon, so they would experience retrocausality rather than acausality. So it makes more sense to me to think of the speed of light as a 180-degree 'fold' in causality, rather than a limit beyond which causality doesn't extend.
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Vera Rubiin - Tue, 26 Jun 2018 17:34:33 EST ID:zR0DYAV9 No.57316 Ignore Report Quick Reply
>>57282
i pretty much stated what you did in your post already, only i wasnt careful when regarding how i explained causality. the asymptote would represent the speed of light and the speed of causality as it relates to all sub-light speed forms of energy and matter, whereas on the other side of the asymptote it relate oppositely in equal proportion to all forms of matter and energy that exist moving faster than the speed of light.

in either cause, the lightspeed and causality barrier there would still exist and no form of matter or energy on either side of the asymptote would be capable of passing through the barrier. they could approach the barrier infinitely, but they would never reach it or pass through it. that's why the asymptote there is appropriate. sure, my usage of terminology was a bit lazy and sloppy, but really i feel like your nitpicking here is a bit strange. the speed of light, like the speed of sound, both represent barriers--the light barrier and the sound barrier. The speed of causality would be the same: the causality barrier.

The sound barrier is capable of being reached and crossed, but the speed of light is different... special. if we recognize as well that it is the speed of causality, it's just as different and special because it's literally just the exact same speed and barrier. it can neither be reached or crossed, but i mentioned that anything on the opposite site of the barrier, that is, any form of energy or matter that simply exists already moving faster than the speed of light or causality, would experience the same but opposite effects symmetrically and proportionally to any forms of matter or energy that exist moving below the speed of light/causality. the causality/light barrier merely represents a point at which all things on one particular side of the barrier will react relatively the same way to all other things on that site of the barrier when it comes to how they behave when approaching said barrier. this does not preclude tachyons from experiencing a form of causality, but rather experiencing causality moving forward on their side of the barrier (which everything on the sub-light speed side moving backwards through time relative to them and events happening causally in reverse with their effects happening before their causes), and likewise on the otherside everything moving forward in normal causality for them with things on the super-light speed side happening in reverse.
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Bernard-Ferdinand Lyot - Tue, 26 Jun 2018 17:45:40 EST ID:457vC2+I No.57317 Ignore Report Quick Reply
>>57316
I didn't intend my post as a counter or refutation to yours, but as an expansion that elaborated a little on the relationship between the mathematics and our common-sensical experience of events. I was merely highlighting that the distinction between our technical and colloquial understandings of these terms could potentially lead someone not as familiar with the subject off track. That's why we seemed to be saying the same thing.
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Thomas Gold - Wed, 27 Jun 2018 14:14:01 EST ID:0uLZJwlQ No.57318 Ignore Report Quick Reply
1530123241612.jpg -(84329B / 82.35KB, 500x701) Thumbnail displayed, click image for full size.
It is called tessellations moving in 5D nothing special so far

>inb4 i know hyperphysics debate me
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Solipsil - Tue, 17 Jul 2018 19:48:03 EST ID:5ItxfpYI No.57352 Ignore Report Quick Reply
>>57130
Maybe it doesn't make sense


The spice must flow
>>
Urbain Le Verrier - Sat, 11 Aug 2018 12:10:02 EST ID:y4EkzkGF No.57422 Ignore Report Quick Reply
What can we do to cease to exist here and then exist somewhere else faster than the distance of light without using wormholes?

Noob question I'm sorry.
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Edwin Hubble - Mon, 13 Aug 2018 16:30:39 EST ID:457vC2+I No.57428 Ignore Report Quick Reply
1534192239206.gif -(8760B / 8.55KB, 480x403) Thumbnail displayed, click image for full size.
>>57422
Quantum teleportation, but it really depends on your definition of 'we.' So far we can only do this with single particles.
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Johann Bode - Wed, 19 Sep 2018 20:17:06 EST ID:unNII3om No.57450 Ignore Report Quick Reply
>>57428

Something like that would be pure copying though. You'd actually be killed in the process.
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Christiaan Huygens - Sat, 22 Sep 2018 02:27:12 EST ID:457vC2+I No.57451 Ignore Report Quick Reply
>>57450
>>You'd actually be killed in the process
Hence
>>it really depends on your definition of 'we.
'You' could make it if 'you' are defined as the singular positions and velocity of your molecules at a given point in time. Not if 'you' means 'these specific atoms and the pattern they are arranged in.'

But here's the tickler for you; if there is no soul, and indeed consciousness is an epiphenomena of the interaction of the physicalistic systems of the brain, then the only thing that makes it seem as though you have a continuous stream of consciousness is that particular configuration of atoms converge to generate that phenomenon. Since your consciousness exists at the location of your brain wherever you are, if your brain, atom by atom, were teleported to another location literally in the same instance of planck time, there would literally be no way for the state of your brain to change or degrade in any way.

The key part of this is that there is nothing 'additional' to the life story two atoms of the same element at their resting state. No matter what you did, if you were not using other atoms as a way of encoding the story, would you be able to tell the two atoms apart. If you did the whole 'rip the beard off the evil clone and then mix them up' bit with two atoms of the same element, if you didn't have a camera tracking them, the information about which atom was which would be lost to the universe forever. I do not think that consciousness can be specific to the life history of a set of atoms -- it is specific to the pattern of a configuration of atoms, and in the same way the universe can't tell whether or not two resting state atoms are the same atoms they were before or different ones, so would your consciousness specifically and your brain in general have no way of telling if every single atom that composed it were swapped out with identical atoms. Indeed, it is important to remember that almost every single molecule in your body is recycled every couple of months, but your sense of continuity of consciousness isn't disturbed. So if continuity could persist with the atoms swapped out in place, why wouldn't it also persist if the swapping out occured between two locations, provided it happened at planck time scale?

So, if there is no 'mystical' property that generates consciousness, there is no reason to suspect that it couldn't survive the teleportation process, if the neurons that generate it survive that process. Alternatively, we must accept that there is some sort of non physical 'hidden variable' causing consciousness to operate the way it does.

Also, to fulfill Le Verrier's request, we would additionally need to find a way to send quantum information FTL, but one step at a time.
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Russel Hulse - Thu, 27 Sep 2018 17:46:18 EST ID:unNII3om No.57454 Ignore Report Quick Reply
>>57451

>'You' could make it if 'you' are defined as the singular positions and velocity of your molecules at a given point in time.

Which is not what I view as 'you'. We do agree on that consciousness is something else than the matter that give rise to it, but I think we have different perspectives on what truly is 'you'. And I don't think we should ignore the super-structured of matter, neural nets, which is the reason why personality and memories are so long lived.

I am well aware of the Ship of Theseus as a philosphical paradox, so let me clarify my position.
I see consciousness as primarily a process of interactions happening in time, in the form of interactions between structures of matter. It is a matter of causality, not the constituent atoms. As long as the super-structures and processes of those structures remains intact, 'you' are alive. The matter making up your brain can be constantly replaced, as long as the process itself is unbroken the fact that the wood of your ship today is not the wood when your ship was made does not matter.


Now perhaps I misunderstand quantum teleportation, and if I do please tell me. But as I see it, once that process is broken for even a planck-length of time, you're no more.
The information of you is transmitted, but the process that is you is obliterated.
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Harlow Shapley - Thu, 27 Sep 2018 18:20:40 EST ID:457vC2+I No.57455 Ignore Report Quick Reply
>>57454
>> But as I see it, once that process is broken for even a planck-length of time, you're no more.
The idea would be that it would occur simultaneously, with no break in operation.
Consider it this way -- people have been resuscitated from an utterly dead state, because their bodies were so cold that molecular motion slowed down so significantly that no advanced brain deterioration could occur. We assume that the person reanimated was the same person, and not some sort of psychic clone; because why would it be?
So if, prior to teleportation, your global body temperature reached absolute zero and stayed that way, it wouldn't matter if teleportation took a second or a thousand years, as long as every molecule was kept at absolute zero (ignoring the problem of ice crystal formation for now -- lets assume we're talking about a sentient robot, or perhaps a tardigrade like lifeform.)

>> as long as the process itself is unbroken
But that was the point of my previous post. I attempted to illustrate how the process that generates your consciousness has nothing to do with the particular atoms and everything to do with the pattern (process) in which they are arranged. So, in our hypothetical teleporter, all structures and structural processes remain intact. There is no lapsed period of operation -- at the smallest physical scale, both in space and time, there is no difference between the start and end configuration. By the fundamental definition of 'process' from a physics standpoint, nothing could be broken.

Which means we are left with two alternatives; either what you consider to be your consciousness is indeed the result of the pattern of configuration of your brain, which means that if that pattern of configuration is replicated exactly, the same phenomena arises -- like causes leading to like results, the foundation of empiricism. Alternatively, if consciousness did not persist through this transition, we would have to speculate as to why -- the most clear implication being that there is some 'hidden variable' beyond the physical configuration that enables the persistence of consciousness. Since, from a physicists standpoint, we believe that the physical universe is the only universe there is, it means either there is some form of matter or energy unknown to us that is necessary for consciousness to operate, or there is indeed something beyond the physical universe that enables that continuity.

Put the other way; when your brain physically moves through space, its configuration is continually changing in an amount vastly greater than occurs in a planck time before you even notice the passage of time at all. There must be some property that enables this continuity, and either it is a configuration of the physical components of the brain, or it is something beyond physics altogether. Confirming that we could teleport and survive would demand new physical explanations -- but discovering that we didn't survive would require an equally novel explanation under the current epiphenomenalism model, that's what I'm highlighting here.
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Bernard-Ferdinand Lyot - Thu, 27 Sep 2018 18:55:44 EST ID:3nlPOKZc No.57456 Ignore Report Quick Reply
>>57130
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Bart Bok - Sun, 30 Sep 2018 09:42:04 EST ID:9RKOIT3O No.57459 Ignore Report Quick Reply
>>57130
>However: Drawing it into the upper right quadrant should be equally legal
Equally illegal? ;)

>This would imply that direction you are moving in space would dictate the direction of the "time travel" which seems entirely non-sensical to me.
These diagrams are entirely symmetrical in terms of all dimensions, as in choice of 'left' and 'right' just as 'up' and 'down' is arbitrary

I feel there is an ambiguity in what constitutes time travel. As in, the intuition we typically may have about this being '2018-09-30' -> '2008-09-30' same place.

But in terms of general relativity, any travel with speed >c is time travel. This is called moving in a 'timelike curve' in 4D spacetime - as opposed to 'spacelike curves' which we (and all we know) typically move on. On the GIF all curves within yellow area are spacelike and blue area timelike.

So for example if you 'teleported' a light year away from your current whereabouts, that'd be considered time travel. Because if you send a light signal to earth, and teleport back - you will not see it for another year. So you influenced the future without exactly 'changing' the date on your calendar

Mind you if you simply travel half a year back/forward keeping your position fixed, you'd arrive in some different place because likely the earth, sun and entire galaxy would've moved away.
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Bart Bok - Sun, 30 Sep 2018 09:55:02 EST ID:9RKOIT3O No.57460 Ignore Report Quick Reply
or maybe better example:
  1. you travel a year back in time from now to 2017
  2. you end up a light year away from initial position
  3. 2017 you wants to send stock market results to 2018 you
  4. at best 2017 you will be able to send them with speed of light
  5. light takes a year to arrive to 2018
  6. in that case, the information you're sending arrives in 2018 and you haven't actually managed to send it back in time, because it still has to make up for the distance before it reaches you

if you change space distance from 1 light year away to 0.5 light year away however, you will be able to send information to 'past you' (with speed of light) so it arrives mid-2017 (and either you're filthy rich or paradoxically disappear hehehe)


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