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What do you see at light speed?

  1. Feb 25, 2005 #1
    Maybe this has been answered before, but when you approach the speed of light what do you see out of your eyes in your frame of reference. Now I have seen websites with animations of what it looks like when you approach c, but I don't understand how you can see what you see like that. I think of when you speed up that everything goes by you really fast and it goes behind you or it moves away from you according to your direction of travel. Why do you see all these distortions and slowing down objects when you are traveling at light speed. I mean if you can go 186,000 miles/per sec. than you would be away from the earth in a instant, so why do you still see things around you from earth?
  2. jcsd
  3. Feb 25, 2005 #2


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    If you were travelling near light speed, you would indeed see the entire earth go by "in a flash". You'd need a (very!) high-speed camera that you could watch in slow motion in order to see (in retrospect) what had happened while you were flying by.

    If your camera could capture a million frames per second, you'd move almost 1000 ft between frames (even more if you had significant time dilation) if you were moving at near light velocity.

    The mathetmatics of what you would see if you had the capability to watch it in such "slow motion" has been discussed here in the past, but i'm not sure if you want to get into that much detail. If you do, search physicsforum (and the WWW) for the phrase "Terrell rotation". The physicsforum search can be accessed from the toolbar near the top of the page.
  4. Feb 25, 2005 #3


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    The question of what you would see at light speed isn't really meaningful, because on object travelling at light speed doesn't have a reference frame of its own, and a clock which approaches light speed will get arbitrarily close to being completely frozen in our frame, with the distance between any two points on its journey getting arbitrarily close to zero in its frame (so from its point of view, the time to cross between any two landmarks at a given distance apart in our frame, like our galaxy and the Andromeda galaxy, will approach zero). But for some good visualizations of what things would look like as you travel at some large fraction of light speed, check out this page:


    Also see What would a relativistic interstellar traveller see?
  5. Feb 26, 2005 #4
    It depends on what you're looking at of course. I forgot how things actually "look" outside the window. Objects appear rotated/distorted as I recall. Look up the term "Terell rotation" and see what you get.

  6. Mar 17, 2005 #5

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  7. Mar 18, 2005 #6

    The distortions happen because lengths get contracted only in the
    direction you are moving, not to the sides. If you squeeze one space
    coordinate but not the other two, you tend to "pancake" what you would
    otherwise see.

    Also, time is being affected but for all directions, not just the forward one.

    This is one of those case were the equations should be studied until
    they make complete physical sense. (Don't try that with a quantum
    Psi function...)
  8. Mar 19, 2005 #7


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    Only objects which have a high relative velocity to your space ship will appear distorted. The objects traveling with you or those with a small relative velocity will be unaffected by your speed.
  9. Mar 23, 2005 #8
    if v = c then L = 0 which means you won't see anything, and nothing can see you.
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