yes, I think Einstein must have realised that some kind of theory would have to account for what would happen under the high density situations in dying stars, just that he didn't know what.

Frogmarch, you're starting to present ATM views in Q&A.
Careful!

Grant Hutchison

yes, I know.....

but I always try to qualify, that its my idea, or opinion.

Please don't send me to the pit of doom, I mean ATM!!!

They would merge. An interesting fact is that the radius of a black hole is directly proportional to the mass. So the radius of a black hole with mass 2M is exactly the same as the diameter of a black hole with mass M. What that means in this case is that if you have two matching black holes with their event horizons touching, they already fulfill the conditions for a black hole with the center at the point that they touch, and an event horizon that extends around them both. So you get something that looks something like figure 4 on this page. We can work out what happens after that theoretically, but we'd never actually be able to check. By the time the event horizons touch, the whole system just ends up being a larger black hole, and we no longer have access to any information about what's going on inside.

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Conserve energy. Commute with the Hamiltonian.

Putting aside the spiral gravitation waves and gravitational radiation (Have either been detected?) mentioned by Astronomer and grant huchison: It seems to me that: near misses will occur much more frequently than over lapping event horizons.The accretion disks will collide at perhaps 0.99c, especially, if the relative speed of the singularities, at closest approach is 1/2c or more. This should produce at least a weak gamma burst lasting about one second, if both black holes have an event horizon diameter of 186,000 miles or a bit less.
If the event horizons overlap slightly, up to perhaps 30 percent overlap, the singularities will accellerate toward each other at perhaps several g, but the movement will be close to negligible, if the encounter time is only one or two seconds.
Assuming the accretion disk continues inside the event horizon somewhat as it is just outside the event horizon 0.99c, perhaps 1% of the mass of each black hole will merge, resulting in a third black hole of smaller mass while the 99% of each of the original black holes, do a sling shot maneuver around each other and continue away from each other. This seems reasonable as 99% of the mass did not overlap even briefly. Now it may be that the three black holes will have more close encounters at million to billion year intervals, and eventually merge = they did not escape. I suspect the math does not rule out temporary escape from the event horizon, but suggests that the orbits will eventually cause merger.
The singularity of each black hole is tiny, so mass spiraling in typically misses the singularity, and perhaps the pile up of ions etc trying to enter the one square millimeter of the singularity surface area. If it misses, a sling shot maneuver = gravity assist maneuver occurs, which caries the expanding ionized mass perhaps 90,000 miles toward the event horizon (on the inside) before repeating the spiral toward the singularity. The bottom line is the event horizon may have as much as 50% of the total mass more than a mile from the singularity, even if accretion is less than 1% per million years. Neil

if you're interested in this, perhaps you should read the papers I linked to earlier in this thread, and review Grey's post just above your own.
Because nothing you've written above bears any resemblance to black hole mergers as simulated using the equations of general relativity.

Grant Hutchison

i love these sorts of questions, the ones you'll never knowthe answer to and can't get your mind around, but you keep thinking about how it could be plausible.

i think they have to pass the event horizon. Now the reason you may think that they would be forever free falling i cannot understand. but atthe center of a black hole there is a single point of singularity where gravity is infinite and has no volume, the length, height or depth. It was thought at one point that this is the point where you could be............. not jetisoned, but fall into another part ofthe universe. as in it could be the worm hole that string theory is based off of i mean.

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SAO <3's S.C.W.

apart from my idea that all the matter that is associated with the black hole, is compressed outside the event horizon....blah..blah..blah, I have always found it difficult to accept that two singularities could combine.

how can two infinities approach each other and then combine?

what happens in between the two singularities?

infinity+infinity=infinity

sure, but the combination of the two black holes masses, is finite.

It doesn't jell with me...although I'm not sure how to explain why.

maybe it is the sets of infinity idea; that one type of infinity can be bigger than another, like the set of numbers that are divisible by 2, is bigger than the set of numbers divisible by 3, but they are both infinite sets.

if two singularities approached each other, I think, or feel that you are going from one set to the next higher set, but I'm guessing that the jump from one set to the next is not continuous.

I don't know perhaps I'm a talkin' cobblers again.

So finite mass + finite mass = finite mass.
When objects combine, you don't add their densities, you average them, weighted for any inequality in volume.

Grant Hutchison

In the link from Grants post there is a shape of warped space(time) as the two singularities merge, like two trouser legs in nearing proximity with a disappearring crotch, I think this geometry explains how the singularities move towards each other so fast, in the way described by Grey, maybe something along the lines of the speed of the intersection point of scissors closing at relativistic speed. Meanwhile, the event horizons would become distorted and for some time after the singularities merge would retain a complex toroidal shape, it's not just two simple spherical regions overlapping and combining.

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plenty of woo, at the hotel hoagaland...

There's a lovely technical term for what happens as the initial dumbell-shape of the combined event horizon spins furiously, radiating gravitational waves until the two singularities merge and the whole thing can settle into an equilibrium state. It's called ring-down.

Grant Hutchison

Gravity? it'sthe strongest force in the universe, and it is wat controls the boundries and rules of physics, so i kind of think it's like the boss of the universe, and he can do w/e he wants.

Well, i don't think wat may make it simpler is don't think of the singularitys as if they have volume, because they don't they dont have dimensions, it's just a point of infinite gravity, so there can't be anything between them.

Now, why is it hard to believe two never ending masses can't just meld to make one? It's like a flame, you can add the flame to another flame (now i don't mean wood to wood, or scrap to srcrap, or tinder to tinder) i mean just the flame, you can add them together but they don't get bigger or smaller.

yea but those divisible number aren't infinite so i kinda don't think it's relevant. And infinite masses or bodies or w/e you will call it have no value or size so there's no way to compare sizes. infinite means they are always expanding, always getting bigger, a fixed size would make it finite.

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SAO <3's S.C.W.