(February 11, 2019 at 8:46 am)polymath257 Wrote:(February 10, 2019 at 11:32 pm)Anomalocaris Wrote: Time dilation if I am not mistaken only affects free falling towards event horizon. Dark star applies to collapse at less than freefall speeds. Black star in effect suggests that it is possible no true black holes can ever form.
Not true. Time dilation would be significant even if there is no event horizon as long as the gravitational field is large enough. The 'frozen' nature of black stars is precisely this effect.
We expect most black holes to form in situations where there is other matter around. So we expect that there will be matter in a deep gravitational well. It seems that the 'evidence' supporting black stars is that there was a photon signal as well as a gravitational wave signal. But that is expected from BH also because of any extra matter around them.
In essence, a BH with matter around it is exactly the same as a black star from all possible observations. The notions are observationally identical.
This makes a distinction with no difference.
As a sidebar, there was an original Star Trek episode in the 1960s, where Captain Kirk mentions a "black star".
