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Thread: Static Light...

  1. #1 Static Light... 
    Forum Freshman IrishStu's Avatar
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    I'll try to explain where I'm coming from as clearly as possible because I'm not quite sure how to explain it myself .

    Imagine for a minute that the speed of light is 50mph. You're driving your pickup traveling at 50mph(c). Your friend, in the back, starts throwing tennis balls (photons) out the back at 50mph(c). To a stationary observer on the side of the road, these balls would appear to just drop to the ground as soon as they were let go by your friend. They would not appear to travel forward or backwards in relation to the pickup, they would just drop in a straight line since the two directions of travel cancel each other out.

    Now apply this to space. A ship, traveling at 186,000mps generating light from it's engine (leaving the engine at c). Would the two oppisite velocities (forward travel of the ship and the reverse travel of the light from the engine) cancel, making the photons "hang" (be motionless) in space??? Could light maintain it's properties if it were static? If not then would this mean that light has the potential to travel in any direction without it being deflected by a physical object?

    I know that it's theorized that photons can get "stuck" at the event horizon of a blackhole, making them apperar to "hang". But this involves massive gravitational field's.


    Am I making any sense???


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  3. #2  
    Forum Ph.D.
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    Someone correct me if I'm wrong, but the first thing that seemed off to me was this:

    To a stationary observer on the side of the road, these balls would appear to just drop to the ground as soon as they were let go by your friend.
    The speed of light is the speed of light, regardless of your reference frame. If someone comes out the back of something at the speed of light, they don't "cancel" each other out like you are suggesting. A side of the road observer would see the tennis ball come out at the speed of light


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  4. #3  
    JS
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    Neutrino is perfectly correct. The other point is that no two intertial observers can ever move with the speed of light (in vacuum) relative to each other. They can get arbitrarily close, but they'll never quite get there.
    And God said: Div(E) = \rho / \epsilon_0, Curl(E) = - \partial(B,t), Div(B) = 0, Curl(B) = \mu_0 (j + \epsilon_0 \partial(E,t)). And there was light.

    [...]

    And thus God sent forth Man from the Garden of Eden after a heated discussion of dresscodes and eating habits.
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  5. #4  
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    I think this is very hard to explain. But I imagine we could have the guy just drop the tennis ball as he stands on the road in front of you. But since we're all moving, he could have dropped the ball in the truck and if you were in the truck also it would just fall to the floor. So if he dropped a photon we would have to be moving at the speed of light also. Time would be stopped, nothing would be happening, it's probably a none event or something. At a bit slower than the speed of light there is all sorts of distortions I'm not sure how to explain. A photon doesn't exist except at the speed of light, it has only motion, no mass.
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  6. #5  
    JS
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    1) An emitter must be inertial, and so cannot move at the speed of light.

    2) Light (in vacuum) moves at c in all frames. So if a spaceship moving at any velocity relative to a planet emitted an omnidirectional flash of light, the light front would form a sphere moving outwards at c. The sphere would be centred on the spaceship when measured from the ship's frame, and would be centred on the point in space that the spaceship occupied at the time of emission if measured in the planet's frame.
    And God said: Div(E) = \rho / \epsilon_0, Curl(E) = - \partial(B,t), Div(B) = 0, Curl(B) = \mu_0 (j + \epsilon_0 \partial(E,t)). And there was light.

    [...]

    And thus God sent forth Man from the Garden of Eden after a heated discussion of dresscodes and eating habits.
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  7. #6  
    Forum Freshman IrishStu's Avatar
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    Thank's for your insight all!
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