On 4/11/2022 12:47 AM, smitra wrote:
On 11-04-2022 09:19, Bruce Kellett wrote:
On Mon, Apr 11, 2022 at 3:58 PM smitra <smi...@zonnet.nl> wrote:
On 10-04-2022 06:15, Bruce Kellett wrote:
Not relevant, since there is no enclosing reflecting boundary.
Yes there is.
Where is it then?
One can also consider an observation inside the event
horizon of a supermassive black hole. No photons escape from there.
We are not currently inside a supermassive black hole. Besides, you
knowledge of BH physics seems somewhat faulty. Inside the horizon, all
particles move towards the singularity at r = 0 (because that is the
forward direction of time). So there is no reflection off the inside
of the horizon. That is a fanciful (and wrong) idea.
The escaping Hawking radiation is so small that it doesn't contain
much
information.
And since you are attempting to promote a FAPP argument to an in
principle argument, you also have to consider that the space
environment
is not a perfect vacuum, so photons do not travel at exactly the
speed
of light. This means that in principle one can retrieve the escaping
photons
I don;t think the difference between c, the speed of light in a
vacuum, and the speed of light in outer space is a relevant
consideration -- you still are not going to catch and reverse those IR
photons.
That's all FAPP, not in principle. The laws of physics are reversible,
it requires a rigorous argument from the fundamental laws of physics
to demonstrate that reversing a measurement is impossible. Arguing
from a practical situation and pointing to immense difficulties is a
FAPP argument.
You seem to think the purpose of physics is to study the consequences of
equations. If something is impossible to observe, I think the purpose
of physics is to explain why it's impossible.
Brent
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