# Binary Blackholes

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In a late night conversation with a friend of mine, he brought up that some science show said that in some galaxy there are two black holes moving towads each other and asked me what I thought would happen if they collided. Well, somehow the conversation changed into being what would happen if two black holes passed each other perfectly and caught in each others event horizon perfectly so they spun around each other. Would they be stable enough to hold like that, and what would happen?

Secondly, assuming they would be stable, I brought up the idea, what if a perfect sphere was placed at the perfect center of the two perfectly spinning blackholes, what would happen to the perfect sphere? Let's say the sphere was made out of water. Together using our limited knowledge of sciences, we assumed the force of the gravitational pull from the blackholes would cause the object to stay in the center and not move due to the fact it should have an equal amount of forcecomging from each side at any given time. And the movement of the black holes probably spinning at speed greater than light would ause the sphere to spin, accelerating until it reaches the speed of the blackholes. And the centerifical force from the sphere of water would cause it to grow and become slightly disk shape, while the force of the event horizons would cause it still to remain stable. But when it hit the speed of light, assuming the black holes are spinging around each other at speed greater than the speed of light, what would happen to the water? We thought it might turn into some kind of pure energy. Is there a theory to what would happen? And can you guys here at sciforums tear down our theorys? I know you guys can. But has any of this been thought of before?

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I'm no astronomer, but I believe the forces of the black holes would rip the water sphere into two halves that was then gobbled up by the two black holes. If you did have some sort of material in the shape of a sphere that could withstand being torn apart and the black holes that where spinning around it then I believe that the black holes would have to be traveling faster than the speed of light in order to get the sphere to travel the speed of light. Also, I think that two rotating, powerful forces on opposite sides of a immobile sphere would cause it to assume a disk shape. I have no idea what would happen if the sphere reached the speed of light. Sounds like an innovative thought, but still bet someone else has thought about it.

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If it was in one of the Lagrange point of the black holes than the sphere will be ok. Or at least it shouldn't move.

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Well, besides the point that it is very likely that the speed of light cannot be attained by conventional means such as acceleration of bodies with mass.

The gravitational acceleration upon the two spinning black holes would cause the event horizons to deform first and foremost, causing the ever popular singularity 'hole' to form within the black hole.

The speeds of the black holes can not reach the speed of light even if ignoring the speed of light limit because gravity is based off the speed of light aswell, the closer the black holes angular velocity to a fraction of c, the longer/less gravitational force reaches the opposing black hole, causing the black holes to fling apart to their respective sides of the universe long before reaching a fraction of c.

If the settings for two black holes to form into a nice circular tango between one another, it will drag the fabric of space with them, erm, called 'frame dragging' i believe, and the higher the mass of either black hole the larger the rotational drag imparted upon the other black hole, causing the hole simplicity of 2 body orbit to get thrown in the bin.

If a black hole is going faster/at than the speed of light ( in relation to the opposing hole i suppose), then its inertial mass is infinite, this is bad, not only does this screw the fabric of space like a chainsaw, but the gravitational field of the black hole will be severely warped if gravity goes at the speed of light, though gravity is considered a property of spacetime, gravity has a speed, instantaneous it is not. If gravitrons is the preferred messenger particle of gravity, and its speed is off light, it will have a 'tough' time transferring gravity between a 100% c velocity object vs a not 100% c velocity object, i'm screwing my own mind up trying to figure out what i'm trying to say.

Okay, now supposing the 2 black holes are going at a relatively high fraction of c, then the initial sphere inside will have different forces acting upon it, only at perfect origin will it have zero gravitational pull in a sense (accepting a perfect orbit and positioning of the black hole pair), the rest of the sphere will immediately be strung along at the whim of the fluctuating field values, and even a neutron star (densities of a few tons in a teaspoon, tension strength high...) would lose the battle, the strongest tensile known to man is carbon nanotube (right?), not a chance. it will be pulled apart within picoseconds (depending on the distance from the black holes), rotation be damned.

And ignoring all of this, the faster (relatively) any material goes, the larger its inertial mass, with c speed having infinite mass, hence any estoric material that can survive such huge gravitational forces will have astounding tension energy and angular velocity, energy would go up exponentially as the blackholes continue feeding it (losing orbital velocity in the process), any material based of physics would come apart, supposing some estoric relic from the big bang like a 0d brane, it would probably have enough energy to cause physics to break down, All guesswork now .

But it would make for a hell of a movie.

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But it would make for a hell of a movie.

Hi Skoteinos, unfortunately i dont have the link for this but several years ago i came across a technical article where

they did a computer simulation of a collision of two black holes

and they published some individual "frames from the movie"

to show what it looked like.

What I remember seeing frames of is a merger where a considerable amount of the energy is carried away by ripples in spacetime (gravitational waves) caused by the collision.

The collision and merger of black holes must occur from time to time and perhaps the new gravity-wave-detector will "see" events like that.

I know that galaxies do merge (we see them in the act of doing so) and the result is larger galaxies that can contain several black holes (at least one case of this has been observed). So there are situations of several black holes orbiting each other that astronomers know about---or at least one such. I'd say it's a safe bet that BH mergers do happen and eventually will be observed.

I agree with your general message about a lot of energy being involved in the process and also that nobody during merger is going to surpass the speed of light or do anything wicked like that. The people who do computer simulations of stuff like that---their field is called "Numerical General Relativity" and the arxiv search engine should be able to come up with some graphic output like what i saw.

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In a late night conversation with a friend of mine' date=' he brought up that some science show said that in some galaxy there are two black holes moving towads each other and asked me what I thought would happen if they collided. Well, somehow the conversation changed into being what would happen if two black holes passed each other perfectly and caught in each others event horizon perfectly so they spun around each other. Would they be stable enough to hold like that, and what would happen?

Secondly, assuming they would be stable, I brought up the idea, what if a perfect sphere was placed at the perfect center of the two perfectly spinning blackholes, what would happen to the perfect sphere? Let's say the sphere was made out of water. Together using our limited knowledge of sciences, we assumed the force of the gravitational pull from the blackholes would cause the object to stay in the center and not move due to the fact it should have an equal amount of forcecomging from each side at any given time. And the movement of the black holes probably spinning at speed greater than light would ause the sphere to spin, accelerating until it reaches the speed of the blackholes. And the centerifical force from the sphere of water would cause it to grow and become slightly disk shape, while the force of the event horizons would cause it still to remain stable. But when it hit the speed of light, assuming the black holes are spinging around each other at speed greater than the speed of light, what would happen to the water? We thought it might turn into some kind of pure energy. Is there a theory to what would happen? And can you guys here at sciforums tear down our theorys? I know you guys can. But has any of this been thought of before?[/quote']

the ball of water (depending on the black holes in the center) would most likely be spegetified and sucked into the black hole with the strongest gravity.

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Thanks Martin, That sounds pretty interesting, i'll probably surf the web about that stuff once its not 4:21 AM right now , and noz92, you summed it up in a sentence , good man.

I've made a few amateur computer simulations of galaxy collisions, problem is that invoking rotation upon the stars is somewhat more difficult than i thought, too far and the stars fling apart, too close and the stars fling apart, just right and the stars fling apart, its problamatic.

They haven't 'confirmed' black holes as of yet, there's huge amounts of possibilities, and most people agree black holes exist, we're just looking for em now, galactic centers, binary systems etc. A black hole simulation would be really interesting. And once the newer and more powerful particle accelerators come online, and if we find out there are more than 3 spatial dimensions, then perhaps we will be able to build miniature black holes right here on earth, expelling all doubt.

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ummm, okay. As much I really wish I didn't read everything, were are the facts that back up either rbp6's response or Skoteinos reply? Has tests been taken? Can tests be taken? Or can I learn enough and state my original assumptions are fact?

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Black holes exists, its what happens inside them that is in contention.

As for learning enough to make statements like that 'facts' is with rigourous mathematical proof. While theorising about black holes is interesting to say the least, a firm understanding of the in's and out's of general relativiy are advised.

As for spagettification, it depends on the overall size, tiny black holes produce huge tidal forces that would stretch you out, but larger black holes have a smoother gravity 'gradient'.

What are peoples opinions on ring 'singulaities', at the centre possibly of Kerr(rotating) black holes? Is it possible that the centre of such a singularity, would tear a hole in space time? In some bizarre way provide the power outlet to quasars in the most distant part of the universe? Merely conjecture obviously but a possibilty no less??

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Igor Novikov studies the subject of black hole collisions using supercomputers for some time now. Not sure if this is the work Martin referred to. Have a look at CTCs, Time Machines and Black Hole Collisions.

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The Lagrange point between two gravitational bodied is just that - a 'point'. Only at exactly that point will an object feel no force, and as one moves away from the point, the gravitational force will get stronger. So an extended body can only be stationary if its centre of mass is right on the Lagrange point and the forces holding the body together are stronger than the gravitational forces at its extremities.

Water isn't very strongly held together, so even the rather weak gravitational forces at the edge of the ball of water will be enough to suck some of it away. This will disturb the centre of mass and destroy the stability of the water, letting it be sucked into the black holes.

A ball of iron would be more interesting.... (Sounds like an Alastair Reynolds book...)

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Glad I didn't reply to that water thing, severian put it very well. An H2O molecule or small collection of molecules might survive at the centre between the two blackholes, that is until almost anything whatsover gets near it so as to move it. Nevermind how the water got there in the first place...

I guess God and Zeus just made a wager.

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water was just an example...it was the first spherical thing in space my friend could tihnk of. So only the larange point would stay as it was? All else woud be speghettified? That would be awesome to see.

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