Does anyone believe that Einstein is wrong?

[swansont]

I have read on forums at times that light speed has been found to vary. I also believe the red shift in light from stars moving away from us proves the speed of light has slowed down in reaching us, and it is not a constant in all reference frames.

I also think the michelson morley experiment was not accurate enough when it was done to establish light speed to be a constant.

 

You should read better quality forums. It doesn't matter what you believe, it's a matter of what you can back up with evidence. If light were not constant in all inertial reference frames, your radio wouldn't work (constant c is part of Maxwell's equations). GPS wouldn't work (relativistic offsets, both gravitational and kinematic).

[Peron]

Their have been experiments done to show that their are kinks in special relativity. Like the faster than light part.

 

Anyone heard of Quantum Entanglement?

 

Or the double slit experiment, one photon existing at two places at once.

 

Information has been sent faster than light, already.

 

I think, if mass increases the faster you move, then somehow you could, decrease the mass and go faster than light!

[D H]

Their have been experiments done to show that their are kinks in special relativity. Like the faster than light part.

 

Anyone heard of Quantum Entanglement?

Quantum entanglement does not violate the speed of light. Information cannot be sent faster than light.

 

Or the double slit experiment, one photon existing at two places at once.

That doesn't disprove SR.

 

Information has been sent faster than light, already.

No, it hasn't.

 

I think, if mass increases the faster you move, then somehow you could, decrease the mass and go faster than light!

First off, you cannot decrease your rest mass. Secondly, massless (e.g. photons) travel at the speed of light.

[Peron]

Hmm, did I say anything about disproving SR??

 

Sorry people shouldnt say things they dont understand.

 

http://www.daviddarling.info/archive/2002/archiveSep02.html#lightbarrier

 

2.3 Quantum teleportation. Teleportation is an old idea in science fiction. A person steps into a booth here, and is instantly transported to another booth miles or possibly light-years away. It's a wonderfully attractive concept, especially to anyone who travels often by air.

 

Until 1998, the idea seemed like science fiction and nothing more. However, in October 1998 a paper was published in Science magazine with a decidedly science-fictional title: "Unconditional Quantum Teleportation." In that paper, the six authors describe the results of an experiment in which quantum teleportation was successfully demonstrated.

 

We have to delve a little into history to describe why the experiment was performed, and what its results mean. In 1935, Einstein, Podolsky, and Rosen published a "thought experiment" they had devised. Their objective was to show that something had to be wrong with quantum theory.

 

Consider, they said, a simple quantum system in which two particles are coupled together in one of their quantum variables. We will use as an example a pair of electrons, because we have already talked about electron spin. Einstein, Podolsky, and Rosen chose a different example, but the conclusions are the same.

 

Suppose that we have a pair of electrons, and we know that their total combined spin is zero. However, we have no idea of the spin of either individual electron, and according to quantum theory we cannot know this until we make an experiment. The experiment itself then forces an electron to a particular state, with spin up or spin down.

 

We allow the two electrons to separate, until they are an arbitrarily large distance apart. Now we make an observation of one of the electrons. It is forced into a particular spin state. However, since the total spin of the pair was zero, the other electron must go into the opposite spin state. This happens at once, no matter how far apart the electrons may be.

 

Since nothing—including a signal—can travel faster through space than the speed of light, Einstein, Podolsky, and Rosen concluded that there must be something wrong with quantum theory.

 

Actually, the thought experiment leads to one of two alternative conclusions. Either there is something wrong with quantum theory, or the universe is "nonlocal" and distant events can be coupled by something other than signals traveling at or less than the speed of light.

 

It turns out that Einstein, Podolsky, and Rosen, seeking to undermine quantum theory, offered the first line of logic by which the locality or nonlocality of the universe can be explored; and experiments, first performed in the 1970s, came down in favor of quantum theory and a nonlocal universe. Objects, such as pairs of electrons, can be "entangled" at the quantum level, in such a way that something done to one instantaneously affects the other. This is true in principle if the electrons are close together, or light-years apart.

 

To this time, the most common reaction to the experiments demonstrating nonlocality has been to say, "All right. You can force action at a distance using `entangled' particle pairs; but you can't make use of this to send information." The new experiment shows that this is not the case. Quantum states were transported (teleported) and information was transferred.

 

The initial experiment did not operate over large distances. It is not clear how far this technique can be advanced, or what practical limits there may be on quantum entanglement (coupled states tend to decouple from each other, because of their interactions with the rest of the universe). However, at the very least, these results are fascinating. At most, this may be the first crack in the iron straitjacket of relativity, the prodigiously productive theory which has assured us for most of the 20th century that faster-than-light transportation is impossible.

 

http://www.webscription.net/chapters/0671319531/0671319531.htm

[mooeypoo]

Peron, from what you wrote in the beginning, you seem to be the one who misunderstands. If you want to put forth some evidence of why you're right, a science fiction author is probably one of the least convincing.

 

On top of that, there are some people here with some years of training and education in Physics, which by itself may not mean they're right (that would be 'appeal to authority') but it might hint as to the fact they are not completely clueless, and that what they say does have a basis in physics.

 

If you don't understand something, ask. Don't make a definite claim on something that you can't prove with anything other than a random cite of a popsci (barely) book.

 

Peer review, yes?

 

~moo

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Peron, from what you wrote in the beginning, you seem to be the one who misunderstands. If you want to put forth some evidence of why you're right, a science fiction author is probably one of the least convincing.

 

On top of that, there are some people here with some years of training and education in Physics, which by itself may not mean they're right (that would be 'appeal to authority') but it might hint as to the fact they are not completely clueless, and that what they say does have a basis in physics.

 

If you don't understand something, ask. Don't make a definite claim on something that you can't prove with anything other than a random cite of a popsci (barely) book.

 

Peer review, yes?

 

~moo

[D H]

Hmm, did I say anything about disproving SR??

Of course you did. You specifically said information has been sent faster than light. That would disprove special relativity.

 

Information never has been sent faster than light. Every claim that it has has turned out to be either a mistake on the part of the researchers making the claim, or more often misinterpretation/misrepresentation by someone writing a lay article about the topic. There's a lot of crud out there on the internet. Take care that you don't step in it.

[MM6]

Proponents of MOND (modified Newtonian dynamics) think Einstein is "wrong."

 

Einstein may be proven wrong in the future, just as Einstein proved Newton wrong, who along with Galileo proved Aristotle wrong. It happens.

 

(I'm not necessarily a proponent of MOND, btw. Just putting it out there.)

[Peron]

Well, Special relativity has been proven.

I am not saying it hasn't, and if something is sent faster than light does not disprove the theory.

 

Particles in a accelerator come close to the speed of light, but they cannot go faster than light, not matter how much more energy they put into the device.

 

Their must be something happening. And humans have the ability to adapt to nature. Like gravity. IT was impossible one hundred years ago to go into space, not we have hundreds of devices orbiting the earth.

 

I want to believe that one day we will over come the light barrier.

 

The point is that particles can exist in two places at once. We live in a non-local universe. Action can happen at a distance.

Particles do disappear here and appear their, all the time in labs.

 

All, I am saying maybe one day we will travel faster than light. I am not trying to disprove anything.

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I have a question, why doesn't light experience time dilation?

 

Or does it?

[iNow]

I have a question, why doesn't light experience time dilation?

 

Or does it?

If light did experience time dilation, then (since it's traveling AT the speed of light) it would experience infinite dilation, and time would basically stop relative to everything else. However, it doesn't help to think about it in this way, as it doesn't make sense.

 

The reason it does not make sense is because something needs to have a valid rest frame in order to view/measure experience from that objects frame of reference. Since light is never at rest (it always, by definition, travels at the speed of light), it does not have a valid frame of reference, and therefore does not experience the time and length dilation/contraction we use when describing the experience of actual (valid) reference frames.

 

Again, light has no rest frame, and therefore it is meaningless to try applying the concepts of time dilation, time contraction, length dilation, and length contraction. IINM...

[mooeypoo]

No, no no, light has no mass, it doesn't "experience" anything. As far as I know, we don't treat the photon as having its own inertial frame. Part of the reason is because it's there is no "inertial frame" for light, it's always the same velocity in all inertial frames.

 

So.. talking about the time dilation that light experiences makes no sense.

[Klaynos]

Peron, one of the things with science, is that no theory is ever beyond doubt, we know SR has a limiting condition, which is why we have general relativity. If something came along and showed that information can travel faster than the speed of light then we would have to redraw the lines around where SR is relevant.

[swansont]

All, I am saying maybe one day we will travel faster than light. I am not trying to disprove anything.

 

One must be careful to discern between scientific barriers and engineering ones. The speed of light, absolute zero, and overunity energy production would be examples of scientific barriers. Launching someone to the moon was an engineering barrier.

 

And this conjecture of yours requires that SR be wrong, so disproving it is part and parcel of your position.

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The initial experiment did not operate over large distances. It is not clear how far this technique can be advanced, or what practical limits there may be on quantum entanglement (coupled states tend to decouple from each other, because of their interactions with the rest of the universe). However, at the very least, these results are fascinating. At most, this may be the first crack in the iron straitjacket of relativity, the prodigiously productive theory which has assured us for most of the 20th century that faster-than-light transportation is impossible.

 

 

Not a crack at all. Rather, it tells you that certain quasi-classical interpretations of QM are wrong. The particles are entangled, therefore all of the information about that state of both particles may be obtained by measuring one of them, because that is a measurement which collapses the wave function. This, as opposed to thinking that the particles must superluminally communicate with each other. There's nothing in quantum teleportation that inherently violates relativity.

[bombus]

Einstein was not wrong. He was undoubtedly correct. However, new discoveries could modify his theories, or at least put them into a new context, much as Einstein's theories did to Newton's (who was not 'wrong' per se!)

 

I personally think the next revolution in science will come from the study of consciousness and may put everything in a very different context indeed - but that's just speculation:-)

Edited May 24, 2009 by bombus

[kkris1]

Einstein was not wrong. He was undoubtedly correct. However, new discoveries could modify his theories, or at least put them into a new context, much as Einstein's theories did to Newton's (who was not 'wrong' per se!)

 

I personally think the next revolution in science will come from the study of consciousness and may put everything in a very different context indeed - but that's just speculation:-)

 

Hi bombus,

I do not think you can prove any theory once and for good. You can have 100's of "proofs" to support a theory, but if you find one experiment which disagree with it, your theory is wrong.

As for Einstein, I think he was wrong on number of occassions. Look at his reasoning regarding time dilation or simultaneity:

 

I would like to comment on Einstein’s “thought experiment” regarding time dilation. In his explanation the light was reflected from the mirror on the ceiling inside boxcar travelling in horizontal direction in regard to stationary observer. It was concluded that even if the light was emitted perpendicular to the mirror, for external observer it would appear to be travelling on angle. Because speed of light is constant, therefore time would have to be longer. But what if there are two light rays , one red and one blue , emitted simultaneously as shown on the diagram below?

 

(see attachement, I couldn't copy the diagrams accross)

 

 

For stationary observer the light would appear to travel shorter distance (blue ray) in longer time!

 

 

 

 

Also so called “simultaneity thought experiment” appears to be naïve and entirely wrong. Let’s recall the Einstein’s scenario: Quote“

 

UP to now our considerations have been referred to a particular body of reference, which we have styled a “railway embankment.” We suppose a very long train travelling along the rails with the constant velocity v and in the direction indicated in Fig. 1. People travelling in this train will with advantage use the train as a rigid reference-body (co-ordinate system); they regard all events in reference to the train. Then every event which takes place along the line also takes place at a particular point of the train. Also the definition of simultaneity can be given relative to the train in exactly the same way as with respect to the embankment. As a natural consequence, however, the following question arises: 1

Are two events (e.g. the two strokes of lightning A and B) which are simultaneous with reference to the railway embankment also simultaneous relatively to the train? We shall show directly that the answer must be in the negative.

 

FIG. 1.

2

When we say that the lightning strokes A and B are simultaneous with respect to the embankment, we mean: the rays of light emitted at the places A and B, where the lightning occurs, meet each other at the mid-point M of the length A —> B of the embankment. But the events A and B also correspond to positions A and B on the train. Let M' be the mid-point of the distance A —> B on the travelling train. Just when the flashes 1 of lightning occur, this point M' naturally coincides with the point M, but it moves towards the right in the diagram with the velocity v of the train. If an observer sitting in the position M’ in the train did not possess this velocity, then he would remain permanently at M, and the light rays emitted by the flashes of lightning A and B would reach him simultaneously, i.e. they would meet just where he is situated. Now in reality (considered with reference to the railway embankment) he is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A. Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A. Observers who take the railway train as their reference-body must therefore come to the conclusion that the lightning flash B took place earlier than the lightning flash A. We thus arrive at the important result: 3

Events which are simultaneous with reference to the embankment are not simultaneous with respect to the train, and vice versa (relativity of simultaneity). Every reference-body (co-ordinate system) has its own particular time; unless we are told the reference-body to which the statement of time refers, there is no meaning in a statement of the time of an event. 4

“

end of quote

 

Now let us reiterate the logic of the experiment: two lightning bolts strike simultaneously both ends of a boxcar leaving the marks on the ground and on the boxcar. For an external observer O both strikes appear to be simultaneous however for the observer O’ who is right in the middle the flash of light from the front of the car arrives faster than from the back, because the boxcar “is hastening” towards the flash. But if the event is not simultaneous for the person in the middle, it should also appear the same for everybody else inside the car since they all are in the same inertial frame and they can synchronise their watches to confirm the exact moment the lightning occurred. If we happened to have extra 2 observers, one at the back and one at the front, they could indeed record exact time of event and confirm that the two strokes happened at exactly the same moment.

But there is still more to it. If the one at the end of the boxcar measured the time after which the light from the front lightning arrived to him (and knowing the length of the boxcar), he would think that either his time flows slower or the light travels faster than c. Similarly the observer at the front of the car would think (after measuring the time the light took to travel from the end to the front of the car) that the speed of light is slower than c or his time runs faster. However both front and end observers are in the same inertial frame, so if there is a time expansion or contraction, it should be the same for both of them.

Time dilation.doc

[Janus]

I apologize for not reading the rules of conduct. But here is how I see relativity. If a clock is moving away from you near the speed of light it will appear to slow down only because its takes the light longer to reach your eyes. It does not mean that time is really slowing down.

 

You are describing the Doppler effect, not Relativity. Relativity predicts a difference in the clocks besides that accounted for by the increasing light propagation delay. Relativistic time dialtion is independent of the direction the clock is traveling; It can be moving away or towards you and the clock will run slower.

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Hi bombus,

 

Now let us reiterate the logic of the experiment: two lightning bolts strike simultaneously both ends of a boxcar leaving the marks on the ground and on the boxcar. For an external observer O both strikes appear to be simultaneous however for the observer O’ who is right in the middle the flash of light from the front of the car arrives faster than from the back, because the boxcar “is hastening” towards the flash. But if the event is not simultaneous for the person in the middle, it should also appear the same for everybody else inside the car since they all are in the same inertial frame and they can synchronise their watches to confirm the exact moment the lightning occurred. If we happened to have extra 2 observers, one at the back and one at the front, they could indeed record exact time of event and confirm that the two strokes happened at exactly the same moment.

But they won't. If their clocks are synchronized to each other they will record different times for the strikes.

This is easily shown by considering length contraction. The ends of the train and the strike points on the ground are an equal distance apart in the ground frame. But the train is length contracted in the ground frame. In the train frame the train is its proper length and it is the ground that is length contracted. Thus the distance between the strike points on the ground is shorter than the length of the train . So when the front of the train reaches its strike point and records the strike, the rear of the train hasn't yet reached its strike point. Then some time later, the rear of the train reaches its strike point and records the strike, and the two observers record different strike times.

Edited May 26, 2009 by Janus
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[swansont]

Lorentz transformations are invertible, i.e. you can transform from A to B and then do the reverse transform and get back to A. Thus, you cannot do a thought experiment, using relativity, which negates relativity. If you get an inconsistent answer, it means you applied the theory incorrectly or made a math error. IOW, once you have removed any kind physical experiment from the discussion, it is no longer a physics problem. It is then a math problem, and you are discussing the shortcoming of math.

 

The only way to disprove relativity is by actual experiment disagreeing with the predictions of the theory.

[Klaynos]

There is infact a relativistic dopplar effect and a non-relativistic one...

[kkris1]

Now consider the situation: observers at both ends of the boxcar can measure the time of the strike at their respective ends If the transition time can be neglected, they can compare the recorded time and state indeed that the event were simultanous.

If they measure the time the signal has arrived from opposite end of the car, their statements would be, according to Einstein's reasoning, totaly different. For the observer at the end of the boxcar, the boxcar will be "hastening" towards the light from the front flash. The observer at the front will be receding from the signal from the back of the boxcar. So the observer from the back of the car will record the interval between two flashes being shorter than observer from the front of the boxcar. But they are both in the same inertial frame and should get the same results.

[Janus]

Now consider the situation: observers at both ends of the boxcar can measure the time of the strike at their respective ends If the transition time can be neglected, they can compare the recorded time and state indeed that the event were simultanous.

If they measure the time the signal has arrived from opposite end of the car, their statements would be, according to Einstein's reasoning, totaly different. For the observer at the end of the boxcar, the boxcar will be "hastening" towards the light from the front flash. The observer at the front will be receding from the signal from the back of the boxcar. So the observer from the back of the car will record the interval between two flashes being shorter than observer from the front of the boxcar. But they are both in the same inertial frame and should get the same results.

 

I already explained in my post on the last page why the observers on the ends will not record the same time for their respective flashes.

 

Also, the observers on the train do not see themselves "hastening towards" or "receding from" the light. This is the whole point of the example. In the train's frame the light takes the same time to travel from either end to the middle of the train, or from either end to the other.

 

It is in the platform frame in which the train hastens towards or recedes from the light. Thus in the train frame the observer in the middle reaches the forward flash before the rear flash.

 

This must be agreed upon by the observer on the train (For him to not to would lead to a contradiction).

 

Since the train observer sees the flashes at different times, and he knows that it takes each flash an equal time to travel the distance between the strike and him, he must conclude that the strikes did not occur at the same time.

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Here's a pair of animations showing the sequence of the events in both the ground and train frames

 

The first shows the ground frame's perspective. The red balls on the ground mark where the lightning strikes and leaves "char marks" on the ground.

 

The flashes originate at the ends of the length contracted train at the instant the middle of the train passes the ground observer. The flashes arrive simultaneously at the ground observer, but the leading flash reaches the train observer before the trailing one does. In fact, the train observer just about reaches the char mark of the lead flash before the trailing flash catches up to him.

 

 

The next shows the same events from the perspective of the train.

In this frame, it is the ground that is length contracted. The front of the train reaches its point of lightning strike first, and then the rear of the train reaches its strike point. Thus the flashes do not originate simultaneously. The front flash reaches the train observer first and then the rear flash. Note that the flashes still arrive at the ground observer simultaneously, and that the rear flash again reaches the train observer when he is almost even with the front char mark.

 

This is the sequence of events for any observer in the train's frame.

 

[kkris1]

If you look closely at your animation, you will see that the flashes at both ends of the boxcar are simultaneus. So two observers will record the same time for the flashes close to them. (If say there is the screen in the middle blocking the flash from the far end, and the two observers have to compare their recorded times)

Also according to your animation, there will be an observer somwhere past the middle point, to whom both signals will arrive at the same time. He is still in the same reference frame, but will strongly disagree with the guy in the middle

[Severian]

I think Special Relativity is the 100% correct description of dynamics on a flat geometry.

 

I think General Relativity is an incomplete description of gravity, but only because it isn't a quantum theory. But to say it is 'wrong' is, well, wrong.

[Janus]

If you look closely at your animation, you will see that the flashes at both ends of the boxcar are simultaneus.

This is only true in the ground frame

(first animation) the second animation shows what happens in the train frame.

So two observers will record the same time for the flashes close to them. (If say there is the screen in the middle blocking the flash from the far end, and the two observers have to compare their recorded times)

Again, as per the second animation, which show things from the train's frame the rear observer doesn't reach the spot of the lightning strike until after the front observer has past his, thus they cannot record the same time for their strikes.

 

Also according to your animation, there will be an observer somwhere past the middle point, to whom both signals will arrive at the same time. He is still in the same reference frame, but will strongly disagree with the guy in the middle

 

Do not confuse "seeing the flashes simultaneously" and "the lightning strikes occuring simultaneously". The observer near the rear of the train may see the flashes at the same time, but he also knows that he is closer to the source of one flash than he is to the other. Since light, as measured by him, must travel at the same speed from the back of the train as it does from the front of the train, it must take more time for light to reach him from the front of the train. Ergo, for him to see the flashes at the same time, he must conclude that rear flash must have originated after the front one.

 

This is exactly what the observer in the middle of the train concludes, as he is an equal distance from the strikes, but sees the rear flash later than the front flash. He, and every other observer anywhere in the train's frame, will agree that the front lightning strike occured before the rear one did, just as every observer in the ground frame concludes that they occured simultaneously.

 

You seem to be missing the whole point of this exercise.

[bombus]

Hi bombus, I do not think you can prove any theory once and for good. You can have 100's of "proofs" to support a theory, but if you find one experiment which disagree with it, your theory is wrong.

 

Well that's not quite true. Newton was not really 'wrong'. Newtonian physics still works perfectly well in most scenarios and applications. Even rocket science is mostly Newtonian physics (relativity tends to only play a significant part when huge distances, or very high speeds are involved).

 

Similarly, I doubt Einstein will ever be thought of as wrong, but new discoveries might modify his theories.

[foodchain]

OK thanks.

 

Its not that you are right on wrong about gravity as understood currently being right or wrong, just that you don’t even use the word theory properly in the first place.

[kkris1]

The second animation is not reflecting the truth of the Einstein's "thought experiment"

He stated clearly: "two lightning bolts strike simultaneusly both ends of the boxcar leaving the marks on the car and on the ground". If the strikes occurred at the same time, detectors at both ends of the boxcar would record the same time of the strikes. The animation is quite nice but totaly untrue, it does not reflect the "thought experiment" devised by Einstein. He said that the boxcar will be "hastening"towards the signal from the front, while "receding"from the signal from the back. That was the contradiction to his own postulate that the speed of light is constant, regardless of the frame of reference

 

On your first animation the flash reaches the front and the back of the boxcar at the same moment. The detectors at both ends would be activated exactly at the same time. If they were emitting the light, say one red and one blue, both red and blue rays should reach the middle of the boxcar simultaneusly.

The second animation shows entirely different scenario, it is just not from the same experiment.