Wormholes and energy conservation

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Pete, May 11, 2006.

  1. Pete It's not rocket surgery Moderator

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    Is anyone here familiar with Kip Thorne's wormholes?

    I was thinking about what a wormhole would look like between (say) Brisbane and London, and it occurred to me that atmosperic pressure difference between the two would cause nasty local weather problems if the hole ends weren't enclosed suitably.

    Then I thought about height difference between the two, and thought "if one end of a wormhole were on top of a mountain, and the other end at the bottom, would it be difficult to climb "up" through the wormhole? If not, then energy conservation is violated.

    So, could wormholes cause the violation of energy conservation, or does gravity propogate through a wormhole in a way that resolves this problem?

    Finally, what about Kinetic Energy?
    If the two ends of the wormhole are moving relative to each other (as Kip Thorne describes when explaining how to make a time machine from a wormhole), then how might energy be conserved when a massive object passes through?
     
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  3. Magic Chicken Registered Senior Member

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    Hi Pete

    Interesting questions - how come they didn't get a run at sssf?

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    First point - energy conservation is maintained locally (in the relativistic sense). The reason for this is that energy is an observer dependent variable, which means conservation is meaningless across different reference frames.

    Second point, paths through wormholes aren't paths through normal space-time.

    Now, given those, what do you mean by conservation of energy between sydney and london?
     
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  5. Pete It's not rocket surgery Moderator

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    Brisbane and London was just lead-in.

    I think the real question might be described like so:

    If one end of a wormhole were directly above the other end, would you have a free energy device? If I dropped something into the bottom wormhole, would it come out the top wormhole with the same speed as it fell into the bottom hole, and then keep falling faster and faster?
     
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  7. Magic Chicken Registered Senior Member

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    >> If I dropped something into the bottom wormhole, would it come out the top wormhole with the same speed as it fell into the bottom hole, and then keep falling faster and faster?

    Something falling in the situaiton you described only appears to gain speed and energy relative to accelerating observers. Freefalling reference frames are inertial, so no work is being done on the object as it completes cycles. It continues moving just as any other inertial object does.
     
  8. Pete It's not rocket surgery Moderator

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    So if we use a wormhole to move water from the bottom of a hydroelectric dam back up to the top, do we get electricity out of our generators or not?
     

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