would a black hole eventually get ripped apart?

[space cadet]

I was sitting in the bathtub today watching my skin get pruny and thinking about black holes (this is something I do frequently) when an interesting thought occured to me. We know that the universe is constantly expanding into infinity, right? A black hole, as I understand it, is the exact opposite except on a much smaller scale--it's constantly collapsing into infinity. Suppose that the big crunch theory doesn't work and the universe continues to expand at its current rate. Would it eventually rip all of its black holes into peices? Just curious.

[milli360]

Think of it as competing forces, which operate on different scales.

For instance, the gravitational force of the galaxy is millions of times stronger than the gravitational force of the sun or the moon, but the tidal force (which tends to "rip things apart"!) of the galaxy is miniscule when compared to that of the sun or moon. And the tidal force of any of them, on your bathtub, is miniscule when compared with the effect of just your own body in the water.

[Betenoire]

Actually, black holes would just burn out. Hawking goes into this in A Brief History of Time (which is the only reason I can say what I'm about to):

Virtual particle pairs form constantly, everywhere (probably inside you, but I've never gotten an answer on that one). Usually they just annihilate and the universe has no clue, but under strong gravitational forces (say, next to a black hole) one gets sucked in and the other goes spiraling off.
This means that black holes are actually radiating energy, which means they're losing energy and therefore mass.
Over a very long time span, a black hole's mass will decrease (assuming no matter falls into it) and it will boil away. Of course, we're talking about time spans many times longer than the current age of the universe. So that radiation will be what travels through the heat-death universe.

There's also the possibility that black holes were formed by the Big Bang. Depending on their mass, they will have boiled off already, or they will boil off soon, or right now (If they have the mass of a large mountain, I think). Astronomers are looking for signs of those black holes right now.

[skrap1r0n]

interesting side note, if negative particles are primarily what gets sucked in, does that mean a black hole is a super dense source of Antimatter?

If positive matter gets sucked in, and collides with antimater particled past the event horizon or when it hits the singularity what happens? do they anniahlate each other?

[wedgebert]

Negative particles doesn't mean antimatter.

Anything that happens past the event horizion, will continue to fall towards the singularity, even antimatter/matter annihilation.

As the singularity itself, as far as I've been able to glean from modern understanding, matter as we know doesn't exist. The sinuglarity is strong enough to overcome the Pauli Exclusion Principle, and so two particles CAN occupy the same point in space at the same time. This is how the singularity becomes near infinitely small, particles would be constantly broken up into their building blocks and those blocks broken down further until some natural limit was reached. Then all these tiny particles would end up in a space equal to the size of just one. A true point mass.

Of course, this changes if the black hole spins, but that's another thread.

[eburacum45]

Interesting question;
if the acceleration of the expansion of the universe continues, at some far distant point in time our very atoms will be ripped apart by that expansion;

this is the so-called 'big rip' scenario.

Last I heard it was not expected to happen for a very large number of gigayears, if at all.

However if it did, would it affect black holes? My gut feeling is no;

the expansion of space will not affect a dimensionless point mass, so black holes will just sit there, surrounded by nothing coherent, until they radiate away (by Hawking radiation).

[Kaptain K]

1) Antimatter has positive mass.
2) E=mc^2. Even if matter and antimatter do anihilate each other, the total gravitation of the black hole is unchanged.
3) Hawking said "black holes have no hair", meaning that the only characteristics of a black hole are mass, charge and spin. Whether you add matter, antimatter or even energy (photons) is irrelevant.

[ToSeek]

3) Hawking said "black holes have no hair", meaning that the only characteristics of a black hole are mass, charge and spin. Whether you add matter, antimatter or even energy (photons) is irrelevant.

Black holes also have a temperature, which was baffling for a while until Hawking came up with his radiation concept.

[Disinfo Agent]

if the acceleration of the expansion of the universe continues, at some far distant point in time our very atoms will be ripped apart by that expansion;

this is the so-called 'big rip' scenario.

Which, I believe, is a misconception. The 'expansion of the universe' means that galaxies are getting farther apart, on average. Expansion does not occur on smaller scales, like, say, that of our solar system.

[JohnOwens]

3) Hawking said "black holes have no hair", meaning that the only characteristics of a black hole are mass, charge and spin. Whether you add matter, antimatter or even energy (photons) is irrelevant.

Black holes also have a temperature, which was baffling for a while until Hawking came up with his radiation concept.

I'd take that as meaning "three independent characteristics", the temperature being determined by the mass. Otherwise, you might as well add in radius, circumference, surface area, expected lifetime,...

[Bob]

if the acceleration of the expansion of the universe continues, at some far distant point in time our very atoms will be ripped apart by that expansion;

this is the so-called 'big rip' scenario.

Which, I believe, is a misconception. The 'expansion of the universe' means that galaxies are getting farther apart, on average. Expansion does not occur on smaller scales, like, say, that of our solar system.

It's not a misconception, but it is an unproven theory of a possible end-of-the-universe outcome if the rate of acceleration in the cosmic expansion were to keep increasing.

http://www.space.com/scienceastronom...ip_030306.html

[eburacum45]

if the acceleration of the expansion of the universe continues, at some far distant point in time our very atoms will be ripped apart by that expansion;

this is the so-called 'big rip' scenario.

Which, I believe, is a misconception. The 'expansion of the universe' means that galaxies are getting farther apart, on average. Expansion does not occur on smaller scales, like, say, that of our solar system.

Well, I hope you are right; I personally find the 'Big Rip' a particularly ugly concept.

but in that scenario expansion does extend to the sub-atomic level;
from
http://physics.about.com/b/a/023806.htm

About 60 million years before the end, the Milky Way would be torn apart. About 3 months before the end the solar system would become undone. About 30 minutes before that the Earth would explode. And about 10^-19 seconds before the ultimate moment of doom, atoms would be pulled apart.

[AGN Fuel]

Hawking said "black holes have no hair", meaning that the only characteristics of a black hole are mass, charge and spin. Whether you add matter, antimatter or even energy (photons) is irrelevant.

Just a nitpick. I believe it was John Wheeler of Princeton who coined this phrase.

[space cadet]

Thanks guys for the awesome info

I feel so enlightened! Now can you all explain to me the meaning of life? lol

yeah, yeah... I know. 42.

[Kaptain K]

Hawking said "black holes have no hair", meaning that the only characteristics of a black hole are mass, charge and spin. Whether you add matter, antimatter or even energy (photons) is irrelevant.

Just a nitpick. I believe it was John Wheeler of Princeton who coined this phrase.

I stand corrected! ops:

[Disinfo Agent]

And so do I, even though the article in the link given by Bob does say:

The standard view

Driving the known acceleration of the universe's expansion is a mysterious thing is called dark energy, thought of by scientists as anti-gravity working over large distances.

Conventional wisdom holds that the acceleration will proceed at a constant rate, akin to a car that moves 10 mph faster with each mile traveled. With nothing to cap the acceleration, all galaxies will eventually recede from one another at the speed of light, leaving each galaxy alone in a cold, dark universe within 100 billion years. We would not be able to see any galaxies outside our Milky Way, even with the most powerful telescopes.

From the article linked to by eburacum45:

About 60 million years before the end, the Milky Way would be torn apart. About 3 months before the end the solar system would become undone. About 30 minutes before that the Earth would explode.

Would the Earth and the Sun still be around by then?

[HenrikOlsen]

I feel so enlightened! Now can you all explain to me the meaning of life? lol

yeah, yeah... I know. 42.

Nononono, 42 is the answer to "The ultimate question about life, the universe and everything."

"What is the meaning of life?" is a completely different question. and the answer to that is Breeding.

Sorry for going offtopic.

[Kaptain K]

I feel so enlightened! Now can you all explain to me the meaning of life? lol

yeah, yeah... I know. 42.

Nononono, 42 is the answer to "The ultimate question about life, the universe and everything."

"What is the meaning of life?" is a completely different question. and the answer to that is Breeding.

Sorry for going offtopic.

Inhale...exhale...repeat as necessary! No, wait. That's the secret of breathing. ops: Nevermind!