# On the idea of time in physics-relativity

Discussion in 'Physics & Math' started by ash64449, Mar 15, 2013.

1. ### ash64449Registered Senior Member

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Your explanation is not right... Einstein is right about his experiment and M&M EXPERIMENT CAN BE BROUGHT FROM SR. I explained it...

3. ### Write4UValued Senior Member

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Likewise in the Doppler effect, the same fundamental physical principles apply.

I understand that we have been able to estimate the actual age (TIME) of the universe through the Doppler effect.

I wonder if, in the lightning example, a red shift of the lightning would take place for the observer in the middle of the train?

from wiki,
What I would like to know, if it is possible for lightning to strike the front and back of a moving train simultaneously at all? It seems to me that they are two separate events each occurring in their own spacetime coordinate. Is this why it is a thought experiment?

5. ### Prof.Laymantotally internally reflectedRegistered Senior Member

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You should answer these questions :

1. Does the M&M experiments say that the beams of light would reach the detector at the same time from its own frame?

2. Does the mind experiment stated by Einstein say that the flashes of light will reach the observer at the same time from the observers own frame?

The answer to the first question is yes, the answer to the secound question is no. Say you did the M&M experiment on a train, the M&M experiment will still find that the answer is yes the observer will measure the beams to reach the same location at the same time. Einsteins thought experiment would still say no. One answer is yes, the other is no, in one they reach the same location at the same time traveling an equal distance and in the other they don't reach the same location at the same time traveling an equal distance.

Now ask yourself something, how would they determine if Einsteins thought experiment was correct? I will give you a hint, they would have to put a M&M experiment on a train!

7. ### ash64449Registered Senior Member

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yes. There is a possibility... that front and the back can hit simultaneously. sorry.no red shift for light in this case..because no effect in the medium is caused( medium for light.. How??!!!:Read the book called Hyperspace for more information about the medium of light). But when the Universe expands, there is an effect in the medium of light.. since stars are moving away,red shift is observed... The reason why in this case there is effect in medium can be understood if you read the Hyperspace book written by Michio Kaku.

8. ### ash64449Registered Senior Member

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Hello you haven't read my posts correctly.. I conducted M&M experiment on the train already.. You didn't read my post clearly.. Please reply only after reading those posts.. Both are same... But in the second,SR experiment needs to be modified.. that is all?? Your answer is right.. first one is yes,second one is no.. But Both are correct!! Figure it out... If you can't,read my previous post.. This is my humble request!!

9. ### Prof.Laymantotally internally reflectedRegistered Senior Member

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I don't know what post you are even talking about. They couldn't possibly both be correct.

10. ### ash64449Registered Senior Member

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""The M&M experiment is just like this(comparing with the train). AN observer in the train which is moving uniformly emits two beams(observer in the middle). An observer outside sees this and observes like this: Two beams move in opposite direction. A beam which is moving parallel to the train at first moves longer distance while other needs to move shorter distance. another two mirrors is kept opposite sides of the train. so the beam which moved parallel to the train go back travelling shorter distance but the other beam needs to travel longer distance. so those two compensate and reach the observer in the train at the same time. But with an observer in the train, he sees beam reach opposite at the same time and reach him at the same time. because it needs to travel same distance in the frame of observer in the train. See opposite of what we were discussing came!!""

This one.. See!! In both references,Light reached the observer in the train at the same time!!! But light beams inside the train,as observed from outside is not simultaneous but simultaneous for observer inside!!! Haven't you seen this post...

11. ### ash64449Registered Senior Member

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This is exactly demanded by relativity.. And c'mon i have explained M&M experiment in the context of relativity too!!

12. ### Prof.Laymantotally internally reflectedRegistered Senior Member

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I looked over it, but it didn't seem to make much sense. It just sounded like you just changed what the mind experiment proposed by Einstein actually said. It clearly states that for an observer on the train that the flashes of light would not reach him at the same time, and that the observer on the station would observe the flashes to reach the center location at the same time. I don't get why you would think that would actually be something different than what it says?

13. ### ash64449Registered Senior Member

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You didn't understand.. Don't you think i have changed the apparatus.. Light beam.. mirrors and all?? and can you see Einstein's experiment is right, but Einstein's experiment is different from that of M&M experiment.. So in order to prove that Einstein's thought experiment is correct,i used another experiment similar to M&M experiment and used what Einstein actually applied.. When i done this: I got M&M experiment!!! That is why i said both are correct.. If you still consider and compare again Eistein's actual thought experiment and M&M experiment,then i say that you don't understand the reference( Co-ordinate system)

14. ### ash64449Registered Senior Member

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In which way it doesn't make a sense?? If Einstein's Thought experiment does,then this one too.. But Einstein's thought experiment does...

15. ### Prof.Laymantotally internally reflectedRegistered Senior Member

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Maybe if you replaced the mirrors and photons with bats and baseballs, then they would both be both correct. But, they are not bats and baseballs, they are mirrors and photons. They don't work the same way, so you can't even really think about it as though it is a baseball getting hit by a bat. The photons will arrive at the same time, they will also be measured to travel at the same speed. I think it is a combination of time dilation and length contraction and simultaniety that makes that possible. It is better to try and acheive the goal from the ends, not reach the goal from the situation. To try and fit the situation to the experiment, not to fit the experiment to the situation.

16. ### ash64449Registered Senior Member

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This is correct!!! At last you arrived at the conclusion... Why did you say those other things.. I know it won't work replacing with baseballs or something!!! And who said like that.. I didn't say anything like that.. So you accept that Einstein's thought experiment is correct??? But the thing is that only time dilation and length contraction.Others work like simultaneity are just consequence of it..

17. ### ash64449Registered Senior Member

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This thread is going somewhere else.. i started with why the observer was placed at the middle and came all the way to here!!

18. ### ash64449Registered Senior Member

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oh.. i think you haven't understood how Eistein's thought experiment lead to time dilation and length contraction.. Should i explain to you?

19. ### Prof.Laymantotally internally reflectedRegistered Senior Member

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Einsteins's thought experiment doesn't conclude that the observer on the train could be in motion and then receive two light beams from opposite ends of the train at the same time! This is not actually what happens in experiments with beams of light. In those experiments the light beam reaches the observer in the middle at the same time! How many times do I have to type this out?

So I don't believe the behavior of photons is as described in the thought experiment, and that it is not actually what happens in actual experiments. Only then could I suffer from delusions of being an actual scientist!

20. ### ash64449Registered Senior Member

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and how many times i have to say that What that you say above is wrong???? Why won't it work.. Because of M&M experiment.....

21. ### ash64449Registered Senior Member

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Is that so because M&M contradicts Einstein's thought experiment????

22. ### Prof.Laymantotally internally reflectedRegistered Senior Member

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Yes, and being a scientist he would have had to have check his theories with actual experiments, it would be the only way he could have been a real scientist. They don't let you have your theories accepeted as science until they are confirmed by actual experiments. That is reason why they do that.

23. ### Prof.Laymantotally internally reflectedRegistered Senior Member

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If you don't want to take my word for it read any other book that explains relativity besides that one.