Special relativity question

In summary, while learning about time dilation, a question was raised in class about the angle of a light ray reflecting off the ceiling of a moving train for an observer outside the train. The teacher confirmed that the observer would see a different spot, but the key is that they would still agree on which atoms the light ray hits. The difference in position is due to the train's deformation, not the actual angle of the light ray.
  • #1
chris2112
20
0
An intersting question was asked in my class today when learning about time dilation. We were shown the classic example of a light ray perpendicular to the floor of a moving train reflecting off the ceiling back to it's source. We were shown the lightray make an angle at the ceiling for an observer outside the train to derive the time dilation. A student asked the teacher to consider a photographic plate right above the ceiling and asked if the ray were to keep going, would the obsever outside the train see a different spot than theobserver inside the train considering the angle. The teacher said yes, they would see different spots, but it doesn't seem right to me. Does the light ray really make an angle to the observer outside the train in reality or is it just a convenient way to derive time dilation?
 
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  • #2
I think the key here is that the observer outside will see the entire train deformed accordingly. So while they do not agree on the position of the beam hitting ceiling, they do agree on which atoms it hits. So they are not "different spots", just the distance measure is different.
 
  • #3
[Edit] Sorry, I deleted my comment and decided to start my own post for it. Although it was about the same subject, the question about it was different. Sorry for intruding your post.
 
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What is special relativity?

Special relativity is a theory developed by Albert Einstein in 1905 to explain the relationship between space and time. It is based on two main principles: the laws of physics are the same for all observers in uniform motion, and the speed of light is constant for all observers regardless of their relative motion.

What is the theory of relativity used for?

The theory of relativity is used to describe the behavior of objects in motion, specifically at high speeds or in strong gravitational fields. It has been confirmed through numerous experiments and is a fundamental part of modern physics.

What is the difference between special relativity and general relativity?

Special relativity deals with the effects of motion on space and time, while general relativity includes the effects of gravity on the curvature of space-time. General relativity is a more comprehensive theory that includes special relativity as a special case.

How does special relativity affect our daily lives?

Special relativity has practical applications in various fields, such as GPS technology and particle accelerators. It also helps us understand the behavior of objects at high speeds, such as the effects of time dilation on astronauts traveling in space.

Is special relativity still considered a valid theory?

Yes, special relativity is still considered a valid theory and has been extensively tested and confirmed through experiments. It is a fundamental part of modern physics and has not been disproven or replaced by any other theory.

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