Quote:
Originally Posted by Robh
Steven,
Interesting debate. I would suggest that the distortion of the event horizon would be a combination of both angular momentum and gravity. In my mind, it is reasonable to assume that two close black holes would create immense mutual gravitational disturbances that would deform the event horizon. After all, it is mass and hence gravity that defines the black hole's event horizon in the first place. The upper diagram in Craig's reference (previous post) indicates this distortion as the two black holes approach each in linear fashion (no orbital physics involved).
Regards, Rob
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Rob,
The event horizon has no physical reality in the black hole's frame of reference. It only exists to an observer outside the horizon. It cannot be distorted by gravity because it doesn't exist to the black hole.
For a nonrotating black hole, it takes an infinite amount of time for an object moving in a radial direction to cross the horizon (hence the term event horizon). If the event horizon is well away from the singularity the tidal forces on the object are small. The object appears to come to a grinding stop at the horizon but remains intact. In the black hole's frame of reference the object is perfectly free to travel towards the singularity to be eventually destroyed by tidal forces.
For a rotating black hole if the object approaches at an angle except along the axis of rotation, the object will appear to spiral towards the flattened horizon. At this horizon it will appear to orbit forever.
However like the nonrotating black hole, the object will actually pass through the horizon along a radial path and be destroyed by tidal forces.
The role of angular momentum as can be seen plays a very unfamiliar part when it come to event horizons.
Regards
Steven