Black Holes

[ph_low]

I've just been doing some reading on Black Holes, and i found that theoretically there is an infinite mass at the singularity inside a black hole. Surely something with an infinite mass would require an infinite energy, but i've always thought that in the universe there was only a finite amount of energy, so why is this possible?
Sounds like a stupid question maybe, but i'm only in my first year of college :biggrin:

[haveblue]

The black hole doesn't have infinite mass, just the mass it has is "infinitely" dense..

[marcus]

The black hole doesn't have infinite mass, just the mass it has is "infinitely" dense..

I agree with haveblue
people observe black holes (or what they are pretty sure are black holes) and see stuff orbiting very fast and close in, around them
and they measure the masses
and it turns out to be anything from a few times the mass of the sun,
to millions of solar masses, and even more

I think the hole that's been observed at the center of our galaxy is measured to be around 3 million solar masses

anyway the masses of holes are not infinite.

Now as to the density at the center-----that would be infinite if there was some finite mass packed into a ZERO VOLUME

but the latest theoretical investigations of the centers of black holes suggest that it is NOT a zero volume

by quantizing the theory of gravity (improving General Rel by quantizing it) various researchers are discovering that there is NOT a singularity at the center

instead there is a region of very high, but not actually infinite, density.

Something to notice is that we only know things theoretically about centers of black holes. The center is surrounded by an event horizon (almost like a shell) from which does not allow us to look in.

Three quantum gravity authors who have written papers recently to show that there is no singularity (no spot of zero volume and infinte density) inside are Leonardo Modesto, Viqar Husain, Oliver Winkler.
You can find their papers at arxiv.org by searching using the author name.

However the best and latest information about what is at center of black hole (instead of singularity) is a 10 September 2004 talk given at PennState by Abhay Ashtekar. The audio and slides are downloadable. Let me know if you are curious and want a link. Abhay is world class and this is very new stuff.

[nobunaga84]

I agree with haveblue
people observe black holes (or what they are pretty sure are black holes) and see stuff orbiting very fast and close in, around them
and they measure the masses
and it turns out to be anything from a few times the mass of the sun,
to millions of solar masses, and even more

I think the hole that's been observed at the center of our galaxy is measured to be around 3 million solar masses

anyway the masses of holes are not infinite.

Now as to the density at the center-----that would be infinite if there was some finite mass packed into a ZERO VOLUME

but the latest theoretical investigations of the centers of black holes suggest that it is NOT a zero volume

by quantizing the theory of gravity (improving General Rel by quantizing it) various researchers are discovering that there is NOT a singularity at the center

instead there is a region of very high, but not actually infinite, density.

Something to notice is that we only know things theoretically about centers of black holes. The center is surrounded by an event horizon (almost like a shell) from which does not allow us to look in.

Three quantum gravity authors who have written papers recently to show that there is no singularity (no spot of zero volume and infinte density) inside are Leonardo Modesto, Viqar Husain, Oliver Winkler.
You can find their papers at arxiv.org by searching using the author name.

However the best and latest information about what is at center of black hole (instead of singularity) is a 10 September 2004 talk given at PennState by Abhay Ashtekar. The audio and slides are downloadable. Let me know if you are curious and want a link. Abhay is world class and this is very new stuff.



Plz let me have it.