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Can we escape a black hole's event horizon using another?

  1. Mar 12, 2014 #1
    I have always assumed once we pass through a black hole's event horizon, we can throw away the return ticket. But I have been thinking - is it really so final?

    Consider two identical black holes close to each other with their even horizons overlapping, or nearly so. Is the spacetime on a plane equidistant from the CG of both and orthogonal to the line joining them flat, with each negating the other's gravity?

    Is there a possibility that someone on this plane could move along that plane and possibly escape from within the event horizon of both (if they overlap)?

    Even if they don't overlap, could one of them negate the effect of the other's gravity sufficiently to allow escape from just inside the event horizon of either?
  2. jcsd
  3. Mar 12, 2014 #2


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    When two event horizons overlap, you have one bigger event horizon and no possibility of escape. You will quickly end up with one bigger, spherical, BH (after a violent merger with a lot of energy released as gravitational waves). Classically, the only loophole for escape from inside a horizon is via wormhole or matter that violates energy conditions (e.g. tachyons).
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