He didn't believe in black holes either. He thought neutron stars we the densest form of matter. He didn't know photons had mass https://en.wikipedia.org/wiki/Photon. But according to special relativity, light ALWAYS travels with the light speed c, and is NEVER at rest. And so it has zero REST mass. which means that though photons don't have rest mass, they do have energy and thus they have mass. The photons are wave particles.
So a photon has a little mass as does a electron.
This is only important as you pass a brown giant. That is an iron sun – a star that has fused all its helium, and orbits around as a massive zone of gravity – and heavy element: that looks black – and is 1,000 more compact that a red giant.
So photons pass within the gravity field, and are deflected – gravitational lensing. So if we look around 'black holes', we will see multiple images of the stars behind.
So we haven't got a zero size star. They display spin, and without dimension, you can't have cyclical radio emissions.
That's interesting – neither radio waves, X-rays or visible light can escape a black hole. AS professor Hawking pointed out, we get massive X-ray emission from all of the star.
Just like if we had fantastically hot, but not radiant matter.
So spin AND X-ray emission 'What we got here Jim, IS NOT A BLACK HOLE'. The eventual fate of these objects? The in fall of interstellar antimatter, results in the star going nova.
An we have loads of Nova going off – and archived photographs of that region of space, and a gravitational lensing, but non radiant star. Not a black hole.