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# Special Relativity - Einstein's wrong??? Tweet

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1. Special Relativity - Einstein's wrong???
Just thought of a physics experiment to possibly prove Einstein wrong with "No experiment can be performed to say which object is moving and which one is just standing still when just two objects are present. Reference to an external reference frame cannot be used as there are only two objects."

Experiment:

Use two lasers from opposite ends of the room
Detectors for both the lasers will be placed with extremely precise stop watches
The two lasers will be switched on simultaneously
If both the lasers are detected at the same time by the detectors then the room is not moving. If there is a gap in time of detection in the room is moving.

I have created a simulation to prove this. The link is given below. I think this is correct and works because light will always travel at 300000000 m/s vacuum regardless the velocity of the source of light.

Regards

2. Re: Special Relativity - Einstein's wrong???
Look up the Michelson-Morley experiment.
3. Re: Special Relativity - Einstein's wrong???
(Original post by Sagga)
Just thought of a physics experiment to possibly prove Einstein wrong with "No experiment can be performed to say which object is moving and which one is just standing still when just two objects are present. Reference to an external reference frame cannot be used as there are only two objects."

Experiment:

Use two lasers from opposite ends of the room
Detectors for both the lasers will be placed with extremely precise stop watches
The two lasers will be switched on simultaneously
If both the lasers are detected at the same time by the detectors then the room is not moving. If there is a gap in time of detection in the room is moving.

I have created a simulation to prove this. The link is given below. I think this is correct and works because light will always travel at 300000000 m/s vacuum regardless the velocity of the source of light.

Regards

the room in your simulation is accelerating and not moving at a constant speed. if your experiment worked then this should also take place if the room was stationary (relative to earth) because the earth is moving
4. Re: Special Relativity - Einstein's wrong???
(Original post by Sagga)
Just thought of a physics experiment to possibly prove Einstein wrong with "No experiment can be performed to say which object is moving and which one is just standing still when just two objects are present. Reference to an external reference frame cannot be used as there are only two objects."

Experiment:

Use two lasers from opposite ends of the room
Detectors for both the lasers will be placed with extremely precise stop watches
The two lasers will be switched on simultaneously
If both the lasers are detected at the same time by the detectors then the room is not moving. If there is a gap in time of detection in the room is moving.

I have created a simulation to prove this. The link is given below. I think this is correct and works because light will always travel at 300000000 m/s vacuum regardless the velocity of the source of light.

Regards

As someone said, look up the Michelson Morley experiment as this is strikingly similar.

The flaw in this is that your frame of reference is stationary compared to both lasers, therefore they'll appear to hit the other side of the room at exactly the same time.

If you were to 'stand' in space looking at earth, then you would see one beam hit the other side of the room before the other.

This is hard to grasp at first, but BOTH perspectives are valid and correct.

A better example is two cars travelling at exactly the speed of light. The one at the back has his headlights on and is reading the numberplate of the car in front. An observer at the side of the road cannot read the numberplate at the back of the first car as the light does not go faster than the cars themselves. Again, both view points are correct.
5. Re: Special Relativity - Einstein's wrong???
Simultaneity is relative. Two events separated by a distance which appear simultaneous in your reference frame wouldn't necessarily appear simultaneous to an observer moving with respect to your reference frame. The speed of light appears the same to all observers regardless of their reference frame, and so you'd see the light strike either end of the room at the same time. From the point of view of an observer with respect to whom your room is moving, however, one beam of light has to travel a shorter distance and so the light would strike one end of the room before the other. There is nothing to give priority to one reference frame over the other, and so you cannot say with any certainty at all that the room is stationary.
6. Re: Special Relativity - Einstein's wrong???
What if the room was moving perpendicular to the laser beams? Then surely the experiment would not work
7. Re: Special Relativity - Einstein's wrong???
yes torakrubik your point is i think valid point..

Last edited by mahnoorbloch; 23-04-2012 at 11:15.
8. Re: Special Relativity - Einstein's wrong???
(Original post by torakrubik)
What if the room was moving perpendicular to the laser beams? Then surely the experiment would not work
So you're saying that since the experiment wouldn't work, you could tell the difference between two free float frames correct?

Relativity would still hold. It's just that an external viewer would see light travelling with both horizontal and vertical components. hence since c is constant the horizontal component in red is less than the speed of light. What we observe here is time contraction whereas when we do the experiment with the box moving parallel to the direction light travels we observe length contraction.

Edit: Notice how in both cases the light starts from the same point on the left hand side of each box and ends up at the same place on the right. Hence there is no paradox.
Last edited by Lord of Ruin; 21-04-2012 at 10:56.
9. Re: Special Relativity - Einstein's wrong???
(Original post by Manitude)
As someone said, look up the Michelson Morley experiment as this is strikingly similar.

The flaw in this is that your frame of reference is stationary compared to both lasers, therefore they'll appear to hit the other side of the room at exactly the same time.

If you were to 'stand' in space looking at earth, then you would see one beam hit the other side of the room before the other.

This is hard to grasp at first, but BOTH perspectives are valid and correct.

A better example is two cars travelling at exactly the speed of light. The one at the back has his headlights on and is reading the numberplate of the car in front. An observer at the side of the road cannot read the numberplate at the back of the first car as the light does not go faster than the cars themselves. Again, both view points are correct.
K, I'm not a physics student or anything so I have to admit that I can't understand your frame of reference thing.

However, I'm fairly sure your car analogy is incorrect. Doesn't time stop at the speed of light? If so, how could you possibly read the number plate in front of you? Nothing happens at the speed of light. Alternatively (I'm not too sure about this second part), if you were say travelling at 99.9999% of the speed of light, light would still be moving faster than your car by 0.0001% of the speed of light. However, time has slowed sufficiently that you perceive light to be moving at the normal speed. But wouldn't a stationary observer eventually read the numberplate in front because light is still moving? It might take a longer time, that's all.
10. Re: Special Relativity - Einstein's wrong???
(Original post by Aeonstorm)
K, I'm not a physics student or anything so I have to admit that I can't understand your frame of reference thing.

However, I'm fairly sure your car analogy is incorrect. Doesn't time stop at the speed of light? If so, how could you possibly read the number plate in front of you? Nothing happens at the speed of light. Alternatively (I'm not too sure about this second part), if you were say travelling at 99.9999% of the speed of light, light would still be moving faster than your car by 0.0001% of the speed of light. However, time has slowed sufficiently that you perceive light to be moving at the normal speed. But wouldn't a stationary observer eventually read the numberplate in front because light is still moving? It might take a longer time, that's all.
The thing with time is that everybody always feels as though time is going at the same rate. However if someone were to hold a clock and stand still, and another person were to hold a clock and travel very close to the speed of light, both people would see their own clock ticking away as usual, but they would see the other clock hardly moving at all. Relativity does not define who is stationary, both can argue that they are stationary and the world is moving around them and both frames of reference are correct, even if they provide very VERY different viewpoints (such as in the car example)

If I go back to the car analogy I'll answer your questions. Yes, time does appear to stop at the speed of light, but as I said before, if you were in one of these cars you wouldn't notice this - everything else would appear to be stopped! Also with length dilation you'd be infinitely thin to an observer outside your frame of reference.

If you were travelling at 99.9999% the speed of light then to an observer outside of your frame of reference then the light would overtake your car by 0.0001% the speed of light. But the driver of the car would see the light travelling away from him/her at 100% the speed of light. The point with this analogy is that is seems so very counter intuitive, but stands up to reason and the maths.

Relativity requires you to throw away the concept of an absolute frame of reference and an absolute outcome to a situation, as it often depends on where you are standing.

Hope that clears it up.
11. Re: Special Relativity - Einstein's wrong???
(Original post by Manitude)
The thing with time is that everybody always feels as though time is going at the same rate. However if someone were to hold a clock and stand still, and another person were to hold a clock and travel very close to the speed of light, both people would see their own clock ticking away as usual, but they would see the other clock hardly moving at all. Relativity does not define who is stationary, both can argue that they are stationary and the world is moving around them and both frames of reference are correct, even if they provide very VERY different viewpoints (such as in the car example)

If I go back to the car analogy I'll answer your questions. Yes, time does appear to stop at the speed of light, but as I said before, if you were in one of these cars you wouldn't notice this - everything else would appear to be stopped! Also with length dilation you'd be infinitely thin to an observer outside your frame of reference.

If you were travelling at 99.9999% the speed of light then to an observer outside of your frame of reference then the light would overtake your car by 0.0001% the speed of light. But the driver of the car would see the light travelling away from him/her at 100% the speed of light. The point with this analogy is that is seems so very counter intuitive, but stands up to reason and the maths.

Relativity requires you to throw away the concept of an absolute frame of reference and an absolute outcome to a situation, as it often depends on where you are standing.

Hope that clears it up.
Wait so hang on, are you saying that to the person going at 99.9999% of the speed of light, everything is also really slow? I thought that person would perceive everything else moving incredibly quickly. I think I got this idea from reading somewhere that if an astronaut travelled on a fast rocket or spacecraft, they would be return to earth slightly younger than a twin or other person born at the exact same time. Doesn't this mean that the person going near the speed of light has actually experienced less time in the same 'time' and therefore sees everything as moving faster?

However, if this were true, you could ascertain whether an object is moving faster or slower than you by observing whether their time moved faster or slower than yours did, and thus get closer and closer to ascertaining what a true stationary object would be. Which seems wrong...
12. Re: Special Relativity - Einstein's wrong???
Thanks for all the advice. Will create another simulation when viewed from inside the box soon.
13. Re: Special Relativity - Einstein's wrong???
So Neutrinos travel faster than light which could break Einstein's theory. If this neutrinos are really travelling faster then there would be a break-through.