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Might Have Solved My Own Paradox

  1. Feb 15, 2009 #1
    I'm new, and basically just study physics as a hobby. I've yet to understand the mathematics, just the concepts. In studying spacetime contraction, I led myself to a paradox, which would leave someone both dead and alive. Let me explain.

    Say you were on a spaceship that could travel at light speed, and were going to one of the outer planets, or even further. Relative to you, spacetime has contracted to 0, and as a result, information along the trip was never part of the journey. Once you reach sub-luminous speed, you would begin recieving information again.

    Lets say that along the trip, your ship has an unfortunate encounter in the asteroid belt, and is destroyed. However, it would only be destroyed relative to a sub-luminous object, which sees your ship experience time, and impact the meteor. The result is an inconsistency in the information. Relative to you, you arrive at your destination unscathed, because the information about hitting the asteroid never reached you. However, relative to a sub-luminous observer, you died in the collision.

    Here's the conclusion I came to-

    Each object has it's own light cone. As soon as spacetime contracts, your light cone slows down, and at light speed, it stops. So during this trip, as soon as you reduce to sub-luminous speed, your light cone continues where it left off (the moment exactly when you hit light speed), and sometime in the future section of the cone, lurks the information about the collision. You basically become a ticking time bomb. And one day, you and your ship will spontaneously explode in the exact same manner as in the explosion in the belt, as the information about the collision passes from the future cone to the present point.

    So what do you guys think? Be gentle, remember, this is just my hobby.
  2. jcsd
  3. Feb 15, 2009 #2


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    In relativity, things that happen at each point in spacetime are called "events" and are absolute. These include light being reflected off a mirror or you being struck by lightning. The numbers or coordinates that different observers assign to events are relative. The point of relativity is that if we know how one observer assigns her numbers, we also know how another observer assigns his different numbers.
  4. Feb 16, 2009 #3
    The "inconsistency" is that different observers see things differently in relativity...they do NOT agree on times and lengths and simultaneaity. It's 'relativity of simultaneity".

    It's not really "an inconsistency in the information" but one of interpretation.

    Try reading about the "pole in the barn paradox"....

    Another way to consider your problem would be to note that most of the universe is never even aware of your existence... or demise....those observers are beyond your cosmological horizon....
    is this an "inconsistency"? (not to me.) Classical forms of logic don't hold so well in cosmological/relativistic frameworks....what that means is we need to force ourselves to think differently..sometime radically so.
  5. Feb 18, 2009 #4
    Hi 3ckpilot I don't think about these matters anymore I KNOW.
    If you recede me with light velocity, whether that is a fact or only a thought experiment, I still receive light from you but the occurences proceed at halftime. I look at a video 50% time zoomed. So you are not vanished from my super Hubble scope and if you encounter a astroid deadly I see you dy only at slowmotion factor half. If you encircle the astroids which I hope then I see that also at half speed and to compensate I enjoy that at double speed. I don't see any paradox or seemingly contradiction and happily don't believe in paradoxes as if explicit contradictions would be anything other then checkmate, stop and try another game.
  6. Feb 18, 2009 #5


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    Time for you to do some thinking again. Most of what you say is factually wrong.
  7. Feb 18, 2009 #6


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    Massive objects cannot travel at the speed of light so I guess I would say the question itself is ill-posed. Your understanding of light cones appears to incorrect too. I would say keep reading and try and learn the math - it's been my experience that once you have equations to back things up they make a lot more sense. Good luck and stay curious!
  8. Feb 18, 2009 #7
    I know that massive objects can't travel as the speed of light, I thought it might just be interesting to think about what it might be like. :p

    So what exactly is the maximum speed of information? 186,000MPS?

    I kind of thought of the light cone as an "information cone", not just a light cone. From the present point, information about the future becomes more vague due to the branching of wave functions, and past information becomes more vague because it becomes useless (the present information is an "updated" version of the past information). It's my own little idea, and I guess it needs a bit of refining.
    Last edited: Feb 18, 2009
  9. Feb 22, 2009 #8
    Nice your definition of information cone. For the maximum velocity of information there is the interesting "Paris splitting experiment" of an Atom with two paired electrons up-spin or down-spin which go in opposite directions with high velocity say 0,7*c. On one side the electrons are detected and knowledge of the spin (up or down) gives information about the electron on the other side. This is proof for superliminous information velocity.
    I must add that you do not drag your information cone with you only of the very recent spheres you stand in the centre. I use to explain that with movement of water by ducks.
    At everery moment circular movement of water is created but when the ducks move you get this v-shaped wake...
  10. Feb 22, 2009 #9
    Entanglement can not be used to send information faster then light.
    It is discussed in the Quantummechanics subforum 1000 times (but still new thread about it are opened at least once a week)
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