On the Existence of Black Holes:

[beecee]

Recently in another thread on Philosophy, I had cause to question  a claim made that BH's have been shown not to exist. Reasons were because Hawking Radiation had not been discovered and the Information/Firewall paradox. I replied how whether HR existed or not and irrespective of any information paradox, that BH's were well supported by evidence to exist and that the claims made were wrong and invalid.

The person who denied their existence I'm sure was not really attuned to the history of BH's or any of the facts, and probably had only heard/read about them in a few pop science coverages in the daily media. His mispelling of Stephen Hawking's name as Hawkins lead me to that belief, and was certainly not any act of superior knowledge of BH's on my part.

After thinking I then remembered a pop science news item that was widely published a few years ago with regards to a paper by Professor Hawking in which he now believed that BH's did not exist. I was involved in a lengthy debate on this rather surprising revelation on another forum, and it was revealed for what it was...a sensationalist view by the media. The following article details that "out of context"claim. https://www.pbs.org/newshour/science/hawking-meant-black-holes What Hawking meant when he said ‘there are no black holes’

extract from article.....“The absence of event horizons means that there are no black holes — in the sense of regimes from which light can’t escape to infinity,” Hawking wrote in his paper.

"There was also a paper which was discussed by a  Laura Mersini- Houghton     from the University of North Carolina, who claimed she had mathematical proof that BH's did not exist and published in arXiv but not peer reviewed. This paper was subsequently  criticised and invalidated....https://briankoberlein.com/2014/09/25/yes-virginia-black-holes/ Recent headlines have proclaimed “Black Holes Don’t Exist!” They’re wrong. Black holes absolutely exist. We know this observationally. We know by the orbits of stars in the center of our galaxy that there is a supermassive black hole in its center. We know of binary black hole systems. We’ve found the infrared signatures of more than a million black holes. We know of stellar mass black holes, and intermediate mass black holes. We can even see a gas cloud ripped apart by the intense gravity of a black hole. And we can take images of black holes, such as the one above. Yes, Virginia, there are black holes".

<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>

The evidence for BH's has obviously been increased dramatically over the last few years with the discoveries of 5 BH pairs in the act of merging via their gravitational Radiation. While certainly indirect observation, by its very nature, BH's can never be directly observed. The first BH discovered was Cygnus- X1 and as with all known BH's, are evidenced by the effects they have on the matter energy and spacetime within their vicinity. If we are to deny BH existence, we would need something even more extraordinary and counter intuitive  to explain these effects we observe. The gravitational waves discovered by aLIGO and VIRGO matched templates that pointed to these 5 discoveries, their masses, and distances from Earth.

Worth noting at this time also, that actually BH's of sorts was theorised as long ago as the late 1700's by a bloke called John Michell and were called "Dark Stars" being simply a Newtonian explanation, and with the Schwarzchild limit and compulsory collapse unknown.

Edited November 15, 2018 by beecee

[beecee]

Obviously, if there is anything I have misinterpreted above, corrections from our online experts are welcome. Much is from a memory that sometimes needs re-tuning.