FTL Communication Re:/g/

[Anonymous No.5547136]

So i was told from /g/ to post this here:
Basically if Space can expand/contract faster than the speed of light, why can't we use that as a means of faster-than-light communication?

[Anonymous No.5547147]

It does not and no.

[Anonymous No.5547150]

>>5547147
Please explain

[Anonymous No.5547162]

>>5547147
...wow, i guess you don't have anything to explain.

[Anonymous No.5547170]

>>5547150
>>5547162

My answer will be in the form of a question: where is the proof that space expands or contracts at all? Without this there is no OP's question.

[Anonymous No.5547202]

>>5547170
Well...first there is wikipedia: http://en.wikipedia.org/wiki/Alcubierre_drive
Then there is the Big Bang wiki:
http://en.wikipedia.org/wiki/Big_Bang
Then this: http://news.nationalpost.com/2012/11/29/nasa-is-actually-working-on-a-faster-than-light-warp-drive-but-it-might-blow-up-any-planet-it-travels-to/
This:http://www.space.com/17628-warp-drive-possible-interstellar-spaceflight.html
And Finally This: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015936_2011016932.pdf

[Anonymous No.5547233]

Whatever effect you have on space's behavior is limited to propagating though space at the speed of light.

[Anonymous No.5547241]

>>5547233
How about you at least read this at first: http://en.wikipedia.org/wiki/Alcubierre_drive and then start being a troll.

[Anonymous No.5547248]

>>5547241
Trolling? That article should point out what I just told you, if it's a good article.

[Anonymous No.5547253]

>>5547233

This in some ways must be false, gravity as a field is created through the propagation of virtual graviton particles. If it were the case that any effect on space was sub luminally restricted these gravitons would never be able to escape the infinite well of a black hole. Thus black holes would be unable to exist.

[Anonymous No.5547256]

>>5547248


Why are you so sure you are correct in your POV if you did not even read any evidence that i have given you that says otherwise?

[Anonymous No.5547259]

>>5547248
And what do you know? It does. Look at the "Placement of Matter" section under "Difficulties."

[Anonymous No.5547268]

>>5547256
You're asking about what the theory says. That's just a matter of understanding the theory. There are no experimental implementations of warp drives.

[Anonymous No.5547272]

>>5547253
wait...

Hmmm.

[Anonymous No.5547275]

>>5547253
The field is set up by the matter that created the black hole. The gravity doesn't need to propagate out. If there were a change in the gravity, that would need to propagate out.

[Anonymous No.5547277]

>>5547147
>>5547170
Redshift. Do you even into cosmology?
Yes the spacetime expands.

>>5547136
Basically, the analogy I use to be able to use my intuitive vision in GR is that when space-time expands, I visualize the classical distorted grid you see everywhere, and I imagine that each couple of points on this grid is seperated by 1m. The value of 1 meter changes, but not the number of meters considered. In this way, the light still has a velocity of <span class="math">3.10^8 m.s^{-1}[/spoiler], but the meter itself seems larger in my frame of reference.

[Anonymous No.5547280]

>>5547136

I've always been curious about what communications through a wormhole mean in this context since for all intents and purposes they are faster than light. Yet, jumping in and out of the wormhole shouldn't cause time travel or at least I wouldn't see why it should. But it certainly fits the bill of a closed time-like curve..

[metric !1tensorX8Q No.5547281]

Provided you could engineer an Alcubierre drive, you certainly could.

>put message in bottle
>send bottle in Alcubierre bubble
>????
>profit

[Anonymous No.5547283]

>>5547268
That's just a matter of understanding the theory. There are no experimental implementations of warp drives.

I'm sorry...what do you mean by that?


http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015936_2011016932.pdf

[Anonymous No.5547286]

>>5547275
But wouldn't that seem to imply that virtual particles are separate from space-time entirely? If that were the case how does magnetism arise, since it is a electric field being warped by relativistic effects of accelerating space.

[Anonymous No.5547320]

>>5547283
again with this shit? NASA is testing a unproven 5D general relativity which if proved to be correct would mean that you don't need negative mass for the warp drive. you still have the problems of radiation, impossible construction, no controls and causality violations.

[Anonymous No.5547324]

>>5547275
Wouldn't the frame dragging effect of a rapidly spinning black hole count as a change in gravity?

[Anonymous No.5547352]

>>5547320
What shit?

I'm not trolling here, i'm simply trying to make sense what your argument is for stating that there are no implementations for warp drives - of course there are, fuck man that kind of technology is awesome.

In regards to the problems, yes they are real, viable, and true problems which i cannot and will not refute, and i am not here for that shit.

You're saying "No, and never" and i'm asking "Why Not?" and saying "Never say never".

Chill.

[Anonymous No.5547364]

>>5547352
that was my first post. and why never? because:
you cant control it (in theory)
you cant build it (using theory of current known particles and interactions)
you cant survive it (in theory)
you cant use it (contradicts with current theories)

so its something we cant practical do, and our theories say its not possible. so there is absolutely no reason why this would be possible. you have something you want to be true and you are saying that well, maybe in the future all we know will turn out to be wrong, so its possible. thats just fantasy.

[Anonymous No.5547372]

>>5547364
>you cant use it (contradicts with current theories)
Nuh-uh, sir, i'll take what you wrote on all the others for granted, however wether it contradicts with current theories you're gonna have to give me a quote to spare.

[Anonymous No.5547380]

>>5547283
We can be pretty certain that no one in their right mind is going to try to make a warp drive following the principles of GR pretty soon. If that guy's looking for evidence of some alternate theory of gravity, then what he's doing might make sense. I wouldn't get my hopes up, though.

[Anonymous No.5547386]

>>5547372
ill paraphrase, i spent my quote point yesterday.

one of the main point of why warp drives are better people always use is that you dont get any time dilation due to being in the same frame as lets say the planet, but if you travel a distance while undergoing no time dilation you make it possible to have a 3rd observer travel in such a way that when the warp drive and the 3rd observer come back to the planet, the following happens:
the planet and warp drive didn't experience any time difference (maybe just the bit because of where you reversed direction.)
the rd observer would see that the warp drive aged more than the planet
some 4rth observer would see the planet aged more than the warp drive.

you cant have observers disagreeing about the relative tine difference of events at the same point, when thy are also at that point and in the same frame. there was paper about this from around 2003.

[Anonymous No.5549017]

>>5547386
http://arxiv.org/abs/grqc/0009013

>It is shown how, within the framework of general relativity and without the introduction of wormholes, it is possible to modify a spacetime in a way that allows a spaceship to travel with an arbitrarily large speed. By a purely local expansion of spacetime behind the spaceship and an opposite contraction in front of it, motion faster than the speed of light as seen by observers outside the disturbed region is possible. The resulting distortion is reminiscent of the ``warp drive'' of science fiction. However, just as it happens with wormholes, exotic matter will be needed in order to generate a distortion of spacetime like the one discussed here.

[Anonymous No.5549038]

>>5549017
If Alcubierre works for FTL, it also works for backwards time travel.

[Anonymous No.5549112]

>>5549038

Basically - no object is actually physically moving at FTL speeds. By GR it's impossible for a physical object to go faster than luminescent speeds on its own. And if it did ( like a hypothetical tachyon) it would go back in time. Which is not possible.

Alcubierre works differently, it does not violate GR in a sense that no object is actually physically "moving" but simply space itself. In a more layman perspective, it's more like "riding a wave."

This is nothing new, we are riding one right now, from the Big Bang, space accelerated (expanded) many times the speed of light, however the objects within them did not.

So no, no "Back to Future" time travel here.

[Anonymous No.5549140]

>>5549112
Nobody said it violates GR. Just that it enables backwards time travel. In fact, it is already backwards time travel if you just look at it from a different reference frame.

[Anonymous No.5549682]

>>5547275

Don't the theoretical micro blackholes in the LHC evaporate almost instantaneously? If it's impossible for the change of gravity to propagate out, wouldn't they be functionally permanent? and therefore those doomsday people be correct?

(Not that they are.)

[Anonymous No.5549696]

>>5549682
My impression (I could be wrong on some points) is that black hole evaporation is not so much about stuff from inside escaping as it is about stuff with negative energy falling in.

[Anonymous No.5549722]

is it true that an object mass increases as its velocity increases?
Or is that bullshit?

[transfer student F No.5549734]

>>5549722
you should leave lol

[Anonymous No.5549741]

>>5549722
Its energy increases. Some people used to refer to energy as "relativistic mass." Don't do this.

[Anonymous No.5549744]

>>5549734
you should answer my question lol.

I remember something about relativistic mass being different from mass but then there's a void in my brain

[Anonymous No.5549795]

Space doesn't necessarily expand FTL. The effects and changes of gravity are though which was the #1 problem with e = mc^2. Now a communication is done by any way of showing a man made change in something. So for there to be comm. you have to make a gravity change that can be relatively used like mores code and it has to be detectable. Moving your mouse changes gravity but so minor that it can't really be noticed so good luck with FTL communication.

[Anonymous No.5549862]

>>5549744
You should quit sucking dicks, lol.

[Anonymous No.5550016]

>>5549795
Not sure what your point is, but take a look at this:http://en.wikipedia.org/wiki/Gravitational_wave
and in the section of a "Effects of a Passing Gravitational Wave".

This is a luminal wave, not an ftl. So it would be somehow different than the grav wave that OP proposes.