Thread: Black hole collapse?

Let's ignore the white hole theory for a second. As more mater enters the black hole, it is compressed. Eventually, there must be a point where the magnetic forces between the nuclei becomes so powerful that it.....

what?

If a black hole is filled to the brim so to speak, what happens? does it explode? Convert all the mass into energy? If so, where does the energy go?

black holes evaporate: A two particles are created at the edge of the event horizon, one falls back into the BH but the other has enough energy to escape the gravitational pull, this is known as hawking radiation.

Originally Posted by Raggedjoe

As more mater enters the black hole, it is compressed.

This statement is incorrect. As more matter enters a black hole, it gets bigger.

Originally Posted by mathman

Originally Posted by Raggedjoe

As more mater enters the black hole, it is compressed.

This statement is incorrect. As more matter enters a black hole, it gets bigger.

I am referring to the matter that is entering the black hole, not the black hole itself.

Originally Posted by Nevyn

black holes evaporate: A two particles are created at the edge of the event horizon, one falls back into the BH but the other has enough energy to escape the gravitational pull, this is known as hawking radiation.

But what happens to all the mater inside the black hole?

it is ripped to shreds, presumambly down to things below even the subatomic particles (maybe into energy) anyway the point is no one really knows what happens at the singularity.

That's exactly the point. In a black hole, the gravity is so strong that nothing known to us can prevent the matter from collapsing to a single point. Matter is not as solid as many believe. It is mostly composed of empty space. However, it is well possible that once we unify General Relativity with Quantum Mechanics, the answer is a different one.

Originally Posted by Dishmaster

That's exactly the point. In a black hole, the gravity is so strong that nothing known to us can prevent the matter from collapsing to a single point.

In that case, wouldn't the black hole itself be the size of a point?

If I have a ball of Play Dough and I compress it more and more, then the volume of the ball shrinks. If a black hole collapses matter unto a point, then the black hole is also a point.

Also, does this mean black holes have infinite density?

M/V approaches infinity for V sufficiently small? (odd union of series math and physics but it gets the point across)

Originally Posted by Raggedjoe

Originally Posted by Dishmaster

That's exactly the point. In a black hole, the gravity is so strong that nothing known to us can prevent the matter from collapsing to a single point.

In that case, wouldn't the black hole itself be the size of a point?

If I have a ball of Play Dough and I compress it more and more, then the volume of the ball shrinks. If a black hole collapses matter unto a point, then the black hole is also a point.

Also, does this mean black holes have infinite density?

M/V approaches infinity for V sufficiently small? (odd union of series math and physics but it gets the point across)

The radius of a black hole is commonly defined as the radius of its event horizon. (the point where the escape velocity equals c.) Since no information can leave the black hole through the event horizon, we can not "see" what's actually goes on in there. Whether or not a pont of infinite density(a singularity) occurs at the center is still a point of debate.

Kerr ring singularity:
http://www.daviddarling.info/encyclo...lack_hole.html

A star spins and when it collapses into a black hole it continues to spin because a property known as angular momentum can not be destroyed or lost. So the poles collapse downward into the denser part of the sphere and then this disk spins into a ring of matter for the same reason. The ring continues to contract into an absolutely flat ring with the diameter of the Planck scale known as a singularity. With a height component of zero, the volume (length x width x height) is then also zero. Since mass divided by volume is density, the density of the singularity approaches infinity.

Originally Posted by Arch2008

Kerr ring singularity:
http://www.daviddarling.info/encyclo...lack_hole.html

A star spins and when it collapses into a black hole it continues to spin because a property known as angular momentum can not be destroyed or lost. So the poles collapse downward into the denser part of the sphere and then this disk spins into a ring of matter for the same reason. The ring continues to contract into an absolutely flat ring with the diameter of the Planck scale known as a singularity. With a height component of zero, the volume (length x width x height) is then also zero. Since mass divided by volume is density, the density of the singularity approaches infinity.

umm.....1 problem u said mass divided by volume. is the volume is 0 then this problem cannot be solved, because you cannot divide by 0

Originally Posted by Brokenazs

Originally Posted by Arch2008

Kerr ring singularity:
http://www.daviddarling.info/encyclo...lack_hole.html

A star spins and when it collapses into a black hole it continues to spin because a property known as angular momentum can not be destroyed or lost. So the poles collapse downward into the denser part of the sphere and then this disk spins into a ring of matter for the same reason. The ring continues to contract into an absolutely flat ring with the diameter of the Planck scale known as a singularity. With a height component of zero, the volume (length x width x height) is then also zero. Since mass divided by volume is density, the density of the singularity approaches infinity.

umm.....1 problem u said mass divided by volume. is the volume is 0 then this problem cannot be solved, because you cannot divide by 0

when you divide by 0 you get infinity

Erm if I remeber correctly the answer is it forms a quasar, Not sure how so much energy can escape a Black hole but there ya go

Originally Posted by Booms

Erm if I remeber correctly the answer is it forms a quasar, Not sure how so much energy can escape a Black hole but there ya go

A quasar is a super massive black hole in the process of growing. As matter falls in toward the black hole it forms an accretion disk. This matter is has extremely high velocities, and when it collides with itself it gives high level radiation. Once the Black hole has swept the local area free of matter, the Quasar settles down to just a being a black hole.

In other words, quasars are the birth pangs of the super massive black holes that reside at the center of galaxies.

Originally Posted by Janus

Originally Posted by Booms

Erm if I remeber correctly the answer is it forms a quasar, Not sure how so much energy can escape a Black hole but there ya go

A quasar is a super massive black hole in the process of growing. As matter falls in toward the black hole it forms an accretion disk. This matter is has extremely high velocities, and when it collides with itself it gives high level radiation. Once the Black hole has swept the local area free of matter, the Quasar settles down to just a being a black hole.

In other words, quasars are the birth pangs of the super massive black holes that reside at the center of galaxies.

Quasars are only found at the edge of visible space, no? So aren't any new galaxies forming closer to home, both in time and space?

Originally Posted by KALSTER

Quasars are only found at the edge of visible space, no? So aren't any new galaxies forming closer to home, both in time and space?

The galaxies formed during a time when the Universe was a lot denser and more chaotic, about 300 million years after the BB. So no, there are not any new galaxies forming now nor in the near past.

ok, I didn't know that the black holes matter supposedly spins, but what about new matter? The Matter is clearly behind the event horizon, but when new matter adds to the black hole this matter will not penetrate the event horizon, logically creating a sphere of matter around the core matter of the sun, extending the event horizon radius, or am I mistaken? Therefor you would have a spinning core and spheres of matter around this core.
There are still many unanswered questions left (to me), where is the event horizon exactly? Does it start when the matter of a black hole ends, meaning there is no space between new entering matter and the core matter. Or does the event horizon located exactly on the outer rim of the black hole, leaving no space between core and new matter.
The nearer you are to the eventhorizon, the slower the matter close to it will move though time, so is the event horizon A: the point exactly before motionlessnes in time or B: the actual absence of motion in time?

Originally Posted by Arch2008

Kerr ring singularity:
http://www.daviddarling.info/encyclo...lack_hole.html

A star spins and when it collapses into a black hole it continues to spin because a property known as angular momentum can not be destroyed or lost. So the poles collapse downward into the denser part of the sphere and then this disk spins into a ring of matter for the same reason. The ring continues to contract into an absolutely flat ring with the diameter of the Planck scale known as a singularity. With a height component of zero, the volume (length x width x height) is then also zero. Since mass divided by volume is density, the density of the singularity approaches infinity.

Note he says "approaches" infinity. The volume probably only approaches zero, rather than reaching it.

Originally Posted by Dishmaster

That's exactly the point. In a black hole, the gravity is so strong that nothing known to us can prevent the matter from collapsing to a single point. Matter is not as solid as many believe. It is mostly composed of empty space. However, it is well possible that once we unify General Relativity with Quantum Mechanics, the answer is a different one.

The only counter force I can think of is simple conservation of momentum. Since friction is the only force likely to create a net diminishing in the momentums of the separate particles, and does so by creating heat (which is itself just another form of motion), it stands to reason that the particles in the system have to still be moving at their original speeds, or have transferred those speeds to each other.

Early this year, an 18,000,000,000 solar mass black hole was found. We don't know if there is an upper limit to them.

Hawking radiation? Doh!

Originally Posted by Nevyn

when you divide by 0 you get infinity

Wrong! This is something I tell my students often! Division by zero is not defined! tan 90° is not defined. What is infinity? E.g., the infinity of natural numbers. How many? Answer given by Cantor: Aleph null.

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they had. But now they have them in black and also in white.

Originally Posted by Cyberia

Early this year, an 18,000,000,000 solar mass black hole was found. We don't know if there is an upper limit to them.

There is an upper limit. Something like 3 million solar masses, I recall. Large BH's have powerful jets that clean out the neighborhood, preventing further growth.