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Naty1
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I am wondering which black hole horizons might be observed experimentally.
a comment in another thread...(PAllen)
Kip Thorne in BLACK HOLES AND TIME WARPS has a nice spacetime diagram for what he calls the absolute (current) and apparent horizons of a black hole.
The apparent or "current" horizon
The apparent horizon appears suddenly (I guess instantaneously) as the surface of a star shrinks past the the critical circumference...and concides with the absolute horizon.
I am wondering if, as the absolute horizon expands, it it observable in any way...say via gravitational waves??
A third type: (apparently 'observable')
Leonard Susskind has a slightly different "stretched horizon" he explains in the BLACK HOLE WAR:
a comment in another thread...(PAllen)
Interestingly, if a planet approaches an event horizon, the horizon grows well before the planet reaches the horizon. The current event horizon reflects (in part) all matter that will eventually be trapped.
Kip Thorne in BLACK HOLES AND TIME WARPS has a nice spacetime diagram for what he calls the absolute (current) and apparent horizons of a black hole.
The apparent or "current" horizon
...is just a point when created...and expands smoothly...before the star's surface shrinks through the critical circumference...
The apparent horizon appears suddenly (I guess instantaneously) as the surface of a star shrinks past the the critical circumference...and concides with the absolute horizon.
I am wondering if, as the absolute horizon expands, it it observable in any way...say via gravitational waves??
A third type: (apparently 'observable')
Leonard Susskind has a slightly different "stretched horizon" he explains in the BLACK HOLE WAR:
...Astrophysicsts has already coined the name stretched horizon for an imaginary membrane just outside the horizon...but I was proposing a real layer of stuff, located a Planck length above the horizon, not an imaginary surface. What's more I claimed that an experiment...say lowering a thermometer and measuring temperature for example, would confirm the existence of horizon atoms...