altering space "black holes"

[XairstrikeXD]

I have a question. if there were to black holes relativley close to each other, would the gravity from the both of them eventually combine the two and rip an even bigger hole in space time. or if they were the *spinning* kind would the spin around each other lik gears.
By spinning kind i mean the kind that spins dragging space with it.

 

[MeteorWayne]

The theory is that since two black holes orbiting each other are radiating gravitational radiation, they will lose enrgy from the orbit and merge into a larger black hole of the combined masses.

Black holes don't really "rip a hole in space time", though. They just sit (or sit and spin) there as a mass with gravity too strong for light to escape.

 

[XairstrikeXD]

would the gravitational pull increase when they merged.

 

[MeteorWayne]

Not really. The two black holes would have the same amount of mass before and after the merger, and would be in such a small orbit, unless you were very close (within a few hundreds of thousands of km) the gravitaional effect would be no different.

Being called (or being) a black hole makes no difference. It's the same amount of mass; it's only different in how much space it takes up. Unless you are REALLLY close, it makes no difference at all.

People seem to think that a black hole is some kind of magical object. It's not. It's just a certain amount of mass in a very small space. For objects many AUs or light years away, it is exactly the same. If you are a light year away, whether the mass is spread across a thousand stars in a few AUs, or concentrated into one object like a black hole, it makes no difference.

 

[R1]

The dark energy Big Rip fate of the universe is said to eventually expand space so much that
not even atoms and particles will survive.


What can expansion like this do to black holes? Neutralize them? Expand them a la Big Bang style?


:shock:

 

[weeman]

would the gravitational pull increase when they merged.

No.

Since the gravitational pull of a black hole is equal to the speed of light, the two combined black holes could not produce a pull that is greater because that would mean their combined gravitational pull would be greater than the speed of light, which according to Einstein is impossible.

The reason light cannot escape a black hole is due to the fact that a black hole's escape velocity matches the speed of light. In other words, once a beam of light crosses beyond the boundry known as the event horizon, it faces an escape velocity that is as fast as itself, therefore making it unable to travel back outside of the event horizon.

 

[weeman]

The dark energy Big Rip fate of the universe is said to eventually expand space so much that
not even atoms and particles will survive.


What can expansion like this do to black holes? Neutralize them? Expand them a la Big Bang style?


:shock:

Hmmm. I'd say a la big bang style. Here's my best answer:

If expansion becomes so powerful, that it eventually pulls apart all matter and energy, then this must mean that not even black holes would survive. As we see in modern cosmology, there's evidence that suggests that at the brief moment of inflation, shortly after the initial big bang, space expanded at a velocity that was much faster than light. So, could we then say that it's possible that expansion would once again reach this point in the distant future? Would this then mean that if black holes are faced with superluminal expansion on a molecular level that they too would be overpowered?

 

[Saiph]

Since the gravitational pull of a black hole is equal to the speed of light, the two combined black holes could not produce a pull that is greater because that would mean their combined gravitational pull would be greater than the speed of light, which according to Einstein is impossible.

You're confusing the balance between escape velocity and light speed for the strength of gravity. The event horizon is just as you defined it. However the strength of gravity of the BH determines the diameter of the event horizon. So BH can have more, or less gravity. The result is a larger (or smaller) event horizon.

Two merged BH's would have a stronger gravitational attraction to objects outside the Event Horizon, and a larger diameter event horizon.

 

[XairstrikeXD]

event horizon being the point were you cant escape? please explain because i think im wrong

 

[MeteorWayne]

No you are right, Once you are closer than the event horizon, then there is no escape for anything...matter, light, or any other radiation. the only exception might be Hawking radiation which is a very small probabilty circumstance where quantum particles pop into existance on either side of the horizon. Very rare, if it exists at all.

 

[XairstrikeXD]

Ok thanks

 

[R1]

You know what though? If a naked black hole is floating around surrounded by large voids of dark energy,
shouldn't we be seeing black holes ripped apart by the dark energy?

Perhaps not. Black holes and quantum particles may be the hardest things that dark energy can rip apart ?