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Wormholes with a different gravitational potential at each end

  1. Dec 17, 2013 #1
    Hi - I have a question about wormholes, specifically when the two endpoints have a differnt gravitional potential.

    If we imagine the technology extisted to create a person sized wormhole between say the earth and the moon, I think the popular perception would be that one could simply walk through the wormhole on earth and walk out on the moon.

    However there is clearly a big difference in gravitational potential energy between the earth and the moon. A rocket leaving the earth has to expend alot of energy climbing out of the earth's gravitational well, and not much breaking against the moon's gravity when it lands.

    If the wormhole is say one meter long, this difference in potential occurs over the space of meter instead of the 200,000 miles or so of ordinary space. So I would expect their to be massive gradient inside the wormole, which would require a massive force to get something through. Converly if one pushed an object from the earth to the moon it would experience a huge force pushing it down to the earth and presumably smash to bits.

    Is this roughly correct?
  2. jcsd
  3. Dec 18, 2013 #2
    I tend to dismiss the entire concept of 'wormholes', until and if they are found or created. Just because something appears to be possible mathmatically (with all the assumptions and approximations inherent in the math equations), doesn't make it necessarily physically possible. Therefore, any additional bizarre questions about the nature of these imaginary things seems like a waste of time to me. Just my 2c. I'd prefer you think about Trek like transporters... at least these may be possible to build. (search 'Spooky action at a distance' and teleportation)...
  4. Dec 23, 2013 #3
    @RocketSci5KN: "...any additional bizarre questions about the nature of these imaginary things seems like a waste of time to me..."
    You're not thinking like physicists do. It is exceedingly productive to ponder areas of your physical theories that seem to lead to contradictions or make bizarre predictions. This is how Einstein discovered relativity in the first place (by considering the absurd and impossible notion of an observer traveling at the speed of light).

    @patfada: As I understand it, you are correct about there being an extreme potential gradient within the wormhole. Here is an excerpt from a Wormhole FAQ that seems to confirm your insight.

    Is a wormhole whose mouths are arranged vertically in a gravitational field a source of unlimited energy?
    No. The argument in favor of such a wormhole being an energy source is this: An object falls from the upper mouth, gains kinetic energy as it falls, enters the lower mouth, reemerges from the upper mouth with this newly acquired kinetic energy, and repeats the cycle to gain even more kinetic energy ad infinitum. The problem with this is that general relativity does not permit discontinuities in the metric – the descriptor of the geometry of spacetime. This means that the gravitational potential of an object at the lower mouth must continuously rise within the wormhole to match the potential it had at the upper mouth. In other words, this traversal of the wormhole is “uphill” and therefore requires work. This work precisely cancels the gain in kinetic energy.

    I believe that the FAQ comes from a book written by a physicist (The Physics of Stargates -- Parallel Universes, Time Travel, and the Enigma of Wormhole Physics by Enrico Rodrigo)
  5. Dec 23, 2013 #4
    Thank you. Well said.

    I would tend to say something less helpful like "Don't the wormhole people have a wormhole site they can go to?"
  6. Dec 23, 2013 #5


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    This topic is too speculative for this forum.

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