Black Whirpool.

[Nano]

A black hole is often compared to a whirlpool. Does that mean that in the end, the supermassive BH in the milkyway will suck in all the matter in our galaxy like a vacuum cleaner?

 

The way I see it the black hole is sucking in the closest material at first. New "food" to feed the hole, gets further and further away. Won't it then at some point be to far away for the BH to have any effect on matter, since gravity is weakening 1/4th for each time you double the distance?

 

I don't know if I manage to explain what I mean. My head is not made to think about such big things, but I still find them interesting.

[mulreay]

One theory states that the universe will either end in a big 'crunch' or the universe will just be a vacuum containing nothing but black holes as all the matter is 'devoured' by black holes. You should not concentrate to much on the galaxies central 'massive black hole' as the galaxy will continue to churn out new black holes throughout.

Therefore you could theorise that the black holes would eventually draw themselves in to the centre and add to the 'super massive black' hole present.

 

You could argue that the 'big crunch' and the 'vacuum littered with black holes' are one and the same. As in my humble opinion if all the black holes were to eventually drag in there neighbours and create one 'incredible black hole'. Then this would be the 'crunch' I stated earlier.. whether this would then trigger a new 'big bang' is obviously debatable.

 

My knowledge is limited but my support is sincere.

[Spyman]

I think the comparison to whirlpools is due to that gravity causes matter to spiral inward towards the black hole and create a accretion disc and NOT because black holes suck like vacuum cleaners, which they are not able to do.

 

If the Sun should turn into a black hole then the Earth would continue to orbit as normal, because the formed black hole would have the same mass as the Sun it formed from and therefor also continue to have the same gravitational influence on its surroundings.

 

Similar, if the Sun should be replaced with a star three times as massive as the Sun, this heavier star would pull in the Earth with its stronger gravity in exactly the same manner as a black hole with three times the Suns mass would if it would replace our Sun.

 

Gravity is weakening with larger distance but never goes down to zero or stop effect matter entirely. The Earth is not falling into the Sun because we have orbital speed matching the gravity and distance, likewise since stars in the galaxy are encircling the center, their orbital speed are in balance with the gravity.

 

The process how galaxies and supermassive black holes are formed is not fully known but there are strong indications that they might form and develop together. Some galaxies have a very active core region in the center where a supermassive black hole is turbulently consuming matter but others like the Milky Way have a fairly passive core as if the supermassive black hole there is starved.

 

It's not hard to imagine that a young galaxy or a older one but recently disturbed has plenty of matter for the supermassive black hole in the center to consume, while an older and/or more settled one has less matter left because the black hole has already consumed most of the matter within its reach.

[Nano]

So as long as no other galaxy is interfering with the milky way, the galaxy will after a period of time turn into a lot of smaller black holes orbiting the super massive black hole in the middle. There will still be lots of dust and free gas hanging around, since the black holes doesn't manage to reach all the leftover matter in the galaxy.

 

However it is predicted that the Milky-way and Andromeda is colliding in a few billion years, messing up my "prediction" above.

 

Another thing I was just thinking about. If the dark energy is causing our universe to end in a "big rip", do you think that a black hole would also get ripped apart? I think that it is not so. I don't think a singularity could get torn into peaces, no matter how much energy there is.

[Spyman]

The bigger part of stars won't turn into black holes and the supermassive black hole in the center can contribute to formation of new stars and planets from dust clouds within the galaxy. Most stars will become white dwarfs which much much will later cool and become black dwarfs.

 

 

The merging with Andromeda will cause some disturbance and give us two supermassive black holes that will eventually merge into a large one. But after a few billion years, Andromeda and the Milky Way will have completely merged to form Milkomeda and everything will calm down to normal again.

 

 

If there is true singularities then the Big Bang was likely torn apart from a massive singularity by some cind of force and as such it seems possible that lighter black holes can be torn apart too. But I think the common interpretation of singularities in general relativity is that our mathematical model breaks down and that there are no singularities inside black holes or at the start of the Big Bang. There might be other forces that rules over gravity on very small scales due to quantum mechanics, in this case our Universe could have been formed from a previous contracting Universe in a Big Bounce and the center of black holes would consist of highly compressed matter and energy around a border where quantum gravity are in equilibrium.

 

"One of the main problems with the Big Bang theory is that at the moment of the Big Bang, there is a singularity of zero volume and infinite energy. This is normally interpreted as the end of the physics as we know it; in this case, of the theory of general relativity. This is why one expects quantum effects to become important and avoid the singularity.

 

However, research in loop quantum cosmology purported to show that a previously existing universe collapsed, not to the point of singularity, but to a point before that where the quantum effects of gravity become so strongly repulsive that the universe rebounds back out, forming a new branch. Throughout this collapse and bounce, the evolution is unitary."

http://en.wikipedia.org/wiki/Big_Bounce