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Theory Of Relativity's effect on light

  1. May 17, 2012 #1
    Hi, I'm actually really glad to be submitting my own post on PF, and I have always been wondering about how the theory of relativity affects how light travels through time.

    If you look at a person, you will see that the faster they move through space, the slower they move through time (At an exponential rate probably, because you can never reach the speed of light), and as they slow down, their their time rate catches up to static objects. This could probably be shown on a graph.

    Well, if that is true, then what about light? I am pretty sure that light has some sort of mass because it can't escape a black hole because of a large black hole's escape velocity, so I would like to know if it is proven if or if not it affects light.

    When on Earth, light is travelling just under c because it is not in a vacuum, so I wonder why light does not seem distorted for us, since if an object travels at close to the speed of light, we would not see it as it really is.
    And some might probably say that it does not look very much distorted because when we look at normal things, the time it takes for its light reflection to get to us is so little.

    Now, think of the light from the sun that goes to Earth. It is travelling for approximately 8 minutes AT the speed of light for most of the time, since space is a vacuum. I wonder if the affect from the theory of relativity would be really extreme, or if it would stay the same.

    Another way to look at this is how we measure the speed of light. We have a definition for the speed of light, and if light were to travel at extremely close to c, not at it, then it would seem for us that it took a longer time to reach us than it really did. Wouldn't we then not have the correct calculations for the speed of light because of that, if my questions answer is yes?

    Thank you for reading, and I'm sorry for making it a bit too long, I just wanted to get all of my thoughts out straight for you guys to see if there are any definitions, opinions, or other people thinking about it as well.
  2. jcsd
  3. May 17, 2012 #2
    I think all of your problems are coming from one thing which I think you haven't realized you are doing wrong, light can't travel slower than c. c is defined as the speed of light, and one of the two postulates of relativity is that no matter what, light always travels at c. When in materials, light can seem to travel slower than c, but truthfully thats a bulk effect causes by interferences and at no point is light actually traveling less than c.

    Does that clear up your questions?
  4. May 17, 2012 #3
    yes, I understand what you mean by that. Now, I heard that if you have a graph, and you show a point not moving through space, with space being Y and Time being X, your X, and in this case, rate of X will decrease. So, technically, if you are moving through space at the speed of light, then you are not moving through time. So why is light not distorted?
  5. May 17, 2012 #4
    Oh, wait, I think I've got it.
    Maybe if you shot a beam of light with a picture in it, the picture would stay the same as it was when it started travelling from the point of where it was shot from, so the frame stays constant? Though, When if an object was at the speed of light exactly, its time would slow down to 0, and that would mean that it takes us an infinite amount of time to see it, if we are static.
  6. May 17, 2012 #5
    It seems like you are interested in this topic, but are lacking some fundamental concepts that are pretty easy to understand, so before trying to answer you questions I would recommend reading this: http://en.wikipedia.org/wiki/Introduction_to_special_relativity

    If you still have questions after reading that (or another basic introduction to SR), definitely come back and ask them!
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