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What would happen if two black holes collided?
I figure that since black holes have enough gravitational force to hold light in, that they must have enough force to accelerate an object falling into one past the speed of light. (The normal adding of mass with speed as per the theory of relativity would only accelerate it, as added mass would mean more gravitational attraction, right?) So, if you dropped a small object into a black hole, it would hit the center at (or even above) the speed of light.
Now what if, by some enormous unlikelihood, two black holes were on a collision course with each other...
The closer they got to each other the more they would be accelerated towards each other, and even if my theory is wrong, their combined speed at the time of impact could be above the speed of light. Now, when two objects collide, if they shatter, some pieces of the object(s) that shatter can be propelled much faster than the combined speed of impact.
So, I theorize that if two black holes collided, it could produce relatively small objects shooting out faster than the speed of light. These objects would still be stretched by the black holes' gravity as it sped away, and would become long and thin. I would also theorize that it would be composed of sub-atomic particles (or even raw strings (as of super-string theory)) because of the black holes' crushing gravity.
An object traveling faster than light, very thin; thin enough to slip right through normal atomic structures...
Now, what does this object sound like? A cosmic string. So, could cosmic strings be caused by collisions of black holes?
Now what if, by some enormous unlikelihood, two black holes were on a collision course with each other...
The closer they got to each other the more they would be accelerated towards each other, and even if my theory is wrong, their combined speed at the time of impact could be above the speed of light. Now, when two objects collide, if they shatter, some pieces of the object(s) that shatter can be propelled much faster than the combined speed of impact.
So, I theorize that if two black holes collided, it could produce relatively small objects shooting out faster than the speed of light. These objects would still be stretched by the black holes' gravity as it sped away, and would become long and thin. I would also theorize that it would be composed of sub-atomic particles (or even raw strings (as of super-string theory)) because of the black holes' crushing gravity.
An object traveling faster than light, very thin; thin enough to slip right through normal atomic structures...
Now, what does this object sound like? A cosmic string. So, could cosmic strings be caused by collisions of black holes?
Seems a bit odd to conduct a survey on this. What difference will peoples votes make to the answer ?
The answer is that they will circle and eventually combine into 1 BH with the solar mass of the two.
Want to see a movie of it ?
Here you go (well, a simulation, not a movie, but it's very nice).
http://www.youtube.com/watch?v=xVgPplOgB1g
Here's some physics on the issue
Url
http://192.58.150.33/pnu/2000/split/517-2.html
Hang on...addendum. I missed your central point because I skimmed it too quickly.
OK the point being c and it's tenability in such a system ?
Last edited by Bikerman on Wed Nov 01, 2006 1:17 am; edited 2 times in total
The answer is that they will circle and eventually combine into 1 BH with the solar mass of the two.
Want to see a movie of it ?
Here you go (well, a simulation, not a movie, but it's very nice).
http://www.youtube.com/watch?v=xVgPplOgB1g
Here's some physics on the issue
Url
http://192.58.150.33/pnu/2000/split/517-2.html
Hang on...addendum. I missed your central point because I skimmed it too quickly.
OK the point being c and it's tenability in such a system ?
Last edited by Bikerman on Wed Nov 01, 2006 1:17 am; edited 2 times in total
Ok...so it sounds like a quite well thought through theory...and there are definitely some clever bits to it however, my problem with it, at the moment, is that any object with a mass can never reach the speed of light.
Here's an attempt at an explanation:
To get an object to accelerate, a force must be applied to it. The formula for calculating this force is (in its more complex form):
- meaning the change in (mass * velocity) over a set amount of time.
This looks fine initially - there is no reason why a bigger and bigger force shouldn't be applied as the black holes get closer to each other, which would mean the black holes could reach the speed of light.
There is a problem however. In terms of the theory of relativity, mass is defined as:
where m is the mass of the object, m0 is the mass of the object at v=0, v is the velocity and c is the speed of light.
Now lets try and make v = c
Now an unlimited mass is not only a incomprehensible concept, it also messes up the top formula:
...so the Force required to take an object to or beyond the speed of light is infinite. A black hole has a LOT of gravitational pull, and does assert an enormous force on objects, but the speed of light will never be reached
EDIT: dammit, bikerman beat me to it
I put the calculations in quote tags to make them easier to destinguish and read - and because they are taken in half from my physics book. (i study physics at college
Here's an attempt at an explanation:
To get an object to accelerate, a force must be applied to it. The formula for calculating this force is (in its more complex form):
| Quote: |
| F = d(m*v)/dt |
- meaning the change in (mass * velocity) over a set amount of time.
This looks fine initially - there is no reason why a bigger and bigger force shouldn't be applied as the black holes get closer to each other, which would mean the black holes could reach the speed of light.
There is a problem however. In terms of the theory of relativity, mass is defined as:
| Quote: |
| m = m0 / sqrt(1 - v^2/c^2) |
where m is the mass of the object, m0 is the mass of the object at v=0, v is the velocity and c is the speed of light.
Now lets try and make v = c
| Quote: |
| m = m0 / sqrt(1 - c^2/c^2)
<=> m = m0 / sqrt(1 - 1) <=> m = m0 / 0 <=> m = ∞ (infinity!) |
Now an unlimited mass is not only a incomprehensible concept, it also messes up the top formula:
| Quote: |
| F = d(∞*v)/dt
<=> F = ∞ |
...so the Force required to take an object to or beyond the speed of light is infinite. A black hole has a LOT of gravitational pull, and does assert an enormous force on objects, but the speed of light will never be reached
EDIT: dammit, bikerman beat me to it
I put the calculations in quote tags to make them easier to destinguish and read - and because they are taken in half from my physics book. (i study physics at college
[quote="LukeakaDanish"]Ok...so it sounds like a quite well thought through theory...and there are definitely some clever bits to it however, my problem with it, at the moment, is that any object with a mass can never reach the speed of light.
Here's an attempt at an explanation:
Nice 1....I crashed the 'puter half way through my version so to the victor go the plaudits
Here's an attempt at an explanation:
Nice 1....I crashed the 'puter half way through my version so to the victor go the plaudits
| Quote: |
|
...so the Force required to take an object to or beyond the speed of light is infinite |
But if the masses of both of the black holes are infinite, won't the gravitational force between them become infinite also?
Or does the greater mass caused by faster speed not cause greater gravity?
| ocalhoun wrote: | ||
But if the masses of both of the black holes are infinite, won't the gravitational force between them become infinite also? Or does the greater mass caused by faster speed not cause greater gravity? |
Oohhh...you've found a glitch in the universe...
Cant answer your question...not clever enough
One thing though: To get to the speed of light, you need an unlimited force - which you cant obtain without already being at the speed of light?
...something like that...
| Bikerman wrote: |
| The answer is that they will circle and eventually combine into 1 BH with the solar mass of the two. |
In other words, if two black holes collide you get an even blacker hole.
i'm sorry. >.< i couldn't help it.
| LukeakaDanish wrote: | ||||
Oohhh...you've found a glitch in the universe... Cant answer your question...not clever enough
One thing though: To get to the speed of light, you need an unlimited force - which you cant obtain without already being at the speed of light? ...something like that... |
The mass of a black hole is not infinite.
i'm going to go waaaaay back to basics to explain this, so a lot of this may be stuff you know well. For the sake of simplicity, i've glossed over a lot, though. All of this only applies to non-rotating, non-charged black holes:
What if you threw a ball straight up in the air? It would go up, slow down, stop, then begin to fall back down, right? That's because gravity makes it acelerate downwards. What if you threw it even faster? It would go higher, and take longer to slow down and stop, before finally coming back down. Gravity still makes it accelerate downwards, but when the velocity is higher, it takes longer for gravity to bring it to a stop. If you throw that ball harder and harder, eventually you will throw it so fast (11.2 km/s) that gravity will not be strong enough to pull it back down before it gets away. This is the escape velocity, and you can calculate it with:
where M is the mass of Earth, r is the distance from the center of the Earth, and G is the universal gravitational constant.
Look at that equation. The mass of the Earth doesn't change, and obviously the universal gravitational constant doesn't change, but you can change r simply by going up or down (closer to or farther from the center of the Earth). Of course, you can't go any lower than the Earth's surface or the equation isn't valid any more (because some of the Earth's mass is above you and some is below). As r increases, the escape velocity gets smaller - the higher you go (the farther away from the Earth's center), the easier it is to escape the Earth's gravity. This is very important.
Imagine setting the escape velocity to c, the speed of light, and solving for r. That would tell you how close you have to be to the Earth's center of mass before it is impossible to get away from it. This is called the Schwarzchild radius, and it is a property of every mass. The equation is the same as above, but rewritten the way i described:
The Earth's Swarzchild radius is about 9 mm. That means that if all of the mass of the Earth were compacted to a point at the center, you would be able to get no closer than 9 mm to that center before you could not escape. Even light wouldn't be able to escape at that distance.
But! This result doesn't actually mean anything because the equation makes no sense as soon as you go below the surface of the Earth (remember, you now have some of the Earth's mass above you, and some below). It's interesting, but not real.
The radius of the Earth is around 6400 km, which means that the equations above are meaningless if r is less than 6400 km, and you know that at the Earth's surface, the escape velocity is 11.2 km/s and r is 6400 km. But... just suppose for a second....
Suppose the radius of the Earth were only 1 m, but it had the same mass. That would make it super dense. If you were in orbit 6400 km above that mass, the escape velocity would be 11.2 km. As you get closer and closer, the escape velocity would increase, until it's literally astronomically high. But even at the surface of that super dense 1 m sphere, you could still (theoretically) escape, because the Swarzchild radius is still around 9 mm (although in reality, you'd be torn apart and crushed at the same time, of course).
Now, suppose the radius of the Earth were 9 mm, but it had the same mass. Now it's REALLY super dense. Again, if you were in orbit 6400 km above that mass, the escape velocity would be 11.2 km. As you get closer, the escape velocity increases. At 1 m you can still escape. But when you get to the surface of the sphere, the escape velocity is now exactly c. That means that you can now never escape.
Now suppose the radius of the Earth were 5 mm, but it had the same mass. Everything is the same as before, except now you can cross that 9 mm line and enter the area where the escape velocity is greater than c. What happens there? No one knows. As soon as you crossed the 9 mm line, nothing, not even light, can get out. But the mass of the Earth has not suddenly become infinite. In fact, it's the same mass, just compressed into a smaller volume.
Any object that has a Schwarzchild radius equal to or larger than its physical radius is a black hole.
The physical radius of the Earth is 6400 km, and its Schwarzchild radius is 9 mm. Thus the Earth is not a black hole (thankfully). Similarly, the sun's physical radius is around 0.7 × 10⁶ km, and its Schwarzchild radius is 3 km. You can play with other numbers yourself here: http://hyperphysics.phy-astr.gsu.edu/hbase/astro/blkhol.html
You see? There are really no infinities involved. Just really dense masses.
^I know that black holes do not have infinite mass! However, mass increases with speed. So;
The closer together they get, the more they accelerate towards each other.
The more speed, the more mass they have.
The more mass they have the more force they exert on each other.
The more force they exert on each other, the more speed.
The more speed...
^What I'm wondering is would they hit each other before this lovely little feedback loop causes them to accelerate beyond the speed of light? before they each get to half the speed of light?
Ah, but if m=∞, then F=∞ as well.
I'm thinking that they will not reach the speed of light because in order for the mass to be infinite, they have to first reach the speed of light, and in order to reach the speed of light, the mass must be infinite.
However, I figure they both could get very, very close to the speed of light, say 95% of it. Therefore, their combined speed at impact would be 190% of the speed of light. Now, some particles of them would be flung away at a very high rate of speed by such a powerful impact (remember at this point, you have two already spectacularly huge masses, made far more massive by their speed, and hitting each other at nearly twice the speed of light). Now let's suppose two pounds of material, either Iron (I suppose you'd find that plentiful in very old stars) or, of the pressure was too much for atoms, just a mass of subatomic particles, by random chance absorbs a large amount of the momentum of the impact and is shot off... How fast would it be going? Could it escape the combined gravity of the holes?
The closer together they get, the more they accelerate towards each other.
The more speed, the more mass they have.
The more mass they have the more force they exert on each other.
The more force they exert on each other, the more speed.
The more speed...
^What I'm wondering is would they hit each other before this lovely little feedback loop causes them to accelerate beyond the speed of light? before they each get to half the speed of light?
| LukeakaDanish wrote: | ||
|
To get an object to accelerate, a force must be applied to it. The formula for calculating this force is (in its more complex form):
- meaning the change in (mass * velocity) over a set amount of time. |
Ah, but if m=∞, then F=∞ as well.
I'm thinking that they will not reach the speed of light because in order for the mass to be infinite, they have to first reach the speed of light, and in order to reach the speed of light, the mass must be infinite.
However, I figure they both could get very, very close to the speed of light, say 95% of it. Therefore, their combined speed at impact would be 190% of the speed of light. Now, some particles of them would be flung away at a very high rate of speed by such a powerful impact (remember at this point, you have two already spectacularly huge masses, made far more massive by their speed, and hitting each other at nearly twice the speed of light). Now let's suppose two pounds of material, either Iron (I suppose you'd find that plentiful in very old stars) or, of the pressure was too much for atoms, just a mass of subatomic particles, by random chance absorbs a large amount of the momentum of the impact and is shot off... How fast would it be going? Could it escape the combined gravity of the holes?
Well...even for one nucleon, the mass would be infinite if the speed is c...
So i guess, it still seams improbable that a speed larger than or equal to c could be achieved...
I get "your" dillemma though - maybe someone very smart will tells us what is right?
So i guess, it still seams improbable that a speed larger than or equal to c could be achieved...
I get "your" dillemma though - maybe someone very smart will tells us what is right?
| ocalhoun wrote: |
| ^I know that black holes do not have infinite mass! However, mass increases with speed. So;
The closer together they get, the more they accelerate towards each other. The more speed, the more mass they have. The more mass they have the more force they exert on each other. The more force they exert on each other, the more speed. The more speed... ^What I'm wondering is would they hit each other before this lovely little feedback loop causes them to accelerate beyond the speed of light? before they each get to half the speed of light? |
No, it doesn't work like that. You can't just add speeds like that. Works fine for non-relativistic speeds, but fails as you get close to c.
If you have object 1 travelling left at 0.5 c (both measured from an outside reference), and object 2 travelling right at 0.5 c, an observer on object 1 will measure object 2 as approaching at 0.8 c.
(See: http://en.wikipedia.org/wiki/Velocity-addition_formula or http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/einvel2.html#c2 for a calculator)
Neither object will ever reach the speed of light from any reference point. (Try it: put the speeds as 0.99999 and -0.99999 in the calculator above. The result is still < 1. You can keep going with that for a while until the calculator's rounding errors take over.)
^ There's an excellent movie about that here:
http://video.google.com/videoplay?docid=6322511432077219124&q=relativity+theory
Of course, its doesn't go into great detail (its only 5 minutes), but I think its excellent for understanding the basics...
http://video.google.com/videoplay?docid=6322511432077219124&q=relativity+theory
Of course, its doesn't go into great detail (its only 5 minutes), but I think its excellent for understanding the basics...
I can't give any math (because I'm not like that) but I do know what happens when two black holes collide: they merge. I actually saw this on a TV documentary... The giant black holes at the center of every galaxy (sort of like the galactic version of the sun) were formed by numerous smaller black holes merging together as the small black holes at the center of primitive proto-galaxies ran into each other. Time after time, things simply merged. Nothing all THAT dramatic.
seeing as how the two black holes would need to be very large to achieve this effect i doubt it would ever happen anytime soon if it was possible. to my knowledge 'black holes' have already been known to collide with one another. i dont have an exact referrence at the moment, but i can get one up here as soon as i can. if it is possible it would be kind of intense.
Yes. Large black holes at the center of galaxies were theorized to be product of smaller black holes. EVEN if we may such resulting velocities, only time would bend, but it would not exceed the speed of light.
Only quantum level BH were known to emit matter. BUt that is because of their nonclassical physics.
Only quantum level BH were known to emit matter. BUt that is because of their nonclassical physics.
| kimiku wrote: |
| Yes. Large black holes at the center of galaxies were theorized to be product of smaller black holes. EVEN if we may such resulting velocities, only time would bend, but it would not exceed the speed of light.
Only quantum level BH were known to emit matter. BUt that is because of their nonclassical physics. |
All black holes theoretically emit matter, sorta kinda. Spontaneous generation of particle-antiparticle pairs via vacuum fluctuations happen everywhere, but in most places the effect is statistically cancelled out - in a given area where a billion electrons and positrons are created, they end up mostly annihilating each other so the net amount of particles you observe created is zero.
Not so in the area around a black hole. There a particle-antiparticle pair may be spontaneously generated, but one half of the pair falls into the black hole while the other escapes. Effectively, the black hole is creating matter (by destroying half of it). This is a pretty simplified explanation of Hawking radiation.
As Indi points out, Hawking Radiation is far from simple. In fact it's hard sums.
If anyone wants to go deeper into this and have a crack at understanding what is happening then I've put a recent paper on the subject on my site which you can access below (adobe format)
http://camres.frih.net/resources/GeneralPhysics/blackholes/hawkingradiation.pdf
Regards
Chris
If anyone wants to go deeper into this and have a crack at understanding what is happening then I've put a recent paper on the subject on my site which you can access below (adobe format)
http://camres.frih.net/resources/GeneralPhysics/blackholes/hawkingradiation.pdf
Regards
Chris
Bigger black holl ... so far as I know.
Might they just revolve around each other? like when galaxies collide.
they will circulate like two planets do due to gravitation and their will exist an equilibrium ...............................
to learn more about black holes ..........use Stephen Hawkins Books on this topic
due to relativity we can say that "if two particles move with 0.8*speed of light
in opposite direction then their relative velocity will be only equal to 'speed of
light' but willn't be equal to 1.6*C "
so your concept of particles speed more than C is total f**k
to learn more about black holes ..........use Stephen Hawkins Books on this topic
due to relativity we can say that "if two particles move with 0.8*speed of light
in opposite direction then their relative velocity will be only equal to 'speed of
light' but willn't be equal to 1.6*C "
so your concept of particles speed more than C is total f**k
well, i would like to tell you that when 2 black holes collide, this will what happen:
If the semi-diameter of a sphere of the same density as the Sun were to exceed that of the Sun in the proportion of 500 to 1, a body falling from an infinite height towards it would have acquired at its surface greater velocity than that of light, and consequently supposing light to be attracted by the same force in proportion to its vis inertiae (inertial mass), with other bodies, all light emitted from such a body would be made to return towards it by its own proper gravity. THIS IS A BLACK HOLE.
Although black holes are invisible, the collision of two of them will produce gravitational waves, ripples in the curvature of space, which could be recognized by gravitational-wave detectors. But as of yet, no one has detected a gravitational wave. Effects from the emission of gravitational waves have been observed in binary pulsars, an indirect detection.
To simulate black-hole collisions, numerical relativists, such as Laguna, have excised the singularity — in essence, creating a black hole without a black hole. While this may seem an oxymoron, this "surgical procedure" does not affect the outcome of the simulations as long as it is performed inside the event horizon, in the region that external observers cannot see. Basically, the team is making the math computable. Even so, they rely on a number of interlinked computers running on software they themselves have written.
If the semi-diameter of a sphere of the same density as the Sun were to exceed that of the Sun in the proportion of 500 to 1, a body falling from an infinite height towards it would have acquired at its surface greater velocity than that of light, and consequently supposing light to be attracted by the same force in proportion to its vis inertiae (inertial mass), with other bodies, all light emitted from such a body would be made to return towards it by its own proper gravity. THIS IS A BLACK HOLE.
Although black holes are invisible, the collision of two of them will produce gravitational waves, ripples in the curvature of space, which could be recognized by gravitational-wave detectors. But as of yet, no one has detected a gravitational wave. Effects from the emission of gravitational waves have been observed in binary pulsars, an indirect detection.
To simulate black-hole collisions, numerical relativists, such as Laguna, have excised the singularity — in essence, creating a black hole without a black hole. While this may seem an oxymoron, this "surgical procedure" does not affect the outcome of the simulations as long as it is performed inside the event horizon, in the region that external observers cannot see. Basically, the team is making the math computable. Even so, they rely on a number of interlinked computers running on software they themselves have written.
Black holes colliding... very, very bad. Two gravity sinks in such close proximity - one would have to destabilise the other, unless they were exactly identical in mass and size.
They will make a bigger blackhole. So biger mass,grater gravity & bigger monster. The cosmic monster....
Also another theory,
If each black hole is in a another galaxy, it would create a wormhole.
It sounds nuts, but it is just a small guess, everything can be possible in this level of science.
I think that other people will think the same like me or not?
If each black hole is in a another galaxy, it would create a wormhole.
It sounds nuts, but it is just a small guess, everything can be possible in this level of science.
I think that other people will think the same like me or not?
| Lord Klorel wrote: |
| Also another theory,
If each black hole is in a another galaxy, it would create a wormhole. It sounds nuts, but it is just a small guess, everything can be possible in this level of science. I think that other people will think the same like me or not? |
Err...how would they collide ?
C.
Not much more is expected than the expansion of the schwarzschild radius (the radius in which light cannot escape). Spacetime would thus be bent over a larger distance, but would change little to the pointlike-structure of the black hole itself. In an analogy, the bend of the spacetime would not be "deeper" after the collision, just spread over a larger area.
The events leading up to the actual collision may though be different. Objects that are attracted by black holes get spun up and heated in such a way that they eject high energy rays often seen in "jets" perpendicular to the black hole. I wonder what kind of energy releases you'd see when one black hole is attracting another one...
The events leading up to the actual collision may though be different. Objects that are attracted by black holes get spun up and heated in such a way that they eject high energy rays often seen in "jets" perpendicular to the black hole. I wonder what kind of energy releases you'd see when one black hole is attracting another one...
| Detremmerie wrote: |
| Not much more is expected than the expansion of the schwarzschild radius (the radius in which light cannot escape). Spacetime would thus be bent over a larger distance, but would change little to the pointlike-structure of the black hole itself. In an analogy, the bend of the spacetime would not be "deeper" after the collision, just spread over a larger area.
The events leading up to the actual collision may though be different. Objects that are attracted by black holes get spun up and heated in such a way that they eject high energy rays often seen in "jets" perpendicular to the black hole. I wonder what kind of energy releases you'd see when one black hole is attracting another one... |
That would require a S-R of a Galactic Distance (the BHs being in different Galaxies). Without doing any math I have a feeling that we would be talking about more mass than is physically available in the known Universe....could be wrong of course...
Chris.
Do black holes exist?
We think we do, but we really don't know
It's like an atom, we really cannot know what it looks like, but we have a pretty darn good idea on what it looks like
But if two of them collided, it could possibly merge two times and I really don't know what might happen
We think we do, but we really don't know
It's like an atom, we really cannot know what it looks like, but we have a pretty darn good idea on what it looks like
But if two of them collided, it could possibly merge two times and I really don't know what might happen
| coolsmile wrote: |
| Do black holes exist?
We think we do, but we really don't know It's like an atom, we really cannot know what it looks like, but we have a pretty darn good idea on what it looks like But if two of them collided, it could possibly merge two times and I really don't know what might happen |
Yes, they exist. Do we know they exist? Yes, we do, in so far as we know anything exists. If you want to debate whether we can know anything at all, you should be in the philosophy forum. While it's true we can't see a black hole itself, we can see the effects the black hole has on things around it that cannot be explained by anything else conceivable other than a black hole. If that's not enough evidence for the existence of a black hole, then you must also have difficulty believing in things like air, electricity and gravity.
Atoms don't "look like" anything, because on that level light is meaningless. We have working models that describe their behaviour and structure very accurately, but you can't just get a big-ass lens and focus it on a single atom and "see" it.
If two black holes collided you'd get a bigger black hole. That's about it.
| coolsmile wrote: |
| Do black holes exist?
We think we do, but we really don't know |
There is little doubt on the matter:
http://cosmology.berkeley.edu/Education/BHfaq.html#q7
http://www.space.com/scienceastronomy/astronomy/death_spiral_010111.html
http://www.damtp.cam.ac.uk/user/gr/public/bh_obsv.html
http://en.wikipedia.org/wiki/Cygnus_X-1
http://news.utoronto.ca/bin/bulletin/nov10_97/art4.htm
Here is a schematic for 20 binary-BH pairs, taken from a Yale document
http://mintaka.sdsu.edu/faculty/orosz/web/schem.gif
Regards
Chris
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