On 1/14/2018 8:24 AM, Lawrence Crowell wrote:
On Sunday, January 14, 2018 at 9:25:40 AM UTC-6, John Clark wrote:
On Sun, Jan 14, 2018 at 1:40 AM, Brent Meeker <meek...@verizon.net
<javascript:>>wrote:
>>
I think that would be true if, as in your example, the
observer were freely falling into the Black Hole, but if I
was hovering just outside the Event Horizon in a super
powerful spaceship I could observe the Black Hole
evaporating in just a few minutes
>
That seems doubtful since Hawking radiation has its peak
wavelength on the order of the diameter of the black hole and
originates in the vicinity, i.e. within a few radii of the
black hole, not "at the event horizon".
Most Hawking radiation originates where the tidal forces are the
greatest, and that would be at the Event Horizon. The closer I
hover above the Event Horizon the slower my clock will tick, so if
I hover close enough I can watch the entire Black Hole evaporate
away in just a few minutes by my clock even though for you back on
Earth that would take a billion trillion years or so. The thing
that causes Black Hole evaporation is Hawking radiation, so if I
observe one I'm going to have to observe the other, although
"observe" may not be the right word, "incinerate" might be better.
John K Clark
Where the Hawking occurs is a tad funny. For a distant observer the
radiation will appear to occur at about 4GM/c^2 from the horizon that
has a radius of 2GM/c^2. This does correspond to the wavelength of the
radiation and so forth. However, if you are on an accelerated frame
stationary with respect to the horizon the radiation occurs closer to
the horzion. In the limit you reach Planck acceleration ~ 10^{51}m/s^2
the radiation occurs a Planck length above the horizon. So what is
going on?
So how do you see it if you're free-falling in? Do you see it as blue
shifted as you approach the BH at increasing speed, but it diminishes in
the region between 4GM/c^2 and 2GM/c^2 as you fall toward the event horizon?
Brent
If you observe an object fall towards a black hole it will by the
tortoise coordinate appear to hover just above the horizon. Conversely
the quantum fields and ultimately quantum bits from that object will
appear outside the black hole. In effect they appear at two places at
the same time! What we think of as an event in spacetime as a unique
specifier of the state of a system is an approximation. With quantum
field theory there has been a lot of stuff to remove nonlocality, such
as Wightman conditions of commutators of observables. Quantum
nonlocality plays a subtle role and in high energy experimental
physics its physical influence is considered negligible. However, the
time dilation physics of a black hole amplifies these nonlocal
influences so they can no longer be ignored.
LC
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