I suppose that in there, in the dead middle centre, there is one atom of some sort and its density is not infinite. If not, in there is an yet unknown "thing"...
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Oh wait, now I recall an old argument FOR there being a singularity in there - since you can't see past the event horizon, it's "OKAY" that it breaks laws, has infinite density, etc., as you'll never see it and you'll never know about it!
R.P. Kerr, he of rotating black hole fame, says the consensus view for sixty years has been that all black holes have singularities.
However, he further says that it has not been proved that a singularity is inevitable when an event horizon forms around a collapsing star.
https://www.researchgate.net/publication/375744216_Do_Black_Holes_have_Singularities
I take it that his ring singularities (or ringularities) only exist by way of incomplete mathematical theorums.
However, he further says that it has not been proved that a singularity is inevitable when an event horizon forms around a collapsing star.
https://www.researchgate.net/publication/375744216_Do_Black_Holes_have_Singularities
I take it that his ring singularities (or ringularities) only exist by way of incomplete mathematical theorums.
I've always had doubt about black holes of any sort. You might say Einstein physics breaks down. Who knows? Some one does some sums using those and says it can happen. The idea that matter can have very high densities isn't new. Certain type of stars. All more or less determined by orbits and gravity. Resolving the objects - we can't. They are still dots.
I posted a link to a Max Plank Institute report. We can to some extent look at the core of our galaxy as there are gaps in the dust. They used one and found a red giant and wonder how that can happen if a black hole is there. Also pointing out that behaviour depends on what is there which could just be a load of stars. I also came a across a Hubble image. They looked at an area thought to have a black hole and could resolve stars. It used time lapse to look at movement and saw lots and lots of stars in some sort of orbit. Results questioned, doubt wise and I can now find no trace of it. Maybe some one created it for a joke.
Singularities give rise to several infinities. End of story as far as I am concerned. More likely to indicate they can't exist /totally beyond any physics we are aware of.
Then of course the universe isn't behaving as expect so a couple of dark things are needed.
I posted a link to a Max Plank Institute report. We can to some extent look at the core of our galaxy as there are gaps in the dust. They used one and found a red giant and wonder how that can happen if a black hole is there. Also pointing out that behaviour depends on what is there which could just be a load of stars. I also came a across a Hubble image. They looked at an area thought to have a black hole and could resolve stars. It used time lapse to look at movement and saw lots and lots of stars in some sort of orbit. Results questioned, doubt wise and I can now find no trace of it. Maybe some one created it for a joke.
Singularities give rise to several infinities. End of story as far as I am concerned. More likely to indicate they can't exist /totally beyond any physics we are aware of.
Then of course the universe isn't behaving as expect so a couple of dark things are needed.
The reason the center of most galaxies emits an enormous amount of light is because the supermassive black hole in the center of the galaxy brings into its event horizon super high-speed glasses and debris causing them to heat up to extremely high temps and radiate light of great luminosity, if that‘s the right word. When I say supermassive I mean on the order of millions of solar masses and sometimes billions of solar masses. A red giant can be likened unto a gnat on a bear’s behind.
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We know there is a supermassive black hole (Sagittarious A*) at the centre of our galaxy because we can see stars orbiting around it.
For example, star S2 is on a 16-year elliptical orbit around the black hole: https://en.wikipedia.org/wiki/S2_(star)
Below is an image showing the movement of S2 in its orbit from 1992 to 2002.
And here is a "time lapse" video:
Have a read about Sag.. and what it is - also the number of OB stars spotted. Short lived types.
https://en.wikipedia.org/wiki/Sagittarius_A
I mostly wonder about black holes actual nature and if they can exist in that form. Also the point the Max Plank lot made. Orbits are down to gravity which works in all directions and if you can't see what is there all sorts of things are possible. In general we can not resolve galaxial centres, The density of stars is too high,
Just to be clear to readers, the link you have provided is related to Sagittarius A, a complex radio source that lies at the centre of our galaxy.
The link includes mention of the supermassive black hole, known as Sagittarious A*, the location of which is arrowed in the above image
Here is a more comprehensive link to SgrA* itself: https://en.wikipedia.org/wiki/Sagittarius_A*
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It’s possible for very large stars to exist in - cosmologically speaking - close proximity to black holes provided they are in orbit around the black hole. Of course, if they stray too close, they get eaten, but we can say the same thing about a planet orbiting a star. Some of the stars around Sag* are moving at 10’s of million of km/h
You'll see mention of the "Snake" and the "Mouse" on the above Sagittarious A radio map (post #2,912).
The MeerKAT radio telescope array has revealed hitherto unseen details of these features at the centre of our galaxy.
The image shows a supernova remnant at the centre, to the left of which is a feature known as the "Mouse", which is believed to be a pulsar ejected by the supernova remnant. To the upper right is one of the longest radio filaments, known as "The Snake".
The MeerKAT radio telescope array has revealed hitherto unseen details of these features at the centre of our galaxy.
The image shows a supernova remnant at the centre, to the left of which is a feature known as the "Mouse", which is believed to be a pulsar ejected by the supernova remnant. To the upper right is one of the longest radio filaments, known as "The Snake".
Indeed, star S2 has the fastest ballistic orbit yet measured, travelling at almost 3% of the speed of light at its closest approach to SgrA*.
The image in some respects relate to quasars. A famous one NRAO 530. Brief page on it
https://phys.org/news/2023-02-event-horizon-telescope-captures-images.html
There is a link to a paper on that page that gets more complicated as it's been studied for some time at all sorts of wavelengths. The wiki page on the EHT includes broad idea of the estimated mass of the black hole. A range of possibilities as not enough info.
Some sources say it is a black hole as these are envisaged some say thought to be. Max Plank lot pointing out that gravity, mass and orbits are related and that if unable to observe it's rather hard to determine what that mass actually is.
https://phys.org/news/2023-02-event-horizon-telescope-captures-images.html
There is a link to a paper on that page that gets more complicated as it's been studied for some time at all sorts of wavelengths. The wiki page on the EHT includes broad idea of the estimated mass of the black hole. A range of possibilities as not enough info.
Some sources say it is a black hole as these are envisaged some say thought to be. Max Plank lot pointing out that gravity, mass and orbits are related and that if unable to observe it's rather hard to determine what that mass actually is.
So if you go over the first event horizon in a very large Kerr black hole, it seems to me you could survive and that you'd orbit the inner event horizon per the simulations essentially forever? What happens to time? What other relativistic effects may be taking place?
I would expect a galaxy to be rather unstable whilst spinning without a super massive black hole in the center of it. That’s why the black hole is always in the center. Just as a very large heavy spinning top is very stable, unperturbed by small perturbations, compared to a relatively small one. Did we already establish how fast a supermassive black hole spins?
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