Quote:
Originally Posted by xelasnave
I put the proposition recently that a black hole in my view could not influence a galaxy given its relative size to the galaxy.
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Not all galaxies have central black holes. In fact, two galaxies (albiet small and irregular satellite galaxies) that you would have observed countless times don't have central black holes - the small and the large magellanic clouds.
Also, for galaxies that do have central black holes - they do influence the galaxy. They are observed by looking at the rotation of the stars around the galaxy core - put simply, the stars rotate faster due to the gravitational influence of the black hole. By this simple definition, black holes influence galaxies.
Quote:
Originally Posted by xelasnave
Why are black holes no larger than 100 million solar masses.. It seems they have run out of food!
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Perhaps they are just too young? Ask this question again in 150 billion years and they might be bigger
although I suspect that some scientist somewhere will be able to come up with a theory that suggests in the first 100 thousand years of the universe age some sort of thing happened whereby the density of the universe was decreasing at a specific rate due to the universes expansion which put an upper limit on these things (just as we could also put an upper limit on galaxy size - we don't see galaxies with 4 trillion stars for example)