New answers tagged general-relativity
2
Let's answer the question from the point of view of a stable neutron star.
The luminosity is
$$L_0 = 4\pi R_0^2 \sigma T_{0}^4$$
in the inertial frame of the neutron star surface (assume a non-spinning object).
For a distant observer, the radius of the neutron star is (e.g. see Haensel 2001)
$$R_{\infty}= R_0 \left(1 - R_s/R_0\right)^{-1/2}\, ,$$
the ...
4
I am sorry to say, but the best resources are still books. If it is really a no-go, read further. It is very likely, that you can find and buy astronomy books on Arabic on the Internet. First start with popular science books. Buy multiple books. To learn something, books are still somehow far better than the Internet.
Check the Arabic wikipedia, like this ...
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