>>51179503
STL

I believe the Alcubierre Warp Drive doesnt produce time dilatation.

>>51179503
>How would be an OP that considers and accepts the full consequences of grammar including punctuation and syntax violations?

But pedantic faggotry aside, it would get messy quickly, like most things with time-travel. It's the main reason most FTL methods cheat and sidestep the c limit.
Time dilation from near-c travel is much less of a headache though

Reminds me of this too: https://youtube.com/watch?v=ud6LiVJkwyA

Like anything else that uses time travel rules, I reckon.

>>51179952
>https://youtube.com/watch?v=ud6LiVJkwyA [Embed]
fukkin sweet, anon.

>>51179503
FTL would not violate causality.

It would only appear to.

Time-dilation though, is another issue.

>>51179503
>How would be a setting that considers and accepts the full consequences of FTL including time-dilation and causality violations?
Difficult. I'm not entirely sure what you mean by causality violation (the fact that you violate the law that nothing can move faster than light - one of presumed fundamental causal laws of the universe, means that that law no longer applies to your world - e.g. it's no longer a violation of it).
But with things like time dilatation, it's simply a bitch. You'd have to consistently map the world on a MASSIVE time scale, since every interstellar jump would move your settings history forward by great leaps. It would also probably means that your world would fall into many isolated systems all living at their own time with little connection to others since immediacy of contacts between them would be near zero.
The result could be good for some sort of space road trip where the players only spend limited time in each system and basically each system would feel like a world of it's own, with no possibility to go back to the one you already visited in the past - not without it changing considerably since you've been there in the past.
Again, the biggest issue would be time-scale, things like dealing with technological and political shifts.

>>51179891
>I believe the Alcubierre Warp Drive doesnt produce time dilatation.
Yeah, but Alcubierre does come with it's own issues. outside it's possible impossibility and energetic demands way outside of any comprehensible scale, the main problem with Alcubierre is space-distortion field in front of the ship would have a tendency to accumulate interstellar matter in front of the ship. Upon turning the drive off, the matter accumulated in front of the ship would expand violently, resulting in a near big-bang scenario that would most likely destroy not only your ship, but the entirety of your target destination too.

>>51179952
>>51180447
You do realize that FTL does not really propose time travel, merely time dilatation. Which means that you still move only in one direction through time - you merely "skip ahead" in it.

Alright, more important question. Is there any theoretical form of FTL travel in currently accepted physics, no matter how wacky, out there, or tenuous, that solves the problem of time dilation?

>>51181078
Alcubierre drive and Wormhole generator are the only two ones I know about. Everything else is not scientifically founded (like hyperspace drive or space-time-discontinuity abuse that I've seen used in sci-fi are really not based on any real possible physics).

Both wormholes and Alcubierre drive, if possible, would solve the issue of time dilation, as they technically speaking don't rely on anything moving at high speeds: instead, both rely on the notion of the space itself being molded around the ship.
Each have their own issue though: the biggest of which is that both require such INSANE amounts of energy that it actually just feels out of whack. To create a worm-hole, or fuel an Alcubierre drive for a reasonable amount of time, you'd probably need more energy that you'd get by anihilating all matter in our solar system with 100% efficiency.
Hell, opening a wormhole would probably require more energy than creating a reasonable sized black hole artificially.
Alcubierre on the other hand has it's own issues, as mentioned above. Even if you fueled it, and had access to exotic matter that is presumed necessary for space-dilatation required to make it run, you are still going to cause little big bangs every time you run it through interstellar space.

>>51181078
Time dilation isn't a bug, it's a feature

>>51181078

We probalby need exotic forms of matter with negative, imaginary mass, or antigravity for any form of FTL. It is easier to make an artificial, proton-sized Black holes with the help of powerful lasers (E=MCsquare) than to make a FTL machine.

>>51179503
It's an interresting question.
In real life, causality is only preserved by the fact all forms of faster than light are really impossible, even wormholes would allow you to go back in time and kill your "past" self before he uses the wormhole because there is no universal timeframe.
For example, there is time-dilution between Mars and Earth because they don't revolve around the sun at the same speed so portals linking Earth and Mars would break causality at least at particles or molecular level.
And even in deep space you are moving relatively to all other things in the universe.
The speed limit for information perfectly compensates by nature time-dilation so it gives us the illusion of a absolute time.

So yeah a realistic FTL would
A) Not being possible at all for fundamental physics reasons.
B) ALWAYS be time travel, you cannot "cheat" because sidestepping the c limit is time travel by definition and it don't matter if you move faster than light, teleport or warp space itself.

But in a sci-fi setting where FTL somehow exists yet physics is realistic at least for time dilutions would be an interresting setting where space travelers would have to deal with the fact ftl is always time travel and always breaks causality.
For example, you cannot go so much faster than light without going too much in the past (so space empires are limited in size as it puts a a maximal effective ommunication and travel speed and an interresting interaction between the core of an empire and its furthest solar systems)
Also, the universe is not a computer who would crash if a paradox occurs or a story where a paradox would be retconned by God.
If you use ftl travel to go in the past and kill your past self...nothing would happen to you.

>>51181840
All FTL space travelers would effectively* exist within their own continuum, and whether or not they can end up in a different one depend on how they travel faster than light : always if they use a wormhole or if they can teleport directly to the spatial and time frame from where they are coming from, never if they just move faster than light.
Example : If you use a wormhole to go in the past and kill your past self and then use this wormhole again, you will end up in a future where you never killed your past self.
If you use a FTL spaceship, then you will remain in a continuum where you killed your past self, everything that happened to you in the future only happened from your perspective yet you still exist.
This is also a problem for space empires because each time you send someone somewhere with FTL travel, from your persective you have to hope you "are" in the continuum where they come back as you could be in the one where they indeed have traveled to where they were supposed to go...yet they disappeared at the instant they used FTL to come back. (Altough the locals would always end up in a continuum where they come back, even if these same locals still somehow exist in the continuum where the travelers don't come back but that's because the locals from the first continuum and planetary system 1 are the source of this continuum and never the locals of the second planetary system)
(This problem don't exist when someone uses FTL travel from where you are because you are both in the same local space, but each time someone try to use FTL travel to GO where you are then they will indeed travel succesfully and be able to talk to the locals from both perspective....but not yours if you don't happen to be in the same "continuum" as there is no absolute time in the universe)

>>51181851
*This is different from a multiverse branching with each FTL travel because a multiverse implies a greater set of physical laws and a greater universe where both universes exist
...while actually the eventual "synchronization" between the two timeframes is just broken and each one cease to exist at all for the other one

>>51181213
There may be engineering solutions to that to require less energy. Even the need exotic matter could be solve with clever tricks.
.

>>51181851
You forgot about another possibility - self-maintained consistency.

It means that, basically, any actions that would lead to a paradox are impossible. If you try to go to the past and kill your past self, your FTL drive will malfunction, or your shot will miss, or you will slip on a banana peel, hit your head and die while on the way, or you will shoot an android that looks exactly like you and learn that your memories of ever being in this place in that time were artificially implanted. In any case, it's impossible for your past self to die, or the past to be changed in any way in general.

>>51181078
No.
It don't matter if we can create wormholes, warp space or whatever, moving FTL is not the problem.
We cannot avoid time dilation with any form of FTL travel so FTL travel breaks causality and by consequence is impossible.
People will say "muh muh alcubierre drive, muh muh wormholes" becausd they think moving faster than light is the problem but the true problem is the fact c limit is the way the universe deals with time dilution.

>>51181437
Then the impossibility of FTL travel is a feature.

>>51181977
Nope, what you describe is narrative logic, this is not how the universe works.
This is good for stories but FTL travel always being time travel and time travel always breaking causality is simply evidence for both FTL travel and Time travel being impossible.

File: 9009ef126844a257ae1b81e53(...).jpg (107 KB, 615x406)

107 KB JPG

>>51181977
I kinda have this rolling as a thing in my games, with the idea that the players have begun to see little mounting violations of it that are starting to leave them shitless, especially since they're pretty sure they're responsible.

Also tying into idea of quantum immortality, where there's someone who they currently have kept alive who ABSOLUTELY was meant to, supposed to, had to die in an infinity of places and times. The kind of doom where you just can't stop it from happening, just like you can't go back and kill yourself; a beyond 100% certainty across all possible existences.

Only she is alive. Further and further beyond the terminus point into a timeframe that's gathering increasing impossibility, which will, funny enough, eventually allow a man to move faster than light.

>>51182012
It's impossible if all the postulates about physics hold. Some of them were chosen empirically on no more basis than we haven't observed anything that would overturn them.

The simplest case is the postulate of all inertial reference frames being equal. If it turns out there's one, and only one, inertial reference frame in which FTL travel is possible (which would make it not equal to other IRFs), then causality violations by FTL would be impossible, since they require travel between different IRFs.

>>51182049
What I described is Novikov's self-consistency principle, which is a physical model.

>>51182026
Novikov's self-consistency principle takes care of any paradox
There, FTL is now possible

>>51180930
>>51181037
FTL in a universe with time dilation breaks causality.
Time dilation don't only happen when you are in a car or a spaceship, but EVERYWHERE and for EVERYTHING as everything is relative to everything as there is no an objective timeframe and gravity weakens with distance but its reach is infinite.
Instant teleportation to an inch from where you were would breaks causality, a wormhole on Earth linked to a wormhole on Mars would breaks causality at least because of the protons, gravitation, particles and maybe atoms or even molecules.
A wormhole on Earth linked to a wormhole on a very fast celestial body would even allow us to time travel at a macroscopic scale.

>>51182192
No, it does not and no, it would not. And I have no idea why you people consistently conflate time dilatation and time travel: you don't fucking travel through time when you travel at the speed of light: not any more than you travel through time when you WALK. You are part of the same fucking continuum, you don't end up on a different time "plane", just on a different place of that very same continuum. That is the fucking reason why the idea of time dilatation was introduced, to actually maintain consistency of space-time continuum: time dilatation is what PREVENTS you from travelling through time.
>Instant teleportation to an inch from where you were would breaks causality
No, it would really not. Also, it's not an instant teleportation: wormhole is a place you travel through, not a startrack teleporter.

>Mars would breaks causality at least because of the protons, gravitation, particles and maybe atoms or even molecules.
What the actual fuck?

>A wormhole on Earth linked to a wormhole on a very fast celestial body would even allow us to time travel at a macroscopic scale.
What you mean "fast"? Fast in what way, fast relative to what?

>>51182192
The problem I have with that is that it implies observation is the same as existence.

If you can somehow bypass the speed of light, then you are going faster than the propagation of the information of your travel.

Essentially saying that because the people where you're arriving haven't seen the video of you leaving yet, then you've violated cause & effect.

>>51179503
>full consequences of time travel
Overrated. Time is and should be wibbly-wobbly. Just have fun instead.

>>51182223
You're committing a frequent error here. Causality is violated not because you outrun the information about an event. If a reference frame is moving very fast relative to another reference frame, it's possible for events to occur in different order relative to one frame than relative to another frame. Not the information about the events, but the events themselves.

>>51182087
>>51182160
There is no a single proof the universe has this kijd of self-corrective quality.
Honestly it boils up to "Time Travel can inherently breaks causality so something like fate must exist so people can only time travel in ways preventing causality breaks"
What kind of physical forces could do this kind of stuff ? It probably would have to be quasi-intelligent.
And that's not like only macroscopic changes or actions can breaks causality.
Photons and other fast atoms, gravitionnal forces moving back and forth between two wormholes also breaks causality because of time dilation.

>>51179503
>a setting that considers and accepts the full consequences of FTL including time-dilation and causality violations?

That setting is called Orions Arm.

The related ideas are:

1. Realistic wormholes are not like classic Scifi depictions. This is important to note because as soon as you say "this setting has wormholes" people stop listening and start talking B movie Scifi.

2. Wormholes can be created and maintained.

3. The end points of a wormhole can be moved, but that movement is always STL, with time dilation consequences if moved close to light speed.

4. The effects of time dilation ought to cause causality violation between different endpoint pairs, however:

5. One, or the other, or both wormholes will collapse before they can be brought close enough together to violate causality.

>>51182381
Of course there's no proof. To prove or disprove this theory we would have to achieve time travel first.

However, saying "time travel is impossible because it could break causality" is the same as saying "humans are impossible because they could invent a time machine which could then break causality." What is impossible is breaking causality in itself.

Similarly, posing that a quasi-intelligent force is required to prevent time travel from breaking causality does not in principle differ from posing that a quasi-intelligent force is required to prevent humans from inventing time machine.

>>51182381
>Honestly it boils up to "Time Travel can inherently breaks causality so something like fate must exist so people can only time travel in ways preventing causality breaks"
You might be interested in Fermat's Principle of Least time required. If you want to know further what I mean, I wholeheartedly recommend reading Ted Chiang's "Story of Your Life" short story (the one on which the recent movie "Arrival" has been based - but read the story, don't just watch the movie).

>>51182218
Planets revolve around Stars, Stars revolve around the massive wormhole in the center of their galaxy, galaxies themselves are moving because of other galaxies,ect...

Mars and Earth don't revolve around the Sun at the same speed, so if there a wormhole on Earth, a wormhole on Mars and the two are linked and there is not preferred time frame in the universe.
If a photon can travel quicker to the other end of the wormhole through the wormhole quicker than through normal space, then by definition there is a frame of reference where the photon will exit the other end BEFORE it enters.
Which is what happen with all forms of time travel unless Einstein was wrong and there is indeed a preferred frame of reference.

Er. Whoops.

>>51182452
>Blather. In short, I should go back to bed.

The salient point being:
>full consequences of FTL

In other words, Orions Arm doesn't have FTL. Pointing this out might save an avalanche of useless discussion, since it's not what the OP is looking for.

Sorry about that.

>>51182456
Occam Razor don't proves or refutes anything but still advices against choosing an unneccesarily complicated hypothese over one with less assumpations.
Mainly because any hypothese can always be replaced with one with more assumptions.

>>51182560
Jesus. I don't even know where to begin... So first of all, Galaxies are not confirmed to revolve around wormholes. We assume existence of very large BLACK holes in the centers of SOME galaxies.
Second of all:

>a wormhole on Mars and the two are linked and there is not preferred time frame in the universe
What the ACTUAL FUCK. Look, I appreciate your enthusiasm but if you have absolutely ZERO basic physical education, maybe you should not exactly discuss this subject, or at least don't make what pretends to be informed claims. What FUCK is "preferred time frame" for fuck sake: time is space and space is time. There is no one, or multiple "time frames": if it's in space, then it's also in time - there are not multiplicities of time frames (only observers frames of REFERENCE, but that is a whole different issue).

>, then by definition there is a frame of reference where the photon will exit the other end BEFORE it enters.
No, it really does not. Traveling through wormhole IS traveling through normal space you idiot. Wormhole is not sudden different space or time: it's regular old space-time continuum that is really warped, but it's still the same fucking thing.
Frame of reference does not matter. Our perception of time is heuristic at best and largely irrelevant. If the time is bent, then it's bent, but there is no time travel and no different time planes.
It seems to me that you are somebody with barely elementary school understanding of physics actually claiming that Einstein was wrong, which is baffling to say the least.

>>51182601
I don't think Occam's razor can be applied to constructing fictional settings.

>FTL causes problems because time-travel/dilation

No, it does not. Time dilation occurs all the time in the universe due to gravity, even without the extremes (black holes). When an astronaut goes to the ISS, time flows faster for him relative to us. When you sit next to the fat kid in class, time flows slower for you relative to others. This does not break the universe, why would FTL?

If FTL is some sort of subspace bubble, it only really matters how your timeflow is inside that bubble (e.g. your seconds aren't years in the real universe).

>>51182632
Actually, except for mixing up wormholes with black holes and time frames with frames of reference, everything that anon said completely agrees with contemporary physics.

>>51182452
>>51182566
I love Orion's Arms too but yes, yes wormholes are indeed a form of time travel even if you have to move the end of a wormhole with slower than light means.
Once one end is far from enough from the other that a photon would reach more quickly the other end through the wormhole than through normal space, it becomes FTL travel and...violate causality.

>>51182658
Except those are literally the cornerstones of his statements. Frame of reference is irrelevant to physics and space-time continuity, and not understanding the difference between a wormhole and black-hole suggests not really understanding the fucking basic problem we are talking about.

>>51181019
>possible impossibility

We have observed the physical distortion of space by a large mass, LIGO announced that back in February last year, so the physics behind it is probably valid. Scale is still a major problem, though, since it took the equivalent of 60 solar masses for us to notice. Best case scenario, the effect diminishes with distance like most infinite-range physics effects, but that still only bumps the energy requirements down from "utterly absurd" to just "absurd".

>>51182658
Thanks, anon, I'm sorry if I got the vocabulary wrong but in what am I mixing up wormholes with black holes ?

>>51182740
Not him, but for starters: wormholes are hypothetical and have never been observed, while blackholes are well observed and reasonably well studied phenomena: each having entirely different physical properties.
Black Hole is just an object of unusually large mass: large enough to bend light passing it in certain distance to always travel into it's center: which is where the name "black hole" comes from.
Worm-hole is a hypothetical (unobserved) physical body that bends spece-time so hard that it can actually connect two very distance places.

On a side-note:
I think most people in this thread confuse causality with medium which we generally use to observe causality (that is light). Causality does not occur at the speed of light, and FTL does not break causality: It's just that most causal relationships we know and observed are physical particle interactions: and of course, light being the fastest physical particle-like-thing we know about, most of causality we observed happened (at max) at the speed of light.

However, we know about multiple phenomena that are causal but happen instanteniously, at speeds FASTER than light. The light-speed limit is really just a matter of physical particles. Things like superpositions within particles seem to happen faster than that. The gravity propagation and gravity waves we recently discovered to be real apparently too seem to happen faster than light propagates too.

>>51182740
A black hole is what is believed to be in the center of our Galaxy, not a wormhole.

>>51182704
>Frame of reference is irrelevant to physics and space-time continuity
Anon, you're literally doing the same thing yourself. Does it suggest not really understanding the fucking basic problem we are talking about?

>>51182817
>Anon, you're literally doing the same thing yourself.
Unless you are planning on to go about some stupid tirade about utterly misunderstood concepts of quantum physics and the problem of observer which really does not mean what you think it means: no. I'm not wrong on this. Our observation of certain extremely limited and largely heuristic idea of conditions that surround us and the universal physical rules really don't have much to do with each other. Our frame of reference does not actually constitute some kind of separate individual "plane of time". It may be difficult to imagine for us that time behaves dynamically, that it's a property of space rather than an entire set of states of being, but that still does not fucking change anything: I'm right and our immediate frames of reference are irrelevant to actual problems of space-time continutity.

>>51179503
Just make it 12 Monkeys rules, where you can't change the past because all time travel that ever bappened is already a part of the past. Much easier to keep track of than Back to the Future rules, or Star Trek rules (where there's no rules.)

>>51182797
Well...I was always talking about wormholes ?

>c limit and light
I know most people specifically think nothing is faster light when actually the true speed limit is the one of information and light just happens to travel at maximum speed in a vaccuum (an no forms of information travel more quickly than light in a vacuum) but I don't think superpositionned particles can be used to transmit information faster than light in a vaccuum / speed limit and gravity waves have a lot of potential for astronomy because they also travel as fast in vacuum that light but are not stopped or not stopped as much as photons ?

>>51182947
by matter.

>>51182811
Damn, sorry it really was a typo.
I wanted to write black hole, so sorry.

>>51182883
http://physics.stackexchange.com/questions/128075/how-would-wormhole-based-ftl-violate-causality
Is he wrong ?

>>51183048
If 'he' is the author of the question, then there's answers explaining how exactly he's wrong just below it.

>>51182947
>but I don't think superpositionned particles can be used to transmit information faster than light in a vaccuum
https://en.wikipedia.org/wiki/Quantum_entanglement
http://www.physicsoftheuniverse.com/topics_quantum_superposition.html
https://www.quora.com/Is-the-quantum-entanglement-effect-faster-than-the-speed-of-light
https://en.wikipedia.org/wiki/EPR_paradox
http://www.livescience.com/27920-quantum-action-faster-than-light.html

The predominant assumption (and the math supports it) is that quantum entanglement assures interactions between subparticle states happening instanteniously or at least at speeds VASTLY exceeding the speed of light. The problem is merely that it's difficult to test, because the speed of light is going to define the speed at which we observe it.

>>51183048
I'm gonna have to read it carefully, but I can already say that the QUESTION is already wrong.
>the clock on board our hypothetical FTL spaceship would tick backwards to some outside observers
Already shows that this is some profound and fundamental misunderstanding of what the fuck are we talking about. There is no "outside observer" unless you assume a hypothetical being OUTSIDE OF TIME AND FUCKING SPACE. If the "outside observer" would not be travelling alongside the ship at same speed, he would not be able to observe the clock to begin with: if he had been at the same or similar speed, then he would experience "regular" time dilatation".

>>51183073
>>51183093
The answer.

>>51183093
>If the "outside observer" would not be travelling alongside the ship at same speed, he would not be able to observe the clock to begin with

I'm sorry, what?

>>51183124
The answers are correct as far as I can tell

>>51183127
>I'm sorry, what?
How do you observe something at a unobservable speed? We cannot observe something that moves (relatively to us) at speed greater than light, because observation itself is dependent on our ability to observe particle-like objects, which can't move faster than light.

>>51183143
Except for him basing his answer on an extremely simplified version Minkkowski diagram from 1908, you mean?

>>51183093
I dunno, I'm a bit dubious as from my understanding information traveling in anyway faster than c is a big, fundamental no in physics and I have about quantic superposition not counting as a form of information.

>>51183198
What is the good answer ? I'm pretty sure you were the guy saying that wormholes don't violate causality.

>>51183241
>from my understanding information traveling in anyway faster than c is a big, fundamental no in physics and I have about quantic superposition not counting as a form of information.
Your understanding is wrong, plain and simple. The only thing we know, the only thing that Einstein postulate, is that no particle can move at speed exceeding speed of light in vacuum. It never said anything about information, or about possiblities regarding quantum physics, mostly because one was irrelevant to him and the other was not yet really discovered.

>>51183354
>I'm pretty sure you were the guy saying that wormholes don't violate causality.
If wormholes exist (which we do not know for sure), they don't violate causality. Actually, the idea of violation of causality is silly. Causality is possibility in different name: if it exists, then it's causally possible and consistent: if it's causally inconsistent, then it does not exist, plain and simple. Our current understanding of causality might change, but that means we just got the particular causal line wrong, not that causality itself has been violated.

The good answer here is that it's all purely theoretical, but we do not have any evidence that would actually make wormholes impossible, and even have theoretical grounds on which they might be, at certain conditions, necessary. Meanwhile, a lot of half-educated people will use this subject to wank off their theories in order to prove intellectual dominance, and will use any tools they can get their hands off (like, in this case, Minkowski diagram, which I really had not seen being used as a relevant argument in physics in decades (after all, the Mikowski diagram in that particular post PREDATES EINSTEN'S GENERAL THEORY OF RELATIVITY BY SEVEN FUCKING YEARS!) to prove whatever personal theory they fancy. So I would definitely not put much of my faith into this particular post.

File: carmen miranda's ghost.jpg (20 KB, 480x360)

20 KB JPG

>>51179952
Patrician Tastes my friend.

https://www.youtube.com/watch?v=lDv8_gKSosU&index=2&list=PLaP6jbqNUfjCbqmuJyXql2nCxbaVTWrzx

>>51181019
>Upon turning the drive off, the matter accumulated in front of the ship would expand violently, resulting in a near big-bang scenario that would most likely destroy not only your ship, but the entirety of your target destination too.

That's not the issue as I've understood it. Wikipedia states that:

>"Brendan McMonigal, Geraint F. Lewis, and Philip O'Byrne have argued that when an Alcubierre-driven ship decelerates from superluminal speed, the particles that its bubble has gathered in transit would be released in energetic outbursts akin to a sonic boom shockwave; in the case of forward-facing particles, energetic enough to destroy anything at the destination directly in front of the ship."

If that's what you are thinking about, we only really need to angle the ship correctly on arrival. Ultimately, should the Alcubierre Drive otherwise work, it might be possible to create "warp gates" for laning, where everything in front is kept clear, and where routes went through areas with as low density as possible.

>>51183462
Thanks for the explanations, but in the case wormholes exist,
What would prevent two ends of an wormhole to be temporally espaced enough (or with enough time dilation) that someone could enter one end and then come back BEFORE his "past-self" entered the wormhole ?

And what's the deal with people saying we couldn't use quantum effects to send messages faster than light otherwise we could receive the answer be we send the message ?

>>51183615
*before sending the message.

>>51183615
>What would prevent two ends of an wormhole to be temporally espaced enough (or with enough time dilation) that someone could enter one end and then come back BEFORE his "past-self" entered the wormhole ?

I'm not sure what you mean by "espaced", but what you suggest is impossible. Time passes equally on both places. They're not separate. It is no difference than you successfully stepping off a platform and onto a train moving at full speed, because for all intents and purposes, the worm-hole is the bridge between them, no matter where the two exit points are or how they move in relation to eachother.

>And what's the deal with people saying we couldn't use quantum effects to send messages faster than light otherwise we could receive the answer be we send the message ?
No idea. It's nonsense.

>>51183615
>What would prevent two ends of an wormhole to be temporally espaced enough (or with enough time dilation) that someone could enter one end and then come back BEFORE his "past-self" entered the wormhole ?
No, because there is no "before". We percieve time as a cascade of events one after another, but that is not really how it works. Time is, again, more like property of space. You would not enter it "before" you exist it, you would just find yourself at a different place of space-time continuum.
If you used a hypothetical worm-hole on earth, connecting two places one AU away from each other, then immediately turned around and shined a flashlight into it, then closed the hole and shined another flashlight (strong enough to be detected back on earth): the first flash would pass through the wormhole with the time necessary to traverse the hole itself (which will be less than a second AFTER you entered), the other flash will arrive to earth exactly one year after you entered it.
It's impossible for the flash to arrive at earth before you enter it, because at the absolute minimum, it will travel there with the speed of light. There are two possible paths: through the wormhole (which is short) or outside the worm-hole which is going to be always EXACTLY EQUAL TO THE TIME LIGHT NEEDS TO COVER DISTANCE BETWEEN EARTH AND THE SPOT WHERE YOU WERE WHEN YOU FLASHED IT. Both will take time, none of them will arrive earlier.

>>51183615
>And what's the deal with people saying we couldn't use quantum effects to send messages faster than light otherwise we could receive the answer be we send the message ?
Again nonsense based on misunderstanding of time. It's not "different time" at different places: time is the same at all places. It behaves differently based on your relative speed and the space-time curvature, but the time is the same, nothing is "ahead" of anything, it's just that your perception of it within that time will differ from the perception of a person in a different type of dilatation.

You don't travel through time when you travel at speed of light: you just percieve time slower.

>>51183757
You're oversimplifying. To travel into the past, you'd need to travel by wormhole to a frame of reference moving at a considerable fraction of c relative to your starting frame, and then travel back through another wormhole.

>>51183673
>>51183757
>>51183784
Thanks, and would physical FTL travel (Somehow moving faster than light in vacuum, maybe several order of magnitude fasters) involves time travel and/or causes problems with causality or not at all ?

>>51181019
>It would also probably means that your world would fall into many isolated systems all living at their own time with little connection to others since immediacy of contacts between them would be near zero.
>The result could be good for some sort of space road trip where the players only spend limited time in each system and basically each system would feel like a world of it's own, with no possibility to go back to the one you already visited in the past - not without it changing considerably since you've been there in the past.
I read a novel with a setting like this, but I can't remember the name.

>>51183844
Interresting one, is it an evidence for wormholes not being possible ?
If wormholes exist, what would prevent such a scenario to be possible ?

>>51183844
No, that would lead you to just arrriving shortly after you fucking left. A wormhole with a "frame of reference" (you mean wormhole in region where time is more dilated, ergo. a person in that place would experience it as happening slower than the person back on earth) would at absolute best result in you coming back very shortly after you left, while experiencing more time passing at the target destination than at Earth.
But that is NOT TRAVELING BACK IN TIME. That is just experiencing time passing slower for a while than others, then going back. You can't come out of the wormhole, no matter what, BEFORE YOU ENTER IT.
The same would happen if you just entered a region with unusually high gravity for fuck sake, you don't even need wormholes to experience time dilatation.
There are no actual discontinutities: you experience time going at a different rate. Fuck, you experience time going at a different rate than on earth surface if you and orbit the moon already. That is not time travel either.

>>51183889
It's not an interesting one, it's wrong. And no, we have no evidence of wormholes being impossible. Such a scenario would prevent the mere fact that it's not how wormholes and time works.

So anons as non physicist I ask for explanation:
If I make a jump to X from Earth and back how could I arrive before I jumped in the first place?

I jumped at earth time Y, and arrived at earth time Y
On X time flows different than on earth but time on earth moves forward by it's own pace. I need some time to make a jump back. So no matter how fast time moves on X I should always by back by earth time Y+Z. Where Z is time I needed to make a jump. Of course Z would wary between planets, but I can't image it would be negative.
Also I'd outrun information transmitted by light about my travel, but why would I give a fuck about it?

>>51183914
You do know, anon, that the order of events relative to different frames of reference can change, if the relative speed is high enough? If you can jump between these frames you WILL travel in time.

>>51182192
Exactly. At least one of the following must be true:
1. FTL Travel (yes, including communication. Yes including whatever clever way you're imagining to get around the rules) is impossible.
2. There actually IS a privileged reference frame, and all physics since Newton is rubbish.
3. There's no such thing as causality.

>>51183943
A lot of it is rubbish.

Dark Matter and Dark Energy for example are pretty much entirely made up to balance out the equations that were being found to not work in the simulations.

>>51183943
>all physics since Newton is rubbish.
That's too strong. After all, Newtonian physics is still relevant today despite being, strictly saying, wrong. The same would happen to Einsteinian physics.

>>51182797
I may not be understanding what you're saying; I hope I am. I haven't taken physics since college, though so my knowledge is spotty anyway.

Gravity is instantaneous?

>>51182560
>then by definition there is a frame of reference where the photon will exit the other end BEFORE it enters.

Thats like saying that any dude with a hammer can time travel, because if you hit something with a hammer and make a loud noise, someone standing far away will see the hammer fall before they hear the sound OH MY GOD THESE ARE OUT OF SYNCH THE UNIVERSE IS BROKEN SOMEONE HELP CAUSALITY WAS A MYTH ALL ALONG.

>>51183198
>We cannot observe something that moves (relatively to us) at speed greater than light, because observation itself is dependent on our ability to observe particle-like objects, which can't move faster than light.

Not that guy, but question about that: if I'm moving at half c and you approach and pass me at c, does this mean that I will be able to observe parts of your page?

>>51183964
Newtonian physics are more imprecise than wrong, and are simpler to use for a lot of applications than modern physics with some "fixed" values to compensate the innacuracies. (even if we couldn't know what they would be with newtonian physics alone)

>>51184077
>Image of the event : slower than light in vacuum.
>Sound of the vent : slower than light in vaccum, slower than light in air
????

>>51184033
>Gravity is instantaneous?
That is... highly debated. At the moment, the math actually suggests that yes, it is. The problem is that it cannot be confirmed, because our tools allow us to observe only gravitational WAVE, which we do know to move at the speed of light. Here is the fucking problem:
99% of all empirical observations of large gravity distortion phenomena we can observe are observed THROUGH GRAVITY LENSING. We don't "see" gravity, we see how it bends light that we watch. Or in general, how it affects other particles and matter in general around.
Since we assume that gravitation is a property of space itself (specifically curvature of space), it makes absolutely zero sense to assume that it propagates in the same way as particles do, unless we are missing something (like some kind of profound space-time particle thing, but we have no evidence of such thing).
We know that, as Einstein said: there are "really spooky actions that interact instantly over great distances", including gravity, electromagnetic fields and later on, quantum entanglement.

Recently, we had a whole BUNCH of articles saying that the "speed of gravity has been confirmed to be the same as speed of light", but it's just an absolute misinterpretation of the real data: what we really discovered was that gravity can produce "wave" like effect (sort of ripples in lensing), and we observe those - unsurprisingly, to move at the speed of light. Because: we OBSERVE THEM IN LIGHT.

Gravity itself is more difficult, but again: we have no reason to assume that particles somehow throttle all interaction speed in universe, especially since quantum theory is tarting to prove the opposite.

>>51184033

Maybe not instant, but apparently faster than light.

Basically, the important thing to remember is that MATTER cannot exceed the speed of light, because at the speed of light it becomes energy, and energy just moves at light speed. Light speed is the speed that light moves at, so that is just what it is.

But things that are not matter do not (necessarily) have this limitation. Space itself is a fluid, and we have reason to believe that space can move faster than light. The universe itself, for example, seems to be expanding faster than light.

Gravity effects (or simply just is as a fundamental level) curves in spacetime. So if (somehow) a massive new source of gravity was to appear, the effects of that gravity would be transmitted not by particle physics but by spacetime physics. Local spacetime would be affected faster than the speed of light.

This is the 'loophole' that things like the Star Trek warp drive use to zip around the galaxy. The ship itself isn't going fast, they simply 'warp' a bubble of space time into moving ITSELF faster than the speed of light while everything inside the bubble still obeys the conventional laws of physics. The Albicurre drive is based around the same principal, but it unfortunately requires exotic matter and levels of energy that we have no idea how to achieve (if they can be done at all).

>>51184152
>>51184178
Is a gravity wave, well, a wave?

If you make two next to each other will they have interference? If it's not really physically there was that only be observable if it were directly affecting light or matter?

>>51184307
>Is a gravity wave, well, a wave?
Precisely.
>If you make two next to each other will they have interference?
Precisely.
>If it's not really physically there was that only be observable if it were directly affecting light or matter?
Not sure if I understand.

>>51184338
The analogy I'm using in my head is explosions, because of the shockwaves.

If you detonate two explosives close enough together, the shockwaves will hit each other with extra force. That's moving matter, though, and gravity is not matter.
So if you had two gravity waves converge I'm assuming the would be effects because of the waves interacting, but I'm guessing you would need to have light and/or matter in the way to be able to observe the effects. Which also could imply that there are no known effects in the absence of matter?

>>51181019

> Upon turning the drive off, the matter accumulated in front of the ship would expand violently, resulting in a near big-bang scenario that would most likely destroy not only your ship, but the entirety of your target destination too.

Hmm.

What if there were a system to use the energy from that?

If we are talking sci-fi, you could use it as a reason why space travel is relatively frequent. The energy required to start the engine is huge but when you stop you get back some of the energy.

>>51183927
I'll try to illustrate how time travel with wormholes would work.

First of all, and most important, you need to accept that in the universe where time dilation and length contraction occurs according to Special Relativity, the order of events is relative to the observer's frame of reference.
I'll illustrate it with a well-known paradox of barn and ladder. Suppose you have a barn with a front and a back door, and a long ladder that moves through this barn at a significant fraction of the speed of light. Let the lengths of the ladder and the barn be equal when they're at rest.

In the frame of the barn, the ladder is moving fast enough to contract - let's say it becomes twice shorter. This means that when the rear end of the ladder passes the front doors of the barn, the front end of the ladder is somewhere inside the barn. When the front end of the ladder passes the back doors of the barn, the rear end has *already passed* the front doors.

In the frame of the ladder, on the other hand, it's the barn that is moving very fast and experiencing length contraction. In this frame, the barn is twice shorter than the ladder, and the front end of the ladder passes the back doors *before* the rear end passes the front doors.

>Cont.

>>51184556
Now imagine we have a wormhole with one end in at the back doors of the barn and the other end at the front end of the ladder. Suppose you stand in the barn's frame and jump into the wormhole in the precise moment the front end of the ladder reaches the back door. From your POV the rear end of the ladder is in the middle of the barn at this moment. You find yourself on the ladder, the ladder's front end is at the back doors, but the ladder's back end is outside the barn even though it was inside just a moment ago.

Now, that's not everything. Once the back end of the ladder reaches the front door (you've calculated the time of this based on the barn's speed relative to you, so no signal delay is involved), you jump back into the wormhole, and voila - you're back in the barn while the front end of the ladder is still in the middle of it. In other words, you've travelled to the past.

>>51184536
>What if there were a system to use the energy from that?
From my understanding, it's like trying to contain the energy of a several million nukes going of simultaneously, it's not exactly easy to handle. I mean it seems to me that it would be easier to just contain and harvest energy of an entire Sun.
That said, yeah. It's not going to pay equal, but most of the energy is shit you yourself supplied into the system to begin with, so you'd get a small return of the investment (presumably in volumes of percent or less), which is still better than not getting back anything and accidentally blowing up your destination too.

>>51184656

If the ship were decelerate at a reasonable speed, the energy output should be manageable. I mean if the ship has batteries to store several solar masses, it shouldn't be unreasonable to contain the mass from several nukes.

>>51184656
If you're forcing several matter on a scale of multiple solar systems into a single point, won't you potentially be making a black hole where you arrive?

>>51184689
>If the ship were decelerate at a reasonable speed, the energy output should be manageable.
The problem is that alcubierre drive is not so much about acceleration. It's about reaching a critical point of your energy output to start bending space in front of you. I'm not sure gradual lowering of the energy output would result in gradual release.

Also, not several nukes. Billions of nukes. It's a little Big Bang: you are basically forcing the particles to act and maintain highest possible energy order, similar to the conditions at the very first moments of the presumed thermal expansion of Big Band.
But then again: the amount of energy you would need to invest to make Alcubierre drive working in the first place is going to be even orders of magnitude larger, so... it's all really entirely theoretical.
Honestly, it's hardly imaginable that we could get an Alcubierre drive running (purely by the energy requirements) without confirming AND having access to vacuum energy, which would probably make energy a non-issue entirely. I guess.

>>51184690
>won't you potentially be making a black hole where you arrive?
The theories I've heard do not actually assume the matter would collapse, merely that it would temprarily reach extremely high energy state. The assumption is that you actually only collect interstellar dust and particles, not entire systems because... wow, that would be nasty. I guess you COULD cause a black hole (In theory, at least) if you flew through a solar system with an alcubierre drive, but really... I don't know.

The assumption is that you DON'T plot your course through an entire solar system, merely that you'll gather a lot of small dust and interstellear particles along your way through otherwise "empty" stretches of the universe.

>>51184761
>The assumption is that you DON'T plot your course through an entire solar system, merely that you'll gather a lot of small dust and interstellear particles along your way through otherwise "empty" stretches of the universe.

Suppose you did, and made a big bang within the big bang.... Assuming you survived, that would stretch the expanding new part of the universe in front of you faster than you could travel through it, and give you an odd frame of reference for interacting with it, yes?

>>51184152
I'm afraid you're wrong and the scientific community is right. Gravity is not istantaneous.

>>51185186
Not really. Mostly because what I'm saying is in agreement with the scientific community. It's actually merely popularization of science that got the news wrong, which happens at virtually every single major scientific discovery over the past few decades.

>>51185186
What about me ?
Was I right ?

>>51185214
>http://math.ucr.edu/home/baez/physics/Relativity/GR/grav_speed.html

>>51185303
Are you retarded, or just too lazy to read properly before jumping into discussions to antagonize people?
Go back, read what I posted - properly this time- , maybe read the fucking article you yourself linked, and then we can actually have a discussion. Until then, fuck off.

wait. didn't LIGO prove that gravity moves at the speed of light?

>>51185330

>>51184152
>it makes absolutely zero sense to assume that it propagates in the same way as particles do
>>source
>In general relativity, on the other hand, gravity propagates at the speed of light; that is, the motion of a massive object creates a distortion in the curvature of spacetime that moves outward at light speed.

>>51185350
It proved that gravitational waves move at the speed of light. How exactly we can observe waves in it when it travels instantaneously is something I'd love to hear the answer to from the gentleman and scholar >>51184152

>>51185385
Not him, but I believe that gravity and gravity waves are separate things. Gravity waves are space-time moving in fun ways under certain circumstances; gravity itself is an instantaneous property

>>51185370
I asked you something you idiot. I specifcicaly separated the effect that gravity has on particles (that is gravitational wave) from gravity itself. JUST LIKE THE FUCKING ARTICLE YOU LINKED DID. Gravity DOES. NOT. MOVE. YOU IDIOT.
PARTICLES AFFECTED BY GRAVITY DO. AND THAT IS HOW WE OBSERVE THE IMPACT OF GRAVITATIONAL FIELD CHANGE: BY OBSERVING THE PARTICLES IT AFFECTS.
AND OF COURSE, NO FUCKING SURPRISE THERE, THOSE PROPAGATE AT MAXIMUM AT SPEED OF LIGHT.

Jesus, I basically fucking quoted the article you linked you god-damn moron.

>>51185385
>>51185418
Just kidding. As per the easily googled Wikipedia article, gravity waves are absolutely a different thing. They're a specific phenomenon that occurs under set circumstances.

>>51185435
c, faster than c, and instantaneous are all conjecture, right? Because we don't present have a way to measure the distance?

Also, thought experiment: if two objects are moving away from each other and both are moving at three quarters of c, relative to each other one is moving at 1.5 c, right? If either object were able to put off a gravitational wave, would that be a situation where you could measure the speed of gravity?

>>51185435
But gravitons do move at c, Mr. Van Flandern

>>51185435
Do you have any evidence that gravity propagates faster than light?

>>51182192
>Time dilation don't only happen when you are in a car or a spaceship, but EVERYWHERE and for EVERYTHING
In the same sense that a shrink ray is functionally a universe enlarger, yes. In practical terms, no.

And if there were a clock placed at the moment of the Big Bang that runs forever with perfect accuracy and 0 absolute velocity (impossible, I know), there is no manner in which you could ever see it read an earlier time than you had already, short of using some sort of hyper-telescope to view it from extremely far away and then traveling faster than the speed of light to it. Even then, you couldn't observe an earlier time than the first observed time minus light delay, even with instantaneous transit.

New idea; a race of sapients decide that they want FTL travel, but don't want time travel or time dilation because of the problems it has with building a proper space empire.

Through some glorious moment of serendipity that would reduce the walls of their physics to rubble, they discover how to generate and maintain local absolute reference frames. Within the region of space-time affected by their ARFs, FTL travel is possible as you would want it to; you simply go faster than light with no problems.

The ARF itself propagates faster than light, and can be mounted on a superluminal vehicle.

What consequences does this have for the rest of the universe?

The aliens themselves don't actually know how it works, only that it does somehow and that they can build them, and that any ship with one that travels a hundred light years out in a day, and then comes back in a day, has only aged two days.

>>51179503
boring as fuck

things like that always end up as dumb experiments instead of something that can support a story

>>51185554
>relative to each other one is moving at 1.5 c, right?
No. Speed of light is the same in all reference frames. Despite what you might expect, they move at the speed of 0.8c relative from each other.
http://www.physicscentral.com/experiment/askaphysicist/physics-answer.cfm?uid=20130130105151
https://www.quora.com/If-the-relative-velocity-of-two-particles-moving-with-speed-of-light-opposite-to-each-other-is-calculated-will-it-be-2c

>>51185739
Am I dealing with a twelve years old here? How many times do I have to fucking tell you to read what I said, for fuck sake.

>>51184690
I think an attempt would be made to not pass directly through star systems. Probably making trips in 2-3 legs in order to travel mostly outside of the plane of the ecliptic. That said, depending on how large the area of distorted space is, it would be pretty fucking hard to pick up multiple star systems in any straight-line shot. Space is fucking big, and there's not really a whole lot of anything in it.

>>51185907
>How many times do I have to fucking tell you to read what I said, for fuck sake.
I read what you said, and it just that the math seems to support, and that space-time doesn't operate by conventional matter principles, but you haven't actually given an actual explanation or evidence that gravity propagates faster than light.

File: 18SFP23_Flash-Gordon-Rock(...).jpg (19 KB, 501x342)

19 KB JPG

>>51179503
>considers and accepts the full consequences of FTL
wormholes use wormholes
you are not going faster than light you just bring pont a and b closer to each other by warping space time temporarily
in all likelihood that will really be how humans go to the stars
or leaving our spacetime all together by going to a parallel dimension and re entering it at a point of your choosing

Thread seen on Suptg.

"OP asks about the consequences of realistic FTL travels to /tg/ towards causality and time-dilution, 51181840 Anon nails it."

>>51180930
Wrong.

>>51185435
>IF I TYPE IN ALL CAPS THAT MEANS I AM RIGHT AND YOU ARE WRONG

>>51183505
Reading all this on the Alcubierre drive's destructive power upon exiting FTL just made me realize that it'd make for an incredibly powerful weapon.

>>51179503
It's sublight travel that produces time dilation. Causality is generally time travel's thing.

What, exactly, are you on about?

>>51183757
technically an AU is about 8 light minutes, not 1 lightyear. (just nitpicking)