What Happens to Matter in a Black Hole?

[GRAViL59]

Strangely enough I have just post a question with a similar though in mind. Mass is a very important quality to have in our universe, the larger your mass the less chance you have of being annihilated.

My thinking being that as a black hole’s mass increases its gravity will increase this in turn attracting even more material towards it… a massive black hole could easily absorb stars and smaller black holes and just keep growing? It makes sense to me that at the centre of such massive object matter would be shredded and stripped back to its most basic constituents and perhaps even “squeezed” into another dimension (I don’t like the word dimension but I can’t think of an alternative).

 

[DaveC426913]

Strangely enough I have just post a question with a similar though in mind. Mass is a very important quality to have in our universe, the larger your mass the less chance you have of being annihilated.

My thinking being that as a black hole’s mass increases its gravity will increase this in turn attracting even more material towards it…

A diffuse, gaseous cloud of mass m has precisely the same gravitational effect on its surroundings as a black hole of mass m. i.e. the mass that existed before it became a black hole had just as much pull on the stars gas and dust around it as it will once it collapses into a black hole.

 

[GRAViL59]

I have always seen massive objects (stars, black holes..) as cosmic vacuum cleaners... I assumed that the more massive an object is the more material will "gravitate" towards it...

I'm not sure if black holes are constantly getting larger or if they are getting smaller due to the effects of Hawking Radiation??

 

[DaveC426913]

I assumed that the more massive an object is the more material will "gravitate" towards it...

It is a good assumption. But it is not endemic to black holes. Any object (such as a diffuse cloud) will attract material directly proportional to its mass.

Gravitationally, BHs are nothing special. If the sun were magically replaced with a BH of the same mass as the sun, the solar system would happily continue to pirouette about it as if nothing had happened.

The key difference with a BH is that, whereas the closest you could get the sun is its surface (400,000 miles from its center), the closest you could get the BH is only a few miles - this means that, below 400,000 miles and above a few miles, gravity can be vastly, vastly increased - millions of g's.

But even Mercury, zipping around a few millions of miles overhead would be blissfully ignorant of it.

In a nutshell, the gravity well from the Sun and the gravity well from the BH both have the same slope - it's just that, with the BH, you can go much farther down the well.

I'm not sure if black holes are constantly getting larger or if they are getting smaller due to the effects of Hawking Radiation??

It depends on if anything gets close enough to be eaten. BHs with lots around them can "gorge" themselves. BHs with little around them can "starve".

 

[GRAViL59]

Thanks for the reply... I'll apply a bit more thought to all this stuff.

I think you should look at my other post... because you are a Smartypants! We should have a beer together.

Thanks again for your reply

 

[DaveC426913]

I think you should look at my other post...

Other post? You mean the gravity is a weak force post?