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neutralino · Quote #96 (**permalink**) 11-24-2007, 12:52 PM

Quote:

Originally Posted by cosvis

Albert Einstein and Max Planck have clearly established that the wavelength of a photon, which has no relativistic or rest mass ...

A photon certainly has no rest mass but, if you choose to discuss its relativistic mass (which I prefer not to, since IMHO it can cause a lot of confusion) you cannot say that it is zero. This can be shown from special relativity on invoking the equation $E=\mu c^2$ , where I've used $\mu$ to denote the relativistic mass. Then, we find that $\mu=\frac{m}{\sqrt(1-v^2/c^2}}$ . I think you probably mean to use the term non-relativistic, or inertial.

Quote:

In a black hole situation, the gravitational pull is so strong that not even radiant energy can escape. This radius is known as the Schwarzschield radius and it will increase as its mass or energy is increased.

I have a pedantic but, IMHO important point to make here: one can only say that the event horizon for a black hole coincides with the Schwarzschild radius for a non-rotating black hole; i.e. a Schwarzschild black hole. Then it is true that this radius depends only upon the mass parameter of the black hole ( $r_s=2M$ , using geometric units, c=G=1, with M the Schwarzschild mass parameter.) For rotating black holes, the event horizon also depends upon the angular momentum of the black hole.

Other than that, your post is a good summary.