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What happens when your spaceship is longer than the universe

  1. Aug 28, 2015 #1
    So, as I understand special relativity, when you go close to the speed of light, observers see you "shrink" in the direction of motion, and you see objects as shorter than they were when you were in the same frame, according to L=Lo√1-v2/c2.

    So suppose I am nearby earth (in the same reference frame) and my spaceship measures 1 km long, and earth observers agree. Then I get to a terrific velocity, so that earth observers see me as very contracted in the direction of motion, and I see earth as being actually shorter than my 1 km long spaceship in the direction of motion.

    Well then, I suppose I can get to an even higher velocity, so that I measure my ship to be even longer than the milky way in the direction of motion.

    Then finally, what happens if I get to such a terrific velocity that I measure my ship to be longer than the observable universe? What happens then? Is this possible? I suppose it is impossible from a practical sense, but does it contradict something in physics? Is it allowed to happen?
  2. jcsd
  3. Aug 28, 2015 #2


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