/sci/ - Science & Math

According to special relativity, it means there exists a frame in which two events, one being the cause of the other from your point of view, will shift in order.

You can't have causality with FTL.

Since we have causality, that means no FTL.

I seriously hope you're not so poorly educated to believe in ftl?

Just a stupid thought of mine, but causality breaks the symmetry of spacetime. Could there be the symmetry isn't broken under some conditions?

>>5082684

Nope.

FTL is just as impossible as an engine that makes no noise or heat.

No.

People say that relativity implies that FTL travel implies time travel, however relativity is actually inconsistent with FTL travel, so it can't imply anything about it.

FTL travel would disprove relativity and violate lorentz invariance, demonstrating a preferred frame of reference.

It is often claimed that a preferred frame of reference has been disproven, however, only various individual methods of detecting the preferred frame of reference have been disproven. We have failed to find evidence of a preferred frame of reference, but this does not mean we have found evidence against a preferred frame of reference, only against a frame of reference that is preferred in certain ways.

>>5082695
That is an absolutely terrible comparison.

Engines can be made which suck noise and heat out of their environment, which produce negative noise and heat. Obviously they can also produce net zero noise and heat.

Your example isn't any better than saying, "FTL is just as impossible as a cow flying through the air." as if you had never heard of a cattlepult.

>>5082671
General Relativity does not imply causality. If you choose to believe in causality, that's you're business but it's not science

>>5082708

>Engines can be made which suck noise and heat out of their environment

But they create heat in doing so.

I'm saying that you cannot make an engine that produces work from energy without a percentage of that energy being lost to heat.

You'd have to be completely ignorant of thermodynamics to argue otherwise.

Cattlepult? Are you trying to be unfunny or are you just stupid?

Question: If you travel backwards at the speed of light do you go FORWARDS in time?

>>5082742
>I'm saying that you cannot make an engine that produces work from energy without a percentage of that energy being lost to heat.
You have to increase entropy, you don't have to increase thermal energy. There are actions which absorb thermal energy, lowering temperature, while increasing entropy.

Consider doing work with compressed carbon dioxide. Since it cools as it expands, you can design an engine such that no part grows warmer as it does work.

Your understanding of thermodynamics is childlike in its naivety.

Actually, being able to travel faster than light destroys the entire idea of causality. So asking if you're going "forwards" or "backwards" becomes meaningless--it could seem either way depending on what perspective you take.

>>5082698
This guy also makes a good point. FTL travel is possible if relativity is wrong. But relativity is only wrong if the laws of physics don't apply universally in all inertial frames of reference. That's a pretty important assumption that we hold about the universe though, and is not to be tossed aside lightly.

>>5082760
>That's a pretty important assumption that we hold about the universe though, and is not to be tossed aside lightly.
Considering its importance, the fact that it's only an assumption shouldn't be tossed aside lightly.

http://news.discovery.com/space/warp-drive-possible-nasa-tests-100yss-120917.html

>>5082773
>implying everything in science isn't an assumption

>>5082791

>http://www.doxa.ws/other/Miracles.html

>>5082757
>Consider doing work with compressed carbon dioxide. Since it cools as it expands, you can design an engine such that no part grows warmer as it does work.

If you don't count the compressor and it's power source as part of the system, yeah.

But that's cheating.

>>5082791
>http://news.discovery.com/space/warp-drive-possible-nasa-tests-100yss-120917.html

Is there any actual study linked there? All i see is shitty science journalism with nothing but other bombastic links.

Is there anything more to this than one guy who works (worked?) at the JPL saying "he thinks" it's possible?

Because this seems about as tenuous as christians citing people surviving disasters as miracles.

>>5082796
We prefer "no preferred frame of reference" over "a preferred frame of reference which has thus far managed to remain undetectable under our intense scrutiny" on the principle of occam's razor.

It is wise to keep this in mind: the only reason we have to keep the principle of relativity in our fundamental model is that it simplifies the model. If we find ourselves in such a position that discarding it and accepting a preferred frame of reference results in a cleaner, simpler, or more complete theory, then we would be irrational not to do so.

There are some people who abuse occam's razor so badly that it is a wonder when they use a real one that they don't shave off their noses.

>>5082801
>>5082814
Pink and orange, respectively.

retard here, WHY ftl violates causality and all that jazzity jazz?
Does anyone really knows or you parroting like retards

>>5082808
>If you don't count the compressor and it's power source as part of the system, yeah.
When you analyse the thermodynamics of a coal-powered steam engine, do you include the wood burned to cook the meals of the men who constructed the engine, the sun shining on the leaves of the plants that became the coal, the supernovas that released the iron, carbon, and oxygen involved in the engine, and the big bang that produced the hydrogen?

>>5082840

>*petulant crying*

I'm sorry, did i hurt your feelings by pointing out that a part of a machine is part of a thermodynamic system?

>>5082832

Did you get that off reddit?

What, you can't argue without someone else's bullshit pyramid to assist you?

>>5082834

Relativity proves that FTL travel is identical to Time travel (to help your research, the technical term for time travel is "Closed timelike curve"). Time travel makes Causality impossible, since it can be used to create paradoxes. So if you have Relativity and FTL, Causality is impossible. If you do not have Relativity, FTL is not Time travel, so you can have Causality. Or more mundanely you can have Relativity and Causality, but no FTL/Time travel (the latter is the opinion of physicist Stephen Hawking, he calls it the chronology protection conjecture).

>>5082846
A compressor and power source isn't "part of the machine" in an engine that runs on compressed carbon dioxide.

Seriously, you have no point to make here. Your understanding of thermodynamics is garbage.

>>5082843
I got it from here 2 years ago.

And I'm not arguing, same as you.

>>5082857

So in your hypothetical model that i assume also contains a perfectly spherical cow, contains an unlimited source of compressed carbon dioxide?

Well then i guess refrigerators don't make heat either. After all, that part on the back isn't part of the machine.

>>5082857

>this just in, fusion reactors are perpetual energy machines! they generate more power than they take in, since the external source that starts it isn't a part of the machine!

Brilliant.

Causality, relativity, FTL: pick any two.

That said, the Everett interpretation of quantum mechanics (at least) strongly implies macroscale causality.

>>5082850
Many people tried to explain this to me, this made alot of sense.
At least for the part that you explain that paradoxes violate causality, easy to understand.
What i don't understand is how would ftl would be time travel.
Many things can be considered as time travel, if you approach a black hole or go really fast time slows down.
I thought it was called relativity, which gives you the sense that weird time mess is ok, since its relative.
So something that goes faster than light shouldn't cause problem to causality, just like high gravity that messes with time.

I hope you understand my confusion.

>>5082871
First of all, it's only an existence proof of an engine that does work without heating anything.

>So in your hypothetical model that i assume also contains a perfectly spherical cow, contains an unlimited source of compressed carbon dioxide?
My model contains a completed engine with its fuel loaded, you complete idiot.

Just as when you analyse the operation of a coal-powered steam engine, you don't worry about where the coal came from, or how hard it was to build the engine. There's no special exemption for "naturally-occurring" fuels.

The radiator on a fridge is obviously part of the machine. The coal mine, battery factory, or CO2 compressor is not part of the machine that consumes the coal, electrical power, or CO2 cylinders, any more than the big bang is.

>>5082874
This is possibly the most stupid post I've seen on /sci/ all day.

Worst greentext strawman ever.

>>5082642
No. Anyone who says otherwise is an idealist who has renounced s simple pragmatic understanding of physics and reality.

>>5082907

and you're saying that these mystical CO2 engines have no loss of energy to friction? at all?

Well well. so sorry for doubting you and you vast engineering ignorance.

>>5082905

Well your major problem is that you're trying to understand a complex mathematical framework with words alone.

Take a GR course. analogy can only take you so far.

>>5082920
Don't you get tired of being stupid?

I never said there were no friction losses. I said that it was possible for no part of the machine to increase in temperature as it operates. It can be constructed so that friction only happens in the same spaces as contact with expanding CO2.

An entire closed system can do work while decreasing in temperature everywhere and increasing in temperature nowhere. This does not mean entropy isn't increasing. Entropy and enthalpy are not the same thing.

>>5082937

> never said there were no friction losses. I said that it was possible for no part of the machine to increase in temperature as it operates

>friction

>doesn't create heat

>the energy it takes from the machine is just destroyed

Kids these days...

mlz

>>5082976
>>the energy it takes from the machine is just destroyed
The energy it takes into the machine goes into the expansion of the CO2 rather than into an increase of temperature.

Tell me: what is being heated in a compressed-CO2 rocket operating in a vacuum?

It's an engine. It does work: the rocket is accelerated through space. Every part of it is cooled as it operates.

How is this not an "engine which makes no heat"?

warp bubble

>>5082905
First you must understand time dilation. In a nutshell: Maxwell's equations of electromagnetism predict that light goes at c regardless of your frame of reference. If two observers moving relative to each other both see light going at c, something weird is going on (consider a car driving along at .5c with its headlights on. An observer in the car sees the light speed out of the headlights at c. An observer on the road as the car speeds by *also* sees the light moving at c, not 1.5c). Each observer must measure time and space differently.
In the end, it turns out that you can predict the difference between the clocks of two reference frames solely by their relative speed using remarkably basic trigonometry. As you approach the speed of light, your clock seems to slow down and stop from an outsider's perspective. After you pass the speed of light (which you cannot do thanks to a similar scaling-up of the energy required to accelerate), you begin to appear to move backward in time to an outsider.

That took a while to type; I hope you're still in the thread.

>>5082999

uh, the rocket nozzle as each and every molecule of CO2 hits it on its way out? just because the CO2 radiates this heat does not mean that heat was not created.

>>5082999

How does friction produce workable energy when friction is the conversion of energy to heat?

>>5083021
>uh, the rocket nozzle as each and every molecule of CO2 hits it on its way out?
You think an initially warm rocket nozzle is going to be heated by contact with progressively colder CO2 gas?

You fail at thermodynamics AND rockets.

>>5083003
http://en.wikipedia.org/wiki/Alcubierre_drive

>>5083031

So you're saying that F=MA no longer applies and that no force or energy will be imparted on the rocket nozzle because the molecules are cold?

Fuck man, you can keep shitposting all you like, but you're not going to make sense.

>>5083035
Have fun with multiple valid realities.

>>5083042
>So you're saying that F=MA no longer applies and that no force or energy will be imparted on the rocket nozzle because the molecules are cold?
Oh my fucking god. You can't actually be this stupid.

The "force or energy" that "will be imparted on the rocket nozzle" accelerates the rocket. In any rocket, this cools the propellant. In a rocket with a cold propellant and warm nozzle, it also cools the nozzle. Within a certain range of relative temperatures, it does both at the same time so neither increases temperature at any time.

A rocket nozzle is a device for converting thermal energy into well-ordered kinetic energy in the form of directional movement.

>>5083048

why exactly would we have multiple realities? using this method, the vesel itself is stationary and never breaks C. clock tick rates stay relatively the same.

not trying to be an asshole, im actually interested in where you are coming from. all the current math states that causality wont be violated... could the math be wrong? absolutely, but it rarely is.

Supposing that one could move at the speed of light, but it won't break causality i.e. no time travel, what would it look like to an observer? Would it look like a black or flickering mass? Would the image look refracted? Would photons accelerate?

>>5082642

sci-fi thread. not /sci/

delete this thread OP

1. You're not going to see something moving at the speed of light.

2. Only moving FASTER than the speed of light (apparently maybe) result in time reversal.

>>5082738
>traveling backwards
>same as going forward in a different direction
>implying any direction you take makes a difference

>people still thinking direct FTL is possible.

>>5082642

time travel is possible just as FTL, but the energy requirement is steep.

look instead at wormholes and portals, as being researched at sandia labs.

What a puerile discussion.

>>5082642
Indeed it does. Although tachyons are permitted in SR, they are unphysical as they are not in the Wigner classification of the Poincare group. Also, when the Virasoro algebra is extended to allow particle states to transform as spacetime spinors that can be both bosonic and fermionic, the tachyons are eliminated from any possible physical theory. This is an extraordinary implication of supersymmetry.

>>5082684 but causality breaks the symmetry of spacetime
No, it does not. This is crackpot nonsense. All physically-realized spacetimes are equipped with time orientation and causal structure. CTCs result in inherit vacuum instability.

>>5082698
>however relativity is actually inconsistent with FTL travel
The correct wording would be to say all of physics above the 17th century is incompatible with FTL travel.

>It is often claimed that a preferred frame of reference has been disproven, however
More mindless pseudointellectual drivel. Please demonstrate to me one mathematically consistent physical model which reproduces standard model predictions and includes a preferred frame. You cannot have a symmetry group in which the speed of light is constant in every frame of reference and simultaneously allow for FTL travel in all/some frames. Crackpot "proposal of concepts" are meaningless in the scientific community.

>>5082695 >>5082708 >>5082742 >>5082757 >>5082808 >>5082840 >>5082846 >>5082857 >>5082871 >>5082874 >>5082907
All of your infinitely infantile childish analogies fail as they have no relationship with SR.

What a puerile discussion.
>>5082642
Indeed it does. Although tachyons are permitted in SR, they are unphysical as they are not in the Wigner classification of the Poincare group. Also, when the Virasoro algebra is extended to allow particle states to transform as spacetime spinors that can be both bosonic and fermionic, the tachyons are eliminated from any possible physical theory. This is an extraordinary implication of supersymmetry.

>>5082684 but causality breaks the symmetry of spacetime
No, it does not. This is crackpot nonsense. All physically-realized spacetimes are equipped with time orientation and causal structure. CTCs result in inherit vacuum instability.

>>5082698
>however relativity is actually inconsistent with FTL travel
The correct wording would be to say all of physics above the 17th century is incompatible with FTL travel.

>It is often claimed that a preferred frame of reference has been disproven, however
More mindless pseudointellectual drivel. Please demonstrate to me one mathematically consistent physical model which reproduces standard model predictions and includes a preferred frame. You cannot have a symmetry group in which the speed of light is constant in every frame of reference and simultaneously allow for FTL travel in all/some frames. Crackpot "proposal of concepts" are meaningless in the scientific community.

>>5082695 >>5082708 >>5082742 >>5082757 >>5082808 >>5082840 >>5082846 >>5082857 >>5082871 >>5082874 >>5082907
All of your infinitely infantile childish analogies fail as they have no relationship with SR.

>>5082735
Why do you insist on spewing populist pseudoscience? Please provide me with a stable solution to the EFEs that does not admit causal structure.

>>5082760
He does not make a "good point", he spews crackpot populist pseudointellectual garbage, and the principle of relativity is not an *assumption*; it is a rigorously experimentally proven statement in which all of modern physics is irreproducible without.

>>5082773 >>5082825
Here's what you sound like right now:

"I don't really like relativity because it makes the measurement of time and space problematic; in particular, time fails to be centrally organized. Again, the everyday experience suggests a simpler way of thinking: there must be a preferred frame, right? The laws of physics should allow some really ambitious conclusions such as wormholes, time that is running backwards, communication with parallel worlds or the deity, or anything else that can be described in the media as a sensation that every single ordinary person can understand!"

What would the implications of a preferred frame be besides blatant incompatibility with all existing known laws of physics and all existing known experiments? Please entertain me with more unbelievably stupid experimentally invalidated mediocre philosophy.

>>5088365
>infinitely infantile childish analogies
Impressive vocabulary.

>>5082670
First post contains the correct answer, no need to read the rest of this shitty thread.

>>5082850
You have not a clue what you're talking about and are spewing silly laymen populist pseudoscientific trash. CTCs are not the same thing as time travel. A CTC is a non-constant timelike (future-directed) curve starting and ending at some point <span class="math">x[/spoiler]. Tachyons do not necessarily follow CTCs. Regardless of this both of these are impossible.

>>5082904
You seem to be forgetting that this "interpretation" is astoundingly fraudulent anti-scientific junk which can be disproven in roughly 40 seconds with remedial QM involving projection operators. Is that really so hard to understand that the wave function in quantum mechanics is a generalization of a probability distribution - and not a generalization of a classical field? It encodes the information about the physical system, not the shape of the object itself. It is not really difficult to learn these things but some people just don't want to.

>>5082905
There exists only three solutions to the metric on a Lorentzian manifold <span class="math">M[/spoiler] for any tangent vector <span class="math">v\in T_x M[/spoiler] to a curve <span class="math">\gamma:\mathbb{R}\to M[/spoiler]:
timelike <span class="math">g(v,v)<0[/spoiler]
lightlike <span class="math">g(v,v)=0[/spoiler]
spacelike <span class="math">g(v,v)>0[/spoiler]

>>5087822
No, it is not. Time travel is unphysical. FTL is unphysical. The Alcubierre metric assumes a blatant negative energy source. This is not possible.

>>5088365
Oh my god, you are such a crackpot pseudoscientist!

I suppose you only come to /sci/ to find a place where you can intimidate people with references to advanced mathematics most of the people you're talking to simply haven't heard of.

Must be a nice break from losing every argument in school.

FTL travel or communication would not imply time travel, and is not "unphysical". It would imply a preferred frame of reference. We only treat the principle of relativity as fundamental because experiments thus far have failed to show evidence of a preferred frame of reference. An FTL signal is just one of many as-yet-unobserved phenomena that would falsify lorentz invariance.

Science doesn't work by declaring principles preferred due to occam's razor as unquestionable axioms. If you ever get into a position where you're doing so, what you're doing is no longer science.

>>5088380
>What would the implications of a preferred frame be besides blatant incompatibility with all existing known laws of physics and all existing known experiments?
This is why people see you as loonshit crazy instead of respecting you.

A preferred frame wouldn't need to have "blatant incompatibility" with "all existing known experiments". It would be a big surprise. We've had surprises like that in the past, which couldn't be predicted from past experiments and weren't consistent with the theory at the time. The way we responded to them was changing the theory. That's why we have such useful and productive theory now.

You've got a very basically unscientific way of thinking about this stuff.

>>5088402
>Oh my god, you are such a crackpot pseudoscientist!
Typical pathetic response from a pseudointellectual crackpot who got proven wrong. ;)

>with references to advanced mathematics
Physics is written using the language of symmetry groups. If you do not understand mathematics, you have a popsci laymen understanding of physics. This is not advanced at all btw, I haven't touched anything over undegraduate physics so that just continues to show your pseudointellectual understanding of the material. ;)

>FTL travel or communication would not imply time travel
As I've already stated, there exists only three solutions to the metric: timelike, lightlike, or spacelike. Please explain to me what you think otherwise.

>Must be a nice break from losing every argument in school.
I actually come here and go to many other places as I find it interesting to argue with crackpots such as yourself. Are you Zephir, by any chance?

>It would imply a preferred frame of reference.
Please explain more. How so? Also, please define "preferred frame" so I know what the hell you're talking about.

>We only treat the principle of relativity as fundamental because experiments thus far have failed to show evidence of a preferred frame of reference.
All known laws of physics do not allow for a preferred frame of reference. A trivial example is classical electromagnetism in which the speed of light remains constant in every frame of reference. A preferred frame cannot reproduce this.

http://en.wikipedia.org/wiki/Michelson-Morley_experiment
http://en.wikipedia.org/wiki/Length_contraction#History
http://www.amazon.com/Spacetime-Physics-Edwin-F-Taylor/dp/0716723271

>>5088432
>Science doesn't work by declaring principles preferred due to occam's razor as unquestionable axioms. If you ever get into a position where you're doing so, what you're doing is no longer science.
I don't think you know what science is. All science requires assumptions. It is the reproduciblity of experiments and predictability which is important. Explain to me how a preferred frame reproduces existing laws of physics.

>>5088418
Oh wow, this is hilarious.

You just made a claim.
>A preferred frame wouldn't need to have "blatant incompatibility" with "all existing known experiments".

Please explain to me how to get classical electrodynamics from a preferred frame. Any reference will do. I've already told you there exists no isometry group which can reproduce translational/rotational invariance, hold the speed of light in every frame, and simultaneously allow for FTL travel.

If you cannot do this you are making absolutely baseless claims.

>This is why people see you as loonshit crazy instead of respecting you.
Nobody sees me as "loonshit crazy" with exception to the crackpots such as yourself. Lorentz invariance holds all the way up to Planck length. - http://iopscience.iop.org/0034-4885/73/7/074901

FTL does not necessarily imply time travel, there are ways around this. The most elegant is to assume a preferred frame of reference. Note that this does not mean that relativity goes out the window, but it is an EXTENSION slapped on top of relativity. All our experiments to date would still be valid, and the universe would be actually described by relativity EXCEPT for the FTL effect itself.

CMB would be the most natural choice for such a preferred frame.

http://www.physicsguy.com/ftl/html/FTL_part4.html#chap:unsolvableparadoxes

>>5088444

Sheldon?

>>5088451
>FTL does not necessarily imply time travel
Clearly you do not realize that Lorentz invariance is the only game in town.

>there are ways around this.
No.

>The most elegant is to assume a preferred frame of reference.
Except this does not reproduce known laws of physics.

> Note that this does not mean that relativity goes out the window, but it is an EXTENSION slapped on top of relativity.
As I've already stated,
> there exists no isometry group which can reproduce translational/rotational invariance, hold the speed of light in every frame, and simultaneously allow for FTL travel.
And you are a crackpot.

>CMB would be the most natural choice for such a preferred frame.
You are confirmed for not knowing the definition of "preferred frame". There clearly is a frame where the CMB is at rest, sure. But for doing any physics experiment, any other frame is as good as this one. So the only difference is that in the CMB rest frame you measure no velocity with respect to the CMB photons, but that does not imply any fundamental difference in the laws of physics. The CMB as your inertial frame implies the complete opposite to your FTL claims, you still have Lorentz invariance. And here's your experimental evidence for this: http://en.wikipedia.org/wiki/Cosmic_microwave_background#Primary_anisotropy

>http://www.physicsguy.com/ftl/html/FTL_part4.html#chap:unsolvableparadoxes
Some random crackpot website? No even a *.edu domain? I'm not even going to bother looking at the author, nonetheless the title. How about you provide an actual source such as a published paper or something on hep-th?

>>5088434
>Explain to me how a preferred frame reproduces existing laws of physics.
Are you completely stupid? It wouldn't have to "reproduce existing laws of physics" it would only have to approximately agree with their predictions in special cases, the same way relativistic and quantum mechanics do with classical mechanics.

Your objection to new theories is that they are not identical to old theories. That's not a standard consistent with genuine scientific thinking.

>>5088493

>Some random crackpot website?

He has a PhD in particle physics, and if you dont believe him, here is another physicist claiming a similar thing:

http://www.science20.com/alpha_meme/faster_light_neutrinos_do_not_time_travel_spoil_your_date-83029

Now how about you actually read and address their arguments?

>>5088549
You have to understand where he's coming from: in his mind, 90% of guys with physics PhDs are crackpots, including everyone who doesn't like string theory and considers lorentz invariance falsifiable rather than axiomatic.

>>5088555
Well, you'd better bring some pretty serious big guns before anyone takes you serious if you're trying to mess with Lorentz invariance.

>>5088540
Back on the planet where I live, you again fail to understand how physics works.

I don't care what you formulate. Give me something with a preferred frame that can calculate say the self-energy of an electron. You are sidetracking the argument.

>Your objection to new theories is that they are not identical to old theories. That's not a standard consistent with genuine scientific thinking.
>it would only have to approximately agree with their predictions in special cases
That's hilarious. SR reproduces classical mechanics with a limit from the Poincare group -> the Galilean group. Same equations, no difference.

Quantum mechanics reproduces the exact laws of classical dynamics with an hbar -> 0 limit. Same equations, no difference.

General relativity reproduces Newtonian gravity with a weak field limit. Same equations, no difference.

You are a crackpot.

>>5088549
I'm afraid that your IQ has descended below the level of a simian with its frontal lobes removed. I told you I want a published paper or hep-th article, not some random blog. I can create one on science20 right now and post crackpot garbage. It does not justify anything.

The FTL neutrino result has been thoroughly disproven and shown to be a loose cable - http://agenda.infn.it/getFile.py/access?resId=2&materialId=slides&confId=4896

>>5088578

>Give me something with a preferred frame that can calculate say the self-energy of an electron.

You dont need to travel FTL (use the preffered frame) to do that. It would be identical to current relativity. You only invoke the preffered frame when dealing with FTL travel.

>>5088555
>90% of guys with physics PhDs are crackpots
More like 5-10%. They are just a very active bunch ;-)

>including everyone who doesn't like string theory
There is nothing wrong with string theory. What do you not like about string theory?

>and considers lorentz invariance falsifiable rather than axiomatic.
The evidence for Lorentz invariance is experimentally overwhelming. You cannot reproduce known laws of physics without it. I guess the IOP paper was too much for your crackpot brain to handle - http://physicsworld.com/cws/article/news/2009/oct/28/special-relativity-passes-key-test

>>5088593
Yes you do. Calculating the self-energy of an electron requires spacetime translations for the propagator, and spacetime rotations for the spin. These must be modified to support a preferred frame.

>>5088606

If all FTL travelers/etc are required to take on a specific frame of reference when they begin their FTL trip, then there will be no way an unsolvable paradox can be produced. This is because it takes two different FTL trips from two DIFFERENT frames of reference to produce the paradox. Under this provision, if you are sending tachyons, the tachyons must only travel FTL in the special frame of reference. If you are folding space, the folding must be done in the special frame of reference. If you are using the special field itself to allow FTL travel, then you must take on the field's frame of reference. Etc. If these are the cases, then there will be no way to produce an unsolvable paradox using any of the FTL concepts.

We should realize that it does seem to directly contradict the idea of relativity because one particular frame of reference is given a special place in the universe. However, we are talking about FTL travel, and many FTL concepts "get around" relativity just to allow the FTL travel in the first place. *Further, the special frame doesn't necessarily have to apply to any physics we know about today.* All the physics we have today could still be completely relativistic. In our example, it is a special field that actually has a special place in the physics of FTL travel, and that field just happens to have some particular frame of reference. Thus, the special frame does not have to be "embedded" in the makeup of the universe, but it can be connected to something else which just happens to make that frame "special" for the specific purpose of FTL travel.

You can interpret it that way, but it somewhat acts as a mechanism that prevents accelerating mass faster then the speed of light.

I'd ignore all that and concentrate on "warp" drives.

>>5088432

>;)

you had my respect and there you lost it

>>5088606
Dude, this is a failure of your imagination, not a cogent argument.

Nobody's saying that lorentz invariance will be disproven within the limits of current observation and tested prediction.

The principle of relativity looks like it holds for frames of reference stationary to a location on Earth's surface, until you get some pretty sensitive instruments. But once you build yourself a big-ass free-rotating pendulum, long-range artillery, or good-quality gyroscope, you have to admit that you can detect some accelerations happening, that you have to account for in calculations beyond a certain precision.

However, for a lot of the stuff we do, we just don't bother making these corrections. Because treating a location on Earth as a frame of reference still allows very good precision for a lot of applications. It's possible to do a lot of experiments that prove to quite impressive precision that the principle of relativity holds in Earth-location-stationary frames, and become very convinced that this is a fundamental, inviolable principle.

Especially if you refuse to even listen to someone pointing out that these experiments don't quite cover *every* possible violation of the invariance of Earth-location-stationary frames.

>>5088641
What does this gibberish have to do with anything? I asked you to give me the spacetime isometries for the FTL theory. It doesn't matter if it has to effect a non-FTL frame, as I've already stated. Tell me how to transform coordinates in the preferred frame.

If you can't give me this, your concept is again a "crackpot proposal".

>>5088706
>Show me how your theory which violates lorentz invariance in special cases obeys lorentz invariance in all cases.
Insane demand is insane.

I can't believe you're unable to see the problem with this reasoning.

>>5088677
>Dude, this is a failure of your imagination, not a cogent argument.
I asked you or the other imbecile to explain to me how to translate coordinates in an FTL frame. Your incoherent rambling has nothing to do with this discussion.

I already know what he is going to give me (and a few variants thereof), and I just cannot wait to show him how regardless of how he rewords his unfalsifiable nonsense, it is not compatible with the standard model. Preferred frames do not work, and saying that they might means nothing. The scientific method you learn in 1st grade requires you design a model which is compatible with existing empirical evidence while simultaneously allowing for predictability. I should be able to input some quantities and get empirically-measured data.

>>5088730
I did not say anything about Lorentz invariance. I asked you to tell me how to do coordinate transformations in a preferred frame.

>>5088724
Your whole attitude toward this is wrong and stupid.

Inability to formulate a complete alternative theory in full detail on the spot with the full predictive power of all current mainstream physical theory is not equivalent to being unable to make a meaningful comment on the potential for alternative theories having certain features and agreeing with the experimental record being possible to formulate, you idiot savant.

>>5088736
>I asked you to tell me how to do coordinate transformations in a preferred frame.
The question is completely insane. You don't do coordinate transformations in a preferred frame. You do coordinate transformations between equivalent frames.

>>5088749
I asked you how to do a coordinate transformation in a preferred frame. I used to teach an undergraduate mechanics course where this would be a 1 point homework question out of a 50 point assignment on SR. Any undergraduate could do this in 60 seconds.

Like I told you already, I assure you that if you find another "qualitatively new" solution that matches your simple criteria of preferred frame + speed of light constant in every frame, and it will be a real working one, not just a crackpot "proposal of a concept", you will become very famous among hep-th physicists. It is pointless arguing with someone who doesn't even know what they are talking about, but I guess that's what you get when university education in cesspools like the US is so pricey.

I'd love to continue with this high level of discussion, but kindergarden break time appears to be up, so you must have to go.

>>5088760
I don't think you know what a coordinate transformation is. I'd love to explain to you what map coordinates are and how <span class="math">x^\mu \to x^\mu + a^\mu[/spoiler] comes out in SR, but I'm sure there are more useful things you could be doing, like lying down on the freeway.

>>5088785
Seriously, you have no fucking clue. You fail at an extremely basic level of reasoning.

Take any sort of relativistic theory you like. Pick a frame at random. Say, "I prefer this frame. This frame is preferred by me."

Does anything stop working? Anywhere, at all? No. It doesn't matter that you personally prefer one frame of reference. Everything else can keep working the same way.

Now we add a phenomenon, that has not previously been observed. It allows only something which is stationary in the preferred frame of reference to teleport instantly to another location which is also stationary in the preferred frame of reference. This breaks all sorts of principles we previously believed, but only changes predictions when the phenomenon is involved, and it's something that happens only certain extreme conditions currently outside of our experimental record.

Whenever this phenomenon is not involved, does anything stop working? Anywhere, at all? No. It doesn't matter that this new pheonomenon prefers one frame of reference. Everything not involving the pheonomenon can keep working the same way.

We currently have no clear motivation for a theory with a preferred reference frame. That's why we only talk about the set of such possible theories as potentialities. There's no point whatsover in going into detail about one possibility selected at random.

>>5082670
This. Nothing less than this and nothing more than this.

>>5082671
>You can't have causality with FTL.

FTL may be entirely impossible, and so this claim may be untestable. It is possible, however, that the Novikov self-consistency conjecture is correct, and if so, provides an avenue for causality and FTL/time travel to exist in the same universe without causing paradoxes.

This is not to say I believe FTL is in any way likely, only that one need not disregard the possibility of FTL of the basis that it must violate causality. There are a host of other, better reasons to disregard the possibility of FTL.

>>5088838
You are the definition of an aggressive brainwashed crackpot demagogue. Your preferred frame garbage effectively returns us before 1905. The Lorentz symmetry has been safely known to hold since 1905 when relativity was written down, and hypotheses that picked a privileged reference frame for light - because of their prediction of aether or FTL nonsense - have been falsified for more than 100 years, since the Morley-Michelson experiments. Some people don't want their misconceptions to "ever" be falsified, but the violations of the Lorentz symmetry have also been falsified by Fermi, even at the Planck scale, which is really the last point where it makes any sense to doubt the Lorentz symmetry.

And one should mention that Einstein's principle of relativity - the equivalence between different inertial systems - was really nothing new in 1905. It was just a "neutrally" stated principle of relativity that has existed in the Galilean form in classical mechanics. There is no preferred frame of reference in the Galilean group. That was an important part of science for more than three centuries. Sorry to say but it's time for all people who are not classifiable as idiots to finally take notice. The relevant observations to this are that on the Earth's surface, we don't even detect that the Earth is moving 30 km/s in the solar system, by other speeds around its axis. In the moving train, we can't detect that we're in a moving train as long as the motion is uniform, etc. This is known from informal as well as very accurate observations and is summarized as the principle of relativity, a cornerstone of physics: physical laws have the same form if we add the velocity <span class="math">v[/spoiler]. The equivalence between the inertial frames, together with the constancy of the speed of light, implies the Lorentz symmetry of the laws of physics, as Einstein showed in 1905. No preferred frame can reproduce this.

And the Lorentz symmetry implies a photon of energy E1 is fully equivalent, by a Lorentz boost, to any other photon of any energy E2. There can't be any restrictions on the allowed energy of a photon. For any relativistic Doppler shift factor "K", there exists a velocity "v" that generates this factor "K". Preferred frames cannot reproduce these effects. These are experimentally verified formulae which astronomers depend on daily.

Your comment that you can randomly pick a frame and make it privileged while maintaining the laws of physics elsewhere contains the same stupidity as the statement that you can randomly change the laws of physics to suit your needs for any scenario without having a consistent group of transformations valid everywhere. Pretty much defeats the purpose of science. You may as well opt for other mathematically inconsistent, untestable, “not even wrong” (dare I use this crackpot’s vocabulary), philosophical nonsense such as young Earth creationism, some lunatic claiming he is able to turn water into wine, and a variable speed of light. They are all equivalent to this breathtakingly dishonest anti-scientific subhuman activist garbage.

I think you have some several intellectual limitations that prevent you from understanding what Lorentz invariance is or what invalidates it, anyhow:

>You fail at an extremely basic level of reasoning.
You fail at extremely basic high school physics. Relativity implies that empty space cannot possess a preferred frame. The purpose of the Morley-Michelson experiment was to detect the motion of a lab relative to some preferred frame. I don’t care how you modify the laws of physics in the preferred frame; you should always be able to move relative to it. The hypothesis that this infantile crackpot garbage exists without a fundamental speed limit implies the speed of light should change to <span class="math">c-v[/spoiler] and <span class="math">c+v[/spoiler] if we move relative to the preferred frame by the same speed <span class="math">v[/spoiler] in the direction of light or against it by simple coordinate transformations, respectively. I don't know how many times I need to repeat this to get it through your crackpot skull. Shouldn't it be high school physics knowledge that such things were ruled out 107 years ago?

>Take any sort of relativistic theory you like. Pick a frame at random. Say, "I prefer this frame. This frame is preferred by me."
There you go again parroting the same illogical pseudoscientific gibberish. But, sure! That totally kills the invariant <span class="math">\Delta \tau = \sqrt{dt^2-c^{-2}(dx^2+dy^2+dz^2)}[/spoiler], disregards the Morley-Michelson experiment and countless other tests of special relativity but let's go on!

Let's assume for the sake of argument there *IS* some isometry group which maintains c in all frames while allowing for FTL travel in one. We'll call it the crackpot group. Any boost regardless of the frame in the crackpot group makes velocity nonzero, the rotational symmetry would be broken in all other laws in all other frames, goodbye angular momentum, and goodbye Lorentz invariance.

So what does this mean?

In http://arxiv.org/abs/hep-th/0603158 we see a preferred frame with a hypothetical crackpot group violates the second law of thermodynamics.

We see in http://arxiv.org/pdf/0706.2179.pdf that with any kind of preferred frame the dispersion relations over spacetime with the crackpot group depends on infinitely many coefficients. Looks like we can't do anything from simple classical electrodynamics to QFT now.

In general relativity, the Lorentz symmetry is really incorporated into the local diffeomorphism symmetry which is a local symmetry of general relativity responsible for both the structure of spacetime and the decoupling of ghosts (negative-norm states). The crackpot group will explicitly break diffeomorphism symmetry, so say goodbye to the gravitational field, gauge theories, and the entire standard model. - http://relativity.livingreviews.org/open?pubNo=lrr-2005-5&amp;page=articlesu4.html

And, most importantly: http://arxiv.org/ftp/arxiv/papers/0908/0908.1832.pdf - the symmetry properties resulting from a smooth, continuous, Lorentz-invariant spacetime have to hold up to distances that are 100 times shorter than the Planck length. Your preferred frame cannot exist over the spacetime manifold. This deliciously clean result means that all the theories that fail to respect the exact Lorentz invariance at the Planck scale, and that generate first-order corrections instead of it (breaking of translational/rotational/O(1) invariance) are dead. Quantum field theory allows for photons or any other free particle to fluctuate into any other particle species. The spectrum of the gamma ray burst precisely follows a universal spectral curve expected from the internal dynamics of the contributions from higher order processes in QED - ignoring all theoretical problems and mathematical inconsistencies I’ve already mentioned this means that if a preferred frame existed the probability that the photon just coincidentally did not manage to get inertial with respect to it by fluctuation during its journey or fluctuate into an FTL particle is 17 parts per billion which is de facto zero. The casualties of this discovery include all crackpot proposals in fundamental physics except for string theory and effective, exactly Lorentz-invariant quantum field theories.

>That's why we only talk about the set of such possible theories as potentialities.
Except your crackpot garbage doesn't work with existing physics and experiment. It's been known since Maxwell that light has the same properties in each point of vacuum, and as one can figure out by analyzing Maxwell’s equations, it also has the same properties in all inertial reference frames. There is no privileged frame.

Still waiting on a single published paper or hep-th article which agrees with your completely illogical claims.

>>5090001
>hypotheses that picked a privileged reference frame for light - because of their prediction of aether or FTL nonsense - have been falsified for more than 100 years
>a privileged reference frame for light
>for light
>Morley-Michelson experiments
Haven't you noticed that we're not talking about a preferred reference frame for light? Are you actually this stupid that you haven't clued in to the fact that nobody once has said anything to suggest that light's speed is constant in only one observational frame?

Do you seriously think any of these facts you're stating are new or surprising to me, or in any way conflicting with anything I've said?

Are you completely incapable of imagining that a reference frame can be preferred for some other phenomenon? Or that a reference frame can be preferred in some more subtle, hard-to-detect fashion than would show up in the Morley-Michelson experiments?

I've never even argued that there IS a preferred reference frame. Only that it's unreasonable and unscientific to treat "no preferred reference frame" as axiomatic rather than merely preferred based on occam's razor.

I'm sorry, but you are just so fucking dumb. It's pathetic how hard you work at convincing yourself otherwise, how incredibly transparent it is that you go around building these elaborate strawman positions for you to imagine that you are defeating with clear, intelligent arguments.

Damn, fundie told that nigger.

>>5090072
Are you really that stupid to think that a preferred frame without a fundamental limit on the speed of massless particles does not imply variability in the speed of light with respect to that frame?

Are you 12?

Have you even taken high school physics?

Do you even know what a coordinate transformation is?

>>5090072
>Only that it's unreasonable and unscientific to treat "no preferred reference frame" as axiomatic rather than merely preferred based on occam's razor.
I've provided you with roughly 20 facts on why a preferred frame cannot be incorporated into standard model physics.

>I'm sorry, but you are just so fucking dumb. It's pathetic how hard you work at convincing yourself otherwise, how incredibly transparent it is that you go around building these elaborate strawman positions for you to imagine that you are defeating with clear, intelligent arguments.
Strawman positions? You fail at physics bro, sorry! You haven't the slightest clue what you're talking about. If you don't take my word, go to any universities physics department and have them laugh at you!

>>5090038
>waiting on a single published paper
Whenever anyone references a published paper that supports a view you disagree with, you immediately dismiss it as written by a crackpot. And nevermind that he's a physics professor or full-time researcher at a respected institution.

You demonstrate by the way you argue that there's no possibility you'd change your position no matter what anyone said to you. It's obviously not worth the effort to try.

>>5090087
>I've provided you with roughly 20 facts on why a preferred frame cannot be incorporated into standard model physics.
You've demonstrated roughly 20 unreasonable assumptions about what "preferred frame" means.

>>5090088
>Whenever anyone references a published paper that supports a view you disagree with, you immediately dismiss it as written by a crackpot. And nevermind that he's a physics professor or full-time researcher at a respected institution.
Give me a paper. I promise you I will not say it's crackpottery.

> And nevermind that he's a physics professor or full-time researcher at a respected institution.
You are disagreeing with experimentally-verified theory and continue to sprout baseless claims while I support all of my with facts, evidence, and logic.

>>5090093
Define preferred frame. I'm using this definition, which is standard across hep-th.
>In theoretical physics, a preferred or privileged frame is usually a special hypothetical frame of reference in which the laws of physics might appear to be identifiably different (simpler) from those in other frames.

sorry for posting but I love reading the posts about this stuff, please carry on :)

>>5090099
>You are disagreeing with experimentally-verified theory and continue to sprout baseless claims while I support all of my with facts, evidence, and logic.
You are arguing against an imaginary position which nobody has expressed and rejecting all attempts to explain how you've misunderstood it, so you can go on beating on your strawman.

>>5090105
>>5090105
You made a claim.
> It is often claimed that a preferred frame of reference has been disproven, however, only various individual methods of detecting the preferred frame of reference have been disproven. We have failed to find evidence of a preferred frame of reference, but this does not mean we have found evidence against a preferred frame of reference, only against a frame of reference that is preferred in certain ways.
I told you explicitly that ANY preferred frame dramatically violates basic observations of the real world. The Fermi satellite has verified that even at the Planck scale, the Lorentz symmetry works much better than up to O(100%) errors.

>>5090101
>>In theoretical physics, a preferred or privileged frame is usually a special hypothetical frame of reference in which the laws of physics might appear to be identifiably different (simpler) from those in other frames.
That's fine.

If that's the definition you've actually been reasoning from, and you really think that just that has those implications you've claimed, then the problem isn't one of communication, but just of exceptional stupidity.

I mean, a little earlier you seriously tried to argue that the Morley-Michelson experiments ruled out the entire CONCEPT of preferred frames.

Look at this shit:
>>5090034
>In http://arxiv.org/abs/hep-th/0603158 we see a preferred frame with a hypothetical crackpot group violates the second law of thermodynamics.
When I go to the actual paper, I see that the supposed violation of the second law of thermodynamics is based on how a whole raft of assumptions interact with a purely fucking theoretical model of black hole evaporation that is totally unsupported by observation or experiment.

You're just going completely apeshit generalizing from that.

You obviously don't understand this shit at all. You just pick something that sounds as if it should be relevant, and support your position, and you throw it out there and pretend that it's proof. And you throw out so much shit, that nobody could possibly shoot it all down before you dig up some more. So even if someone does make a point against you (which might take hours of study and argument), you dismiss it as one meaningless little mistake, and still go away thinking you were totally right anyway.

>>5090126
I believe you are the one who possess the exceptional stupidity.

>I mean, a little earlier you seriously tried to argue that the Morley-Michelson experiments ruled out the entire CONCEPT of preferred frames.
Explain to me how if we move relative to the preferred frame this does not result in the speed of light changing. Provide me with a substitution to this: http://en.wikipedia.org/wiki/Velocity-addition_formula#Special_theory_of_relativity

>I see that the supposed violation of the second law of thermodynamics is based on how a whole raft of assumptions interact with a purely fucking theoretical model of black hole evaporation that is totally unsupported by observation or experiment.
Black hole entropy is not at all theoretical, you pathetic child. You have an IQ equivalent to that of a retarded monkey for being stuck in 17th century cosmology, apparently - http://math.ucr.edu/home/baez/physics/Relativity/BlackHoles/info_loss.html

>You're just going completely apeshit generalizing from that.
What is your physics education? I am not at all generalizing from this. This is one example out of many I listed. My main argument to your inane claims is data collected from Fermilab. See this post >>5090038

You are both retarded.

I can't wait for them to release time travel to regular people. I would love to see the future.

Is Carl still IQ Fundie? How does he know physics?

>>5082642
Special relativity + FTL implies:
- go back in time machine
- a preferred reference frame
- or even weirder things about reference frames

>>5090561

you cannot travel to the future because time cannot bend forward, only backwards like a moibus strip.

if moibus strip had two loops yes you could use the front facing one to go to the future.

thats why the movie seemed more believalbe when marty when to his dads school.