Black holes & gravitation / mass acceleration

[matt22]

I read that the current theories of the 'end of the universe' is either the big chill or the big crunch. However I was thinking about black holes - that the more mass they gain, the stronger their gravitational pull and if in proximity to other matter, then more mass is gained and the cycle continues. I was wondering if it would be possible for this cycle to get to a stage at which the black hole can suck in entire galaxies and eventually the universe? I assume not or I guess I would have read about it being a possible end of the universe, but why is it not possible? Is it simply because everything in space is too distant for a black hole to ever engulf enough matter? Sorry if it's a stupid question! Thanks!

[Dave_Oblad]

Hi Matt, welcome to the Forums.

Since this is posted in the Beginners area, I won't go into major details.

First point is that Gravity is not a pulling force, so the answer is "NO" there will not be some massive Black Hole sucking up everything.. including other Black Holes.

The presence of Matter Curves Space_Time. Planets and stuff are not pulled towards a Star, but rather material that comes within a Gravitational field of a Star can be captured into falling into an orbit following the Curvature of Space_Time around that Star.

The Black Hole at the center of a Galaxy is not holding all of it's Stars in that Galaxy together.. but rather each Star is following the Curvature of Space-Time created by the whole Galaxy. Stars are too far apart for their own respective Gravity fields to be barely noticeable by neighboring Stars, let alone something as far away as the center of a Galaxy.

Dark Matter is the key to holding everything together but Science doesn't know what Dark Matter is yet. There are several ideas, but none have been confirmed. All we can say is that Dark Matter re-enforces/amplifies the Curvature of Space-Time and leave it at that.

Since the Universe seems to be inflating at an accelerating pace, then the Big-Crunch is very improbable. Ultimately, every Star will burn out and the Galaxies will cease to give off light. New Stars will cease forming when the raw materials are exhausted. This will leave Galaxies filled with dead Stars having dead planets still orbiting them for a very long time. Some Black Holes may hang around for a very long time as well.. or just evaporate over enough time.

So, the Big Chill is the most likely "End of the Universe" scenario.

Note: My personal favorite is the "Completion Scenario" however. The Universe may cease to Exist when it is "Completed" by it's own definition. That could happen at any minute, long before the Stars die, without any warning. I grant it's a very unlikely ending for the Universe but no one can prove it's impossible. There are several other ideas floating around, just as strange as this one. But it's all pure speculation and we should just stick with what Conventional Science predicts, as I described above before my Note.

Hope that helps,
Dave :^)

Ps. I'm just a Science Buff, so perhaps a local Expert may have more to add.

[narnug]

Hey matt22 and Dave

I think this is an interesting issue.

Because you mention dark-matter in this contest Dave I want to ask/consider its "nature".

I have had the feeling that when dark-matter is mentioned it is thought of as some kind of "matter".

Since matter is energy in a very dense form the meaning might just be that it is energy and because I am a novice I always thought of it as what we call matter in our daily lives. Well similar to it but "hidden".

Do you think that dark-matter could be more like "use of energy"/"time" or something in that direction? Kind of more like a subjective "thing" then a "solid" thing.

Well back to the question at hand.

I might just be more of a beginner then you matt22 so be careful to use my words as a part of your understanding. I just want to share my raw thoughts.

I think that the universe is infinite. It might go through infinite cycles, dont know. I think that our experience of time causes that we can not see that the universe is more a subjective "thing/place" then a place with space and "solid" things occupying it like a room with furniture.
For light that is travelling in space and does not "hit/join with" anything all is at once. There is no time to count so for light there can be no start or end.

My two cents, what ever they are worth.

Amb

narnug

[DragonFly]

My two cents, what ever they are worth.

Well, it is only a penny for one's thoughts and two cents came out of it, so, there is a profit of one cent every time this happens.

Dark Matter:
http://www.sciencechatforum.com/viewtopic.php?f=128&t=22624

[narnug]

My two cents, what ever they are worth.

Well, it is only a penny for one's thoughts and two cents came out of it, so, there is a profit of one cent every time this happens.

Dark Matter:
http://www.sciencechatforum.com/viewtopic.php?f=128&t=22624

Thanks DragtonFly.

The text is very deep in your post. I will have to read it when I have more peace and quiet around me.
Lots of folks here at my end now. Looking forward to "sink" into it.

All my best

narnug