How many different types of Black holes are there?

and can different types of black holes effect the shape of a galaxy?

CrazyNeutrino said:

How many different types of Black holes are there? and can different types of black holes effect the shape of a galaxy?

Please be aware that most of this is theoretical.

There are different ways to classify black holes. A black hole has mass, spin, charge and growth rate/energy output, so could be classified on any of the four.
A charged black hole is known as a Reissner-Nordström black hole.
A rotating black hole is known as a Kerr black hole.
A black hole that is nether charged nor rotating is known as a Schwarzschild black hole
An extreme type of Kerr black hole is the Naked Singularity, in which the event horizon disappears.
Even more extreme is a White Hole where nothing can fall in but things can fall out.
A wormhole, also known as an Einstein–Rosen bridge, is a black hole that connects to a white hole.
One version of the wormhole is a “traversable wormhole stabilised by exotic matter”.

Now let’s classify black holes using mass and size.

A supermassive, or galactic, black hole has a mass of the order of hundreds of thousands to billions of solar masses
An intermediate mass black hole has a mass mass in the range 100 to one million solar masses
A stellar black hole, or stellar mass black hole, has a mass ranging from about 5 to several tens of solar masses
A micro black hole, also called quantum mechanical black hole or mini black hole, can have a mass down to the Planck mass, about 22 micrograms. The presence of large extra dimensions (in String theory) can lower this minimum mass down to of order 10^-20 grams.

A primordial black hole, created in the Big Bang, could have a mass intermediate between micro and stellar black holes, for example from 10^14 to 10^23 kg. Compare the mass of the Earth at 6*10^24 kg.

Then we can classify black holes by luminosity.
An active galactic nucleus (AGN) of a Seifert Galaxy
A Quasar
A Blazar, also known as a BL Lacertae object

Then there are events that spawn black holes, in particular
Supernova
Hypernova
Gamma Ray Burster
Collapse of an object made of dark matter

Is that enough different types?

> can different types of black holes effect the shape of a galaxy?

It’s more likely the other way around. The size of a black hole tends to be correlated to the size of the galactic hub, so elliptical galaxies tend to have bigger central black holes than spiral ones, but it’s much more likely the case that the shape of the galaxy affects the size and spin of the black hole.

mollwollfumble said:

CrazyNeutrino said:

How many different types of Black holes are there? and can different types of black holes effect the shape of a galaxy?

Please be aware that most of this is theoretical.

There are different ways to classify black holes. A black hole has mass, spin, charge and growth rate/energy output, so could be classified on any of the four.
A charged black hole is known as a Reissner-Nordström black hole.
A rotating black hole is known as a Kerr black hole.
A black hole that is nether charged nor rotating is known as a Schwarzschild black hole
An extreme type of Kerr black hole is the Naked Singularity, in which the event horizon disappears.
Even more extreme is a White Hole where nothing can fall in but things can fall out.
A wormhole, also known as an Einstein–Rosen bridge, is a black hole that connects to a white hole.
One version of the wormhole is a “traversable wormhole stabilised by exotic matter”.

Now let’s classify black holes using mass and size.

A supermassive, or galactic, black hole has a mass of the order of hundreds of thousands to billions of solar masses
An intermediate mass black hole has a mass mass in the range 100 to one million solar masses
A stellar black hole, or stellar mass black hole, has a mass ranging from about 5 to several tens of solar masses
A micro black hole, also called quantum mechanical black hole or mini black hole, can have a mass down to the Planck mass, about 22 micrograms. The presence of large extra dimensions (in String theory) can lower this minimum mass down to of order 10^-20 grams.

A primordial black hole, created in the Big Bang, could have a mass intermediate between micro and stellar black holes, for example from 10^14 to 10^23 kg. Compare the mass of the Earth at 6*10^24 kg.

Then we can classify black holes by luminosity.
An active galactic nucleus (AGN) of a Seifert Galaxy
A Quasar
A Blazar, also known as a BL Lacertae object

Then there are events that spawn black holes, in particular
Supernova
Hypernova
Gamma Ray Burster
Collapse of an object made of dark matter

Is that enough different types?

> can different types of black holes effect the shape of a galaxy?

It’s more likely the other way around. The size of a black hole tends to be correlated to the size of the galactic hub, so elliptical galaxies tend to have bigger central black holes than spiral ones, but it’s much more likely the case that the shape of the galaxy affects the size and spin of the black hole.

Blackholes were first theoretical (?) and then proof for their existence was found, white holes and worm holes are currently only theoretical but physics seems to allow them. Shouldn’t we have found proof of white holes by now

> Shouldn’t we have found proof of white holes by now

Only if they exist. But yes, if they existed then we should have seen them by now.

Cymek said:

Blackholes were first theoretical (?) and then proof for their existence was found,

The Schwarzschild black hole was the first solution found to the Einstein field equations of General Relativity, although stars with an escape velocity equal to or exceeding the speed of light under Newtonian gravity had been postulated in 1783 by geologist John Michell. See Dark star (Newtonian mechanics)

FWIW, Schwarzschild found the BH solution in 1915, the same year that Einstein first introduced general relativity. He was serving in the German army at the Russian front at the time, suffering from a horrible painful skin condition, the autoimmune disease pemphigus, which eventually killed him a year later. See Karl Schwarzschild

The evidence that black holes do actually exist is rather good, but the case is not yet proven to everyone’s satisfaction, eg former SSSF astrophysicist Cusp, aka Geraint Lewis is fond of saying that our evidence for dark matter is better than our evidence for black holes.

OTOH, if the astronomical objects that we think are black holes are not actually black holes, then they’re probably something even weirder. :)

The problem is that we (obviously) can’t see black holes themselves, we can only detect them by the effect they have on the matter in their immediate vicinity and on how they bend the path of EM radiation that passes near them. Those effects are purely due to mass concentration, so although we can estimate the masses of these objects we can only roughly estimate the volume they occupy, so we don’t really know that the mass has undergone the kind of collapse predicted by GR.

Cymek said:

white holes and worm holes are currently only theoretical but physics seems to allow them. Shouldn’t we have found proof of white holes by now

White holes have always been more of a fringe theoretical construction. Even Penrose, who is one of the world’s experts on BHs and has done a lot of theoretical work on white holes, is not very hopeful that they actually exist in our universe, and feels that it may be the case that black holes and white holes probably can’t co-exist in the same universe.

There are a few variants of wormhole. Some involve a BH at one end and a WH at the other, but another “flavour” has a BH at each end. The first variety is more interesting in the sense that it’s self-stabilising, although it only permits travel in one direction. The second variety is more likely to be possible in our universe, but unlikely to be stable: even the passage of a single particle could cause the wormhole to collapse, unless it’s stabilised. Unfortunately, it appears that we’d need an exotic form of matter with negative energy density (i.e., negative mass) to stabilise such a wormhole, and it’s highly unlikely that such weird matter can exist in our universe, either naturally or artificially produced.

However, there’s another type of wormhole possible – a kind of flaw in the fabric of spacetime that formed when spacetime itself was created during the BB. If such a spacetime wrinkle exists it will have stretched due to universal expansion, but there’s a good chance that it wouldn’t have stretched uniformly.

And even if there are naturally-occuring worm holes, detecting them is really hard. Even if we had Star Trek style spaceships that could zoom around the galaxy to look for them, we might search for centuries before stumbling across one.

mollwollfumble said:

It’s more likely the other way around. The size of a black hole tends to be correlated to the size of the galactic hub, so elliptical galaxies tend to have bigger central black holes than spiral ones, but it’s much more likely the case that the shape of the galaxy affects the size and spin of the black hole.

The leading theory of elliptical galaxy formation is (still) that they result from the merger of two (or more) spirals; the merging process tends to scramble the neat spiral structure. During the collision the BH cores of the spirals will merge, but as the BHs approach each other they will sweep up a lot of extra mass: gas, dust and stars. So it seems reasonable to me that the BH mass ratio of an elliptical would be higher than that of a spiral, due to all that extra mass they get fed.