RE: Ultra Massive Black Holes......
February 10, 2019 at 11:32 pm
(This post was last modified: February 10, 2019 at 11:34 pm by Anomalocaris.)
(February 10, 2019 at 4:18 pm)polymath257 Wrote:(February 10, 2019 at 2:10 pm)Anomalocaris Wrote: Yes, but the black star hypothesis also counts as a (still) plausible alternative explanation for observations, so it satisfy as a legitimate reason why actual black holes MIGHT not exist.
OK, I took a closer look at the reasoning for 'black stars'. As far as I can see, the distinction between them and 'true' black holes is that they do not have singularities or event horizons. Instead, they are 'frozen' at what would be the event horizon boundary. This, by the way, is expected to happen in the formation of a black hole because of observer effects concerning time dilation near an event horizon.
Again, truthfully, the difference seems minimal. We expect BHs to form via collapse and thereby be subject to the observer effect. From the view of a distant observer, they will *look* like a black star. Since, from the view of a distant observer, there will *always* be matter outside of the event horizon and since the infall takes an infinite amount of time, there is no real difference between a BH and a black star. This is doubly true if the EH and singularity are 'smoothed over' due to quantum effects.
As far as I can see, this is a distinction without an observable difference, which means there is no difference at all.
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.
