CURSE you, EINSTEIN! Humanity still chained in relativistic PRISON Disappointing news on the science wires today, as new research indicates that a possible means of subverting the laws of physics to allow interstellar travel apparently doesn't work. Curses! Can nothing pierce this damned rubber sheet? As we are told in a new paper just published in hefty boffinry mag Science: Neutron …
I'm posting this anonymously as I'm sure there's a really, really, really easy answer to this thought experiment but I'm too thick to know it.
If I had a metal rod 100 million miles long sitting in a frictionless universe, and I push one end of the rod, surely the other end moves immediately, rather than taking however long light takes to travel 100 million miles. Which means that this violates the speed of light as nowt can travel faster than that, even information. I have heard about Quantum Entanglements and homeopathic medicine but assume this is not at all related as I have no idea what a quantum is except it's probably smaller than a peanut and am not sure what memory water really has.
Now I'm 100% positive that Einstein was brighter than me, indeed suspect the vast proportion of the world will fit that large set, but nobody has explained to me why my thought experiment is wrong.
Any takers who can write in crayon and use very, very small words? Please?
that amount of metal will have some compressibility
Any rod of metal has "some compressibility". The rigidity of a solid is the result of electromagnetic interactions, which are quite willing to redistribute mechanical force orthogonally to the axis of compression. So unless your "rod" is a single layer of atoms, it can always be compressed - it will just expand to the side as necessary.
And since mechanical force travels by propagating EM interactions, it can't travel down the rod faster than EM can propagate along it. There's no need to invoke compression for this thought experiment; the OP's assumption that the far end of the rod moves immediately is simply wrong. Atoms at the near end move, which decreases their distance to their nearest neighbors, which increases the electromagnetic force between them and their neighbors. Once that force propagates to the neighbors, the neighbors are accelerated by it and move in the direction that the rod is being pushed. Nothing happens immediately.
Equally not an expert on the subject, but the first flaw I notice is that your rod (snigger) is "sitting in a frictionless universe", which is automatically not our universe and so other laws of physics are non-comparable.
Other than that, I don't think I can be of much help. I'd assume material strength/elasticity, friction, force required, etc., would be enough to make it impossible.
On the entanglement side, though, my understand is that entanglement can potentially cause a correlated effect to occur instantly at a location over a light-year away, but this (with our current understanding) couldn't be used of itself to transmit information.
The common example (which I believe I've seen repeated by other commentards) is the "two cars" thought experiment:
You have two cars (one red, one blue) hidden under sheets, and both are moved a light-year away from each other. You remove the sheet from one car and immediately know the colour of the other car. You aren't receiving this information faster-than-light, but the effect appears to be the same from your position.
IANAQM
This is better put as "you have two cars, and if you ever check, one will be red and one will be blue, but at the moment because you haven't checked it's not decided - it's not a case that one is already red and you just don't know it. It isn't. The universe hasn't decided yet. It's not red. It's not blue. No decision has been made. When you look at one, the decision is made, and if the one you looked at is red, the other one will be blue whenever someone checks, even if they check a second later a light year away, so did some kind of information travel that light year in one second?"
The key thing is that the universe doesn't decide on the colours until you check.
Where the car analogy starts getting interesting is if you could reach under the blanket with a tin of blue paint and turn one of the cars blue without ever looking at it.
If the other car must be red because the one you just painted is blue then you've got a fun toy that you won't want to think too hard about.
Okay, I'll bite...
Imagining the rod to be constructed of a non-compressible material in a frictionless universe etc etc...
Both ends of the rod move at the same speed, which is as fast as you can push one end. This must be less than the speed of light.
As for information, well, it's not made of matter... so, excuse the pun, it doesn't matter...
Information is near enough the same thing. Everything in the universe is made of information and matter (or information and energy depending how you squint). "Nothing" can move faster than light in this universe (so far as we can tell with all our observations and calculations).
This should not be a problem though. It's only humans that are concerned with the speed of travel or progress, photons, protons and information can take as long as it wants. ;)
The metal rod is not infinitely rigid. Therefore it's like a very very stiff spring. When you push one end, the atoms are momentarily compressed, and pass that force onto the next atoms as they start to move and so on down the rod. You're pushing against the inertia of the rod, making your end accelerate. That wave of compression passes along the rod at less than the speed of light until the other end starts moving too.
When you stop pushing, the atoms at your end spring back, and eventually the whole rod returns to its original shape. Now the whole rod is moving through your frictionless universe, but the whole rod (including both ends) is moving at a steady speed. There's no actual 'change' (read 'information') going on anymore.
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There are no stupid questions :-) But this might be a stupid answer...
Compress your thought experiment back down to a hundred meters ... You hold one end and tap it - I hold the other and listen. What you are doing is (slightly) moving the rod and transmitting a wave - this travels at the speed of sound (albeit in metal - I think that's around 10x faster than in air) but it's a lot slower than light, never mind instantaneous.
Imagine if you will the venerable Saturn V rocket on the verge of takeoff. The rockets at the bottom fire and start pushing up the bottom of the rocket. However, the top of the rocket does not react momentarily. For that instant, the rocket compresses and propagates up the height of the rocket until the top start moving.
A similar thing can be observed with the humble Slinky. There is an El Reg article about a Slinky experiment that discusses the phenomenon at length.
Basically put, nothing in the universe is perfectly rigid. Apply a force at one end of the rod and, instead of the whole rod moving at once, the rod will compress at that end, and a compression wave will run down the length of the rod at subuminar speed. The other end won't react immediately because of this.
Incidentally, this compression phenomenon exists regardless of friction, as it can also occur in space where friction is as close to zero as we can get it.
I'm afraid that's physically impossible in so many ways.
A gravitational force would act along the axis of the rod, compressing the centre until it snapped. Even a small alignment error would cause the rod to twist and buckle as the ends were attracted to the centre. Unless you got your push perfectly aligned, the same thing would happen. (I've ignored the problem of not having the rod spinning in the first place.)
If you manage those problems, then there is no perfectly rigid material you could use to manufacture the rod so the best case is your "push" travels down the rod as a compression wave (sound wave) with the other end moving many years later. But it's more likely it would behave as if one end was anchored: rebounding elastically if the push was small; snapping if it was too big.
If I had a metal rod 100 million miles long sitting in a frictionless universe
A frictionless universe won't help you here. Instead you'd need an incompressible rod... not something you can make out of normal matter (see also: black holes). You push the end of the rod, you generate a compression wave, and that will travel at a finite speed even in incredibly dense material (do a quick search for 'speed of sound in neutronium', for example).
Now, I Am Not A Theoretical Physicist, but I rather suspect that you could only manufacture the required massless and incompressible rod if you already had some sort of superluminally propagating force, making it a bit of a circular argument!
Homeopathy does not work
Well, it does, but you have to choose your victims patients carefully. As homeopathy's effectiveness is equivalent to that of a placebo, it should be administered only to hypochondriacs and other true believers in order to properly "treat" what ails them.
In fairness, placebos are very effective for pretty much everyone. Bizarrely, it doesn't even matter much if you're told that you're taking a placebo. Oh, and it helps if you're charged a lot of money. Seriously.
Anecdotally, I was given homoeopathic medicine when I was covered in very virulent mosquito bites. It worked brilliantly within minutes, and I know that stuff is a load of bollocks.
As homeopathy's effectiveness is equivalent to that of a placebo, it should be administered only to hypochondriacs and other true believers in order to properly "treat" what ails them.
Studies have shown [sic] that the placebo effect works even then the patient knows they are receiving a placebo.
Homeopathy is total bollocks though, along with beliefs in 'crystal energy', any sort of 'quantum healing' and sky fairies.
I've thought about that as well. I think the rod will compress when you push on it. Even a miniscule amount of compression adds up over 100 million miles, and you're trying to move a lot of inert mass. Eventually the rod will decompress and the far end will move, but not simultaneously with the near end.
The rod could be completely mechanically incompressible (in the sense that the inter-atomic forces were effectively infinite) and the effect would still propagate at the speed of light since everything including forces propagates at the speed of light. The lightspeed limit is implemented at layer 1 of the universe.
Propagation is not instantaneous. Each atom bears some pressure and passes it on to the closest one.
Pushing on a 100 million miles long rod would not move the other end instantaneously.
You can actually easily test this in reality.
Just take a 2 meters long spring (ok, hard to get by but you can engineer one much more easily than a 300 million miles long pole). Push on one end.
By now you are imagining what's happening and you don't need to actually test it. It probably is obvious to you that the spring will compress some on your end beforespringing on the other end (and that'd be true even without and friction).
Well, your pole is the same. It's way less compressible than a spring, but then you'd have to apply inifinitely more pressure to actually give it the same acceleration as the spring. So in the end, it'd would compress, that compression would propagate at some speed actually probably way below the speed of light, and your thought experiment problem is solved.
All along it was not a real problem but just the fact that it's not a real thought experiment but just assuming that because you don't see the delay at our scale, there isn't one. Even at our scale, there is.
See also:
Dropping a slinky
The speed of sound in a slinky is much lower than the terminal velocity of the spring, if you hold one end of the spring and drop it, the bottom of the spring will not start moving before the top reaches it, as the acceleration under gravity will quickly cause its speed to exceed the speed of sound in the spring (the speed at which the compression wave propagates).
It's a cool experiment, but here's the question - when you let go of the top of the spring, does the bottom become weightless?
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VSauce covered this topic on their YouTube channel. The speed of push is slower than light, a lot slower. It actually moves around the speed of sound. You should check the video out, it's really cool. http://www.youtube.com/watch?v=Do1lm9IevYE around 5:15 is the bit about push speed.
"I'm posting this anonymously as I'm sure there's a really, really, really easy answer to this thought experiment but I'm too thick to know it."
Been there, done that!
"If I had a metal rod 100 million miles long sitting in a frictionless universe, and I push one end of the rod, surely the other end moves immediately,"
Actually, that's something I've wondered about too - though I would assume some whizzo rigid carbon nano wotsit or similar!
Your rod is actually just a chain of molecules, each bound to the others, in theory, by strong interaction. If all of the molecules in a chain 100 million miles long were to affect each other then this would certainly NOT instantly occur everywhere. Every single molecule along the way would have to interact with every molecule next to it along the entire length before the interaction would reach the other end. The rod is not a 'thing', but rather is a chain of molecules. It may well be that the other end of such a chain of molecules would not even move at all.
Not a supid question!
As others have mentioned, the inertia of the material comes into effect, as does its rigidity. These figures determine how fast a wave can travel through your material. In other words, the speed of sound. For steel, this is typically 5800 to 6000 m/sec, travelling as a compression wave. Attempt at ASCII art:
>|___|__|_||_|__|___|___|___...
Ignore the rod's other vibrational modes (e.g. longitudinal) because they'll be much slower.
If your hypothetical rod were 100 million miles long, most of it would be in free space, which is indeed pretty frictionless. Even if you used a more manageable 100m rod, (suggested by someone) then suspending it by threads would give an adquate approximation. Attach microphones to both ends, connect to amplifiers, detectors and a start-stop timer. Calibrate by moving the far mic upto the near mic (keeping the same long cable attached).
"
Stupid question
I'm posting this anonymously as I'm sure there's a really, really, really easy answer to this thought experiment but I'm too thick to know it.
If I had a metal rod 100 million miles long sitting in a frictionless universe, and I push one end of the rod, surely the other end moves immediately, rather than taking however long light takes to travel 100 million miles. Which means that this violates the speed of light as nowt can travel faster than that, even information. I have heard about Quantum Entanglements and homeopathic medicine but assume this is not at all related as I have no idea what a quantum is except it's probably smaller than a peanut and am not sure what memory water really has.
Now I'm 100% positive that Einstein was brighter than me, indeed suspect the vast proportion of the world will fit that large set, but nobody has explained to me why my thought experiment is wrong.
Any takers who can write in crayon and use very, very small words? Please?"
You really need to substitute in a hydraulic cylinder for your rod...
No no no, what you need is "Light Inextensible String", available by the mega-furlong
in any mechanics problem near you when you were 18 or so. You don't even need to
turn off friction.
Way back when there were still shops selling videodiscs (OK maybe I'm exagerating)
some friends and I proved that it violated causality.
As others have said, you're assuming a perfectly ridged body, and there isn't any such thing. In fact, special relativitive is ruling out perfectly ridged bodies. The mechanism is that you push one end, the interactions with the molecules, electrons, whtever pushing the next molecule along is takes a finite time, it's light speed limited.
Problem with your thought experiment: prior to carrying out the experiment, you have to get the rod into place. This would probably vitiate your attempt to actually do the experiment. As mentioned in another comment, tapping the end of the rod would set up a wave in the rod travelling at the speed of sound to the other end, not superluminal transfer of info!
It's like the famous twins paradox often cited in discussions of relativity, or at least the Lorentz equations, where the twin travelling at the speed of light does not age while his pedestrian brother gets old. What is not usually included in this anecdote is the fact that the travelling twin, on leaving his brother, will then have to accelerate up to the speed of light, and at the end of his journey, decelerate back down again, and these two phases of his journey will probably occupy as much time as would have been passed in the interim by his stationary brother. The relativity relevance of the story merely deals with their relative velocities once the moving twin has achieved light speed and before he comes "down to earth" from it.
I'll post this as a pedant - which I am - not as a 'simplicius'* enquirer.
*cf Galileo's dialogues.
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@HolyFreakinGhost
" We *can* write down loop quantum gravity, which is a first-quantised vacuum theory, but mapping from LQG up to GR is to my knowledge still an unsolved problem"
Which just goes to show that mathematics is a language, albeit a highly formalised and logical one. Languages can be used to write fiction as well as non fiction. When writing fiction, as the best show, you can describe perfectly internally consistent fictional universes, but they are not this universe. It has always seemed to me that many theoretical Physicists and String Theorists in particular forget this aspect of the language they write their theories in, and from this we get assumptions such as that the Mulitverse must be true because we can write consistent stories that require it to be true.
As an experimental biologist I just sit back and say: 'prove it'. Because such descriptions don't look like this universe. I'm all for throwing up testable hypotheses for the atom smashers and the cosmologists to go see if they are true, but they have to testable. If you are building castles in the air with untestable buttresses supporting untestable towers and resting on untested assumptions then you are not doing science any more.
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Thanks for that. While reading it I did find myself wondering if Gödel's theorem might apply to reality itself. The "universal constants" are the axioms and the mathematical relationships between them are the allowed rules of inference. Eventually we are bound to find some parts which can not, and can never be, reconciled.
Just a thought.
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You have hit upon a key issue in metaphysics.
Self reference. All systems of thought that attempt to describe a universe in which the thinker exists, are self referential and all can be shown to contain essentially Gödelian type statements.
Douglas Hofstader has explored this in some detail, and a very good outline description of the issues is Hilary Lawson's 'Closure' ..
In popular culture of course the issues is raised in the 'Matrix'. A completely artificial universe is totally indistinguishable from a 'real one' if it fools all the senses all the time.
Hilary Lawson's thesis is that it cant do that completely all the time, there will always be gaps. A place where some logical self referential statement will lead to complete and final uncertainty.
WE (and I) suspect that the most glaring place today in our current scientific worldview is indeed areas like quantum physics. With the illogical conclusions that whether the cat is dead or not is 'caused' by our consciousness of its state. In his idea system, its not just the cat. EVERYTHING is 'caused' by our perception of it, in the sense that the world-as-we-know-it is not the real or the final world. It is brought into being by our attempts to intervene with it., and that intervention consists of a separation of 'us' from 'it' which both defines what we are and defines what the world of our perceptions will be. This has an exact analogue in quantum physics where it is the attempt to intervene in quantum reality that causes it to 'collapse' into classical 4D space from a radically difference phase space.
All intersting ideas..
Given that every time we look very hard at something strange and new to observe it has a habit of proving Einstein right, maybe it's not relativity but quantum mechanics that has the glitches in it?
Beer, because after a few of those later that might make sense.
You can "go the other way" and merge the other forces with gravity. The EM field works fine (Kaluza-Klein) and then the program begins to struggle. However it would require extra (really tiny) dimensions and IIRC LHC is close to ruling that out.
wouldn't be practical though, would it?
if I understand it right, you would have to get near the collapsing neutron star first, in order to make use of the warped space/time and slingshot yourself to an equivalent point on the other side? so it's still going to take years and years to get from Earth to the nearest collapsing neutron star, isn't it?
Or is the solution to have a device onboard the ship that creates a collapsing neutron star of the right size as when you require it? I imagine the Health & Safety department of interstellar travel would have a field day with that though.
i guess, perhaps this does explain why we haven't been wiped out by an alien invasion force yet. maybe we're not alone in the universe, but there's just absolutely no way to get to the next door neighbours to say hi.
jai: "i guess, perhaps this does explain why we haven't been wiped out by an alien invasion force yet. maybe we're not alone in the universe, but there's just absolutely no way to get to the next door neighbours to say hi."
A similar argument applies to Time Travel - if it were possible, they'd already have visited.
Interestingly, one version of the Tardis (multiple writers = no consistency) is that it can only travel in ITS past. So Gallifrey is in our far distant future. This neatly avoids many paradoxes in that nothing that a Time Lord does affects their own future; they're always simply doing things that, potentially at least, were known to have been done already before they set out. The Time Lords can not change their own future except by acting in their present, just as we (think we) do; they can not travel forwards to see what effect decisions will have and thereby make different ones.
There is a vestige of this idea in that most Dr Who writers have stuck to the rule that the Doctor can only meet himself in extremely unusual circumstances which are dangerous to the structure of his own timeline. Aside from being a useful plot device rule, this can be seen as recognition of how much energy would be required to actually change one's own past by the transference of entropy from one "knowledge frame" to another and thereby alter the second frame, which is ultimately made up of all the states of matter in the universe.
Of course, most Dr Who writers don't worry about any of this and there's far from being a "one true" theory of Time in the show. Sadly, recent stories (particularly the dreadful stuff that Davis wrote) have in fact been overly concerned with the time travel aspect as a thing in itself and not so interested in just using time travel as a mechanism for getting the Doctor and his assistants into an interesting story.
Have a quick read of WIki History by Desmond Warzel for an entertaining view on timetravel.
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An alternative explanation could be that the Johnny Alien has picked up our radio transmissions and decided to give Earth the swerve on cultural grounds, viz., I have heard talk of the wonders of Blackpool's Golden Mile, but despite having the means to do so, have never felt the need to visit...
Time travel would be possible with infinite computational power. Traveling back in time would be a matter of examining the state of the universe, reversing its path in a virtual environment, and then entering that environment or overwriting the present with it. Altering the present from the past would be calculating what changes a past event would have and then applying them in the present. Altering the future would be predicting what changes would be needed to arrive there and applying them in the present. You could argue that it's not really time travel but, if done well enough, there'd be no way to know the difference. Extremely narrowly scoped examples can already been seen on the Internet, in history books, the financial market, and in good brain washing. The scope of such hacking will increase over time.
It has already been invented (or rather, is going to have already been invented). The reason why they haven't visited us to tell us about it, is that going back a few minutes or hours to make witty remarks which people only thought of some time after the event soon became by far and away the major commercial application for time travel, and as a consequence the range of commonly-available time machines is restricted.
if I understand it right, you would have to get near the collapsing neutron star first, in order to make use of the warped space/time and slingshot yourself to an equivalent point on the other side?
I admit I was thinking the same thing, but I've never gotten around to reading Haldeman's Forever War (I really should some day; I know it's a classic), so I don't know if he addresses this point.
According to one article, the closest known neutron star is 250-1000 ly away, so we'd still be needing the big suitcase.
Personally, my favorite fantasy space-travel mechanism is still Larry Niven's proposal to turn the entire solar system into a vehicle, by wrapping the sun with a big ol' ring of electromagnets (possibly in concert with building a full-on ringworld, because hey, while we're dreaming...), and then turning it into a really big ramjet aimed orthogonal to the ecliptic. Niven suggests that by the time you've thrown out an appreciable amount of solar mass (as reaction mass), you're scooping up enough interstellar hydrogen to make up for it. Now you have a "generation ship" that has the best life-support system anyone's ever seen. Just maneuver it into the neighborhood of an interesting stellar system, then use conventional rockets to visit. Space caravan!
Space has a critical matter density of 3.6 E minus 25 kg/cubic meter. Its components (elementary particles) are in a state of perpetual harmonic oscillation at a rate C at 3E +8 cycles per sec.. It provides the motivation to create the gravitational acceleration towards the centre of bodies because the wavelength of the oscillations get compressed and merges . The concept of velocity in space is wrong . Transmigration of pressure takes place as waves like in air as sound or water. There is an axiomatic theory that has the answers . See www kapillavastu dot com slash index html to get details.
sounds like you got it mixed up, it's Transformation, as in Transformative Hermeneutics of Quantum Gravity.
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I think Voyager's problem is it made manoeuvres along the way, and the uncertainty in those is larger than the Pioneer effect.
The Pioneer anomaly has been looked at in detail, and radiation leakage was a candidate for the answer, but nothing convincing has been found. Certainly I would be in favour of a mission designed to check this and establish with certainty if it was simply a spacecraft artefact, or something genuinely different in our understanding of gravity.
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Thanks for the link to that paper - a little more recent than the last I read on this, and as you say fairly convincing. Still, as you point out, it is still not answered to "discovery" levels of 3-sigma and above, and there is still galactic scale oddities to be addressed.
We cant probe that sort of distance, but we could do a gravity mission beyond Earth to help resolve the Pioneer anomaly, one way or another, for good.
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The force you impart to the rod propagates through the entire rod much faster than light speed, but all the molecules only increase velocity per the force imparted. This does bring up the question of gravity propagation, however. If a mass pops into space-time, is its gravity manifested everywhere in the Universe instantaneously or does it propagate out from the mass, and, if the latter, at what velocity does it propagate? Inquiring minds want to know.
The speed of gravity is apparently finite... I believe that's been known for some time. Newton thought it was infinite, but apparently observations of Mercury's orbit in the mid-1800s showed that the planet's behaviour could not be explained by purely Newtonian physics.
Modern work on the actual speed of gravity is pretty arcane. Current theories suggest that it isn't any faster than the speed of light, but the related papers are well beyond my ability to understand. Good luck ;-)
(also, "The force you impart to the rod propagates through the entire rod much faster than light speed"... really? if that were true, we wouldn't be arguing about the existence of superluminal physics still!)
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Why should we ever contact or do something more insane give a insane killer a gun and a car to roam the neighborhood. Man is a dangerous violent animal. So violent that we will never give him the knowable or tools to get him off his planet Earth. He will for all eternity be lockup on planet Earth
First, while Man is obviously dangerous to Man, it is the height of hubris to think the Universe is losing sleep over our popguns and petty bickering. Second, Man is no more violent than, say, bacteria. Or my cats, which fight constantly, for no apparent reason. Third, eternity is a very long time, and there is a great deal we still do not know.
As far as I can see, the findings presented in the article simply show an unrelated confirmation of Relativity, rather than a specific refutation of the possibility of Collapsar travel. Moreover, there remains a great deal we do not understand - such as why 95% of the Universe remains unaccounted-for, or why Relativity and Quantum Mechanics can't be reconciled. For starters. Milk and sugar in mine, thanks.
The gravitational force generated by a spherical (or any shaped) body is maximum at its surface, right? So when we have a neutron-star accreting material from a companion, as the mass builds to that necessary to form a black hole. The black hole will actually form at some point on the _surface_ of the neutron-star, right?
And I also liked The Forever War.
When Haldeman wrote The Forever War the term "collapsar" was what they were using for what we now routinely call a Black Hole. I remember Patrick Moore giving a presentation on this then-new postulated phenomenon on The Sky at Night.
Now if you want a good story about neutron stars, Larry Niven is your man, though his classic "Neutron Star" cannot work as written for reasons Niven goes into in Known Space (I think) and which I won't spoil because it is still a rip-roaring adventure that takes classic hard SF into the world of 70s cutting edge astrophysics. Niven's star drive in that universe is more entertaining too.
I recommend Forever War to everyone as a classic of rational hard SF and also as an answer to the then not-so distant Starship Troopers. If you want to know why, read Troopers first, then TFW.
Nearest star is 4 Ly away, travelling at accelerations humans can stand, years is definitely the minimum. Leaving aside the energy costs, it'd take nearly a year to hit C, so you'd have travelled about .5 LY in the first year.
Lorentz dilation doesn't take it down much in the velocity changing phase given that for a long chunk of speeding up and slowing down you'd be experiencing only minor dilation.
Of course at lightspeed (if such a thing were possible) you wouldn't experience time, but the two subjective years of speeding up and slowing down would be longer than a year my back of the envelope maths tells me.
Of course the bonus about accelerating to lightspeed and then travelling at it is that all journeys would,subjectively, take exactly the same time.
In reality of course the energy requirements get sufficiently onerous as you get faster that constant acceleration is a non-starter.
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The last sentence of the article was a classic "out" that seemed to invalidate the article content, or at least say "take this with a grain of salt." Einstein knew in physics that all bets are off. The universe is supposed to behave like this or that, at least in our region or "plane" (for lack of a better word) of space. Leave that region or "plane" and the rules of the party change.
Cheerio!
Feel free to adopt that motto if it makes you happy, but it's no consequentially different from simple subjective solipsism - believing that nothing outside the conscious self can be known. Of course in that case anything is always possible; all of your perceptions could be hallucinations.
But there's little point in taking solipsism as a substantive foundation - of trying to act based on it. And there's equally little point in trying to act on the belief that physics is different in parts of the universe we can perceive. Maybe so, but so what?
Formal and empirical results that challenge our models are interesting, because they suggest there's something new to know, and perhaps to do. Theories that challenge our models are sometimes interesting, because investigating them might lead to new formal or empirical results. Saying "maybe our models don't hold under some conditions that we have no empirical access to, and no formal mechanisms to describe" is chit-chat.
It's not as though the idea of a collapsar jump would be particularly useful even if it did work. Our distant descendants on a generational ship might be able to use one, but by the time they got there, assuming they were to leave right now, we'd have already colonized a couple of nearby solar systems.
Personally I'm still hoping for some brilliant physicist to come up with a practical way to make an Alcubierre drive. Of course they have to wait for some other physicist co come up with a way to harness exotic matter....and that physicist will have to wait till someone figures out how to produce exotic matter in significant quantities....which of course will have to wait till someone actually proves that the stuff exists....I'll stop now. My hopes of visiting Polaris in my lifetime are getting further away.
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There never has been any evidence of violation of Einstein's limit.
One reason is that it would imply violation of conservation laws. A nontechnical discussion related to this may be found at http://www.scribd.com/doc/35613144/Time-Travel
A slightly technical discussion is at http://www.scribd.com/doc/38202981/A-Simple-Proof-that-the-Speed-of-Light-is-the-Greatest-Possible
"You cant measure anything faster than your measuring stick."
So I can't measure any distance longer than my longest measuring stick? Except with Pythagoras's theorem I can measure any distance I like starting from wherever I like.
Seeing something move across the horizon is a matter of the number of degrees or arc seconds it transects per unit time. So, if you have a measuring stick of the size of a say a galaxy you have got to with triangulation you can sit and watch for things crossing that horizon at any given speed. Even light takes long enough to cross at galaxy scales that anything travelling that fast would be easily viewable and measurable, if of course it were reflecting or generating light. There are some stars orbiting the monster black hole at the centre of the galaxy and also on strange trajectories out of and around the galaxy that have been measured travelling at appreciable fractions of the speed of light.
At the other scale if you magnify your view slugs and snails become speedy as they transect the horizon quickly. Things moving under Brownian motion are quite speedy looking once you magnify them enough but their absolute speed is very slow. It's all relative you see. To observe fast moving things move back a long way, to observe slow moving things move much closer.
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Yeah, I fart in your general direction, downvoter! Are you some kind of liberal? A kumbaya-singing peter puffer? Do you not only believe that man's mind and the laws of nature can be bent to your irrelevant puny laws, regulations, Glass-Steagal acts and other retarded mental contortions, but will you not even stop at science and scientific definitions until the only legally allowed thesaurus conforms to your own personal idea of Goodthink and Correctspeak? I'm sure your postmodernism makes you hope that all which you consider ungood can be banned and be disappeared with just a bit of rewriting. HAH!
No it's not a stupid question, but a perfectly valid thought experiment. So don't be Anonymous, stand up proud and thoughtful!
Even if the rod was perfectly rigid, you would need a device at the far end of the rod to tell you that the rod had moved. That information coming back to you could only propagate at the speed of light. I'm guessing that your initial push would propagate at the speed of light because you are passing information to the sensing device at the far end.
It's rather perplexing how quantum mechanics would come into this.
On whould think this were a test of GR vs other theories of gravity, like MOND or TeVeS, as described in
http://en.wikipedia.org/wiki/Alternatives_to_general_relativity
One would not expect QM to come into this, like, at all. So, one starts off with space.com:
http://www.space.com/20826-einstein-gravity-theory-toughest-test.html
which gets it right. Then one passes over to livescience, which refers to the above:
http://www.livescience.com/29062-einstein-relativity-tested-again.html
... but the churner adds in QM for no good reason, probably because he doesn't quite grasp what's up.
El Reg doesn't link to livescience but I guess just saw the above, then threw in the wrongly used "collapsar" and from there wanders off to Haldeman and manfrommars territory.
So what's important about this? This is:
"Our results indicate that the filtering techniques planned for these advanced instruments (of gravitational wave detection) remain valid," said Ryan Lynch, a physicist at McGill University in Montreal.
Everything else is manure. Are YOU running einstein@home on your Tesla card?
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Ignoring energy required (engineering problem solvable at some scale) and getting blasted to bits by high frequency photons (bit harder, but a bunch of ions helps). You can get anywhere you want because time slows down as you approach the speed of light. To an external observer you turn into a blue shifted or red shifted strangely shaped thing, that still can't get anywhere faster than light.
So long as you aren't trying to build an empire and run it, this is all OK.
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