Hi everyone;

I have 2 questions:

1) How can we estimate temperature of an ideal gas in a disk with mass M ,as it is being swallowed by a blackhole?

2) can we assume the gas as a black body? if not so how it is possible to calculate the energy emitted by the gas?

Pre thanks for your answers .

1 If the black hole has less than 10,000 solar mass, essentially all the gas and other matter are shreaded to plasma and subatomic particles shortly before entering the event horizon. For much more massive black holes, gas is possible until slightly inside the event horizon, and should behave like gas does on Earth. A wide variety of observations are possible from reference frames other than the location of the gas.
2 No idea. Neil

Porkav,
Stephan-Bolzman Law?

Radiation in watts/m^2 (per unit time)= Temperature in Kelvins^4 x Stephan-Bolzman constant

This is in the third page down of the Wikipedia entry about Black Bodies.
But I'm afarid you'll have to do the rest of the work yourself!
As I don't know what vaalue the constant has!

JOhn

Is this right ?
Released Gravitational Potential Energy =GM^2 ( (1/r) - (1/R) ) = E
A chane in the internal energy of the ideal gas = 3Nk∆T/2 = U
U = E >>>> Temperature will be found .

( I’m not sure that total released gravitational potential energy will be changed to internal enegy of the gas , because we have radiation as well. )

Where
k is the Boltzmann constant, 1.381x10^-23J/K
N is the number of particles
R is the initial radious of the disk
r is the final radious of the disk

No.

Insufficient information to accurately draw a conclusion regarding temperature of gasses being drawn into a black hole or crossing that event horrison... We know very little of the state of matter in this plasma and energy field. Assumptions are made of the actual conditions we know little of. Where massive gravity does some very strange things....