On 1/26/2014 8:13 PM, Edgar L. Owen wrote:
PS: A slight correction to one sentence in my post below. The rest is good ....
My sentence "By the time they (the falling objects) are actually beyond the event
horizon they are long gone from view." is ambiguous because it doesn't specify whose
clock time is being referenced. It should be possible for the object to have already
crossed the event horizon in the frame of the event horizon and there still be a faint
image of the object still outside the event horizon on its way back to the external
observer, not to mention the traversal time of the light going all the way back to that
external observer...
Second Brent's statement "..as they red shift towards invisibility" is misleading. The
fading from view is not due to a red shift towards invisibility (though a red shift is
occurring). The red shift is due to the object's increasing velocity deeper into the
gravitational well (which slows the object's comoving clock thus reducing the frequency
of the light it emits),
That's confused. The object's clock, assuming it carries one, doesn't tick slower along
its world line. Physical, i.e. clock, time doesn't "tick" at different rates, it's just
that path lengths may be different between the same two events and the interval between
signals received by distant observers depends on the signal paths.
while the fading is due to fewer photons per unit time reaching the external
observer.
That's true; there is both red shift and apparent slower emission but they are the same
phenomena. I've never seen it analyzed but there is also the possibility of seeing the
object by scattered light (which is the way we see most things). Outside the event
horizon at 3M is the photosphere where photons are caught in circular orbits. I think
they are unstable, so they wouldn't collect there, but there might be a lot between 2M and
3M that are falling in, depending on the nearby illumination sources (e.g. another star).
So there might be a lot of photons reflected off an object as it falls in.
Brent
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