theoretical - sci-fi thing - power from black holes?

[tommo123]

How in theory could you gain power from black holes? I thought they basically sucked everything in. Or is it 'hawking radiation' or whatever they think black holes spew out that they use for power?

a bit random i know

 

[William Gaatjes]

Originally posted by: tommo123
How in theory could you gain power from black holes? I thought they basically sucked everything in. Or is it 'hawking radiation' or whatever they think black holes spew out that they use for power?

a bit random i know

Maybe you could use the plasma jets from a blackhole.
There is a lot of energy in that plasma , but until we become a type III civilization that will not happen. That plasma would destroy us.

Relativistic_jet

Kardashev_scale





EDIT: Added link.

 

[tommo123]

read that scale thing on wiki aaages ago. forgot about that. wonder if we'll survive that long

 

[William Gaatjes]

Originally posted by: tommo123
read that scale thing on wiki aaages ago. forgot about that. wonder if we'll survive that long

If we all just start to agree that :

An honest day work is a good thing.
That a life is more important then money.
That a friend is more important then money.
That getting positive critique is a compliment and not something to be ashamed off.
That if you believe or not, we are all the same and humanity combined can conquer
every disaster.
That we must always look after each other and be cautious of greed and corruption.
That man and woman are meant to be different as to better complement one and other.
That people realize that what negative thing they do, lives on beyond tomorrow in their offspring.

I can go on forever...
Maybe an idea that other people fill it in with positive phrases. :laugh:

Then yes, we might actually survive that long .

 

[EricMartello]

How in theory could you gain power from black holes? I thought they basically sucked everything in. Or is it 'hawking radiation' or whatever they think black holes spew out that they use for power?

a bit random i know

The plasma jets which SOME black holes eject are not created by the black hole itself; those jets usually occur when a black hole sucks up a gas cloud or star.

From what I gather, black holes are not actually holes so much as they are super-dense orbs of stellar matter. Logically that is what they would be since they are imploded stars. So basically you have the entire mass of a star in something the size an asteroid; the "black matter" which makes up a black hole is incredibly dense and most likely has unique and unusual properties which we are totally unfamiliar with.

I would say that black matter is not much good for extracting energy but the actual black matter itself could be used to make something that can contain a sustained fusion or antimatter reaction...and not a small scale reaction, think more like "star level" power that you can fit in your pocket. Ok, maybe not your pocket but definitely in a modestly sized warehouse.

If you could build a reactor using "black matter" for the reaction chamber, you could conceivably have the power output of the sun in a reactor that is no larger than our current nuclear reactors, possibly even smaller. As a side benefit, the reaction chamber could also act as the catalyst for the sustained reaction.

Why would we want this kind of reactor? Such a device would allow us to terraform rogue planets which are not part of any solar system, or the reactor could be used to terraform and colonize planets which are not in the "goldielocks zone" within a star system.

Personally, I wouldn't put the reactor on the planet; i'd set it up in fixed orbit over the planet so that it acts like a portable sun.

 

[Biftheunderstudy]

Eric:
Your statement that the jets from black holes (and indeed forming starts) does not come from the black hole itself is correct. The jets origins lie in the accretion disc + magnetic field surrounding the star/BH though this is a young topic in theoretical astronomy and the mechanism is far from understood.

You go off on a bit of a weird tangent then. The black hole part of the black hole is a singularity. This means that the size goes to zero and thus the density goes to infinity -- note that this is not just a mathematical singularity but a real physical one. Surrounding the black hole is a zone after which all trajectories go into the singularity, this is the event horizon, the point of no return, schwarzschild radius etc...

Since the black hole has no forces powerful enough to support the matter from collapsing, the state of matter for a black hole is probably not a good question. Black holes can be thought of as elementary particles in fact -- the only things that uniquely identify them are mass, spin, and charge.


Now, to input some thoughts into the original question.
Since the only thing black holes have is mass spin and charge the only way you can get energy from them is through these things. To get energy from mass you need something like a like a hydroelectric dam, matter falling down into the potential well and generating power -- not very feasible since its hard to get that power anywhere. Charge could work but it might be a bit hard to do. One proposal that I read somewhere was to extract angular momentum from a spinning black hole. I forget the details but it involved dumping matter onto the black hole to transfer angular momentum from the black hole.

 

[William Gaatjes]

Eric:

This means that the size goes to zero and thus the density goes to infinity -- note that this is not just a mathematical singularity but a real physical one.

A real physical one ?
has this ever been proven ?

 

[Biftheunderstudy]

Mathematically at least
It would be a bit hard to prove any other way....

 

[EricMartello]

A real physical one ?
has this ever been proven ?

No it hasn't been proven and if you think about it, it is a flawed theory. Since black holes are forming from collapsing and imploding stars, the matter that makes up the star is compressed and that defines the "mass" of the black hole matter. To say a black hole is "infinitely dense" would mean that the star that formed the hole was infinitely massive. Furthermore, if black holes were truly "infinite" then there couldn't be different types of black holes - they'd all be identically infinite. Not the case - because there is apparently a "super massive" black hole in the center of our own galaxy.

If a black hole has "infinite" density and mass, how can one be more massive than the other? Once you use the concept of infinity to make a theory work, mathematically or otherwise, you render it invalid. If you can't explain it any other way then keep thinking.

On a side note: You can see a black hole that stalled "mid way" during implosion...it becomes a neutron star. The matter that makes up a neutron star is extremely dense and could be used to construct a reactor as I said in my other post, but the "black matter" that makes up a black hole would be ideal if you wanted to make a portable reactor that puts out star-levels of power.

 

[Biftheunderstudy]

Ok, here is a bit of a stellar structure lesson.

Stars are in a balance between outward pressure and an inward force of gravity. The outward pressure is caused by fusion of hydrogen into helium. There are a host of 'pressures' that can help support the star.

As a star ages it develops a core of helium and depending on the mass this can ignite helium burning to convert to higher mass elements. If it doesn't have sufficient mass to collapse further and create the temperatures needed to burn carbon, you are left with a carbon-oxygen-nitrogen core that can't undergo fusion anymore. So what keeps the star from collapsing further? Electron degeneracy pressure. The pauli exclusion principle says that electrons (fermions actually) can't occupy the same state, this means that they exert a force to keep them from getting too close to each other and this force acts as a pressure. It is this pressure that keeps a white dwarf from collapsing. Wikipedia has some more info on this.

Next in line we have neutron stars. Massive stars can fuse successively heavier elements until they reach iron. Iron is special because it is the breaking point between releasing energy from fusion and actually costing energy to fuse iron (heavier elements need to fission to release energy). Once the star has an iron core it is too massive to be held up by the electron degeneracy pressure so it continues to collapse. When the density reaches a certain point it is energetically favorable to inverse beta decay. This is when an electron and a proton merge to form a neutron and a neutrino (a neutrino burst was detected in 1987 that correlates with supernova 1987a). Now it is neutron degeneracy pressure that can hold the star up against collapsing further.

Finally if the star is even more massive the same thing might happen with quarks when the neutron breaks down but this is still very theoretical and observations haven't found any solid candidates for quark stars.

The final stage then is a black hole. This is when the neutron degeneracy is not enough to support the surrounding star and it continues to collapse. This is not to say that there isn't some sort of exotic matter state that it collapses to, just that it would be hidden behind the event horizon. There is a pretty big philosophical debate whether there can be a so called naked singularity, that is a singularity not obscured by an event horizon.

This is the whole point however, because the singularity is hidden behind the event horizon it is ok that the density can reach an infinite value -- if you are worried about infinities try looking at the standard model and quantum gravity...
In fact, if you take the schwarzschild radius for the supermassive black hole at the center of the galaxy and compute the density for the entire thing you get a number that is less dense than water. You probably wouldn't even notice falling into one of them.

I hope this helps.

 

[EricMartello]

This is the whole point however, because the singularity is hidden behind the event horizon it is ok that the density can reach an infinite value -- if you are worried about infinities try looking at the standard model and quantum gravity...
In fact, if you take the schwarzschild radius for the supermassive black hole at the center of the galaxy and compute the density for the entire thing you get a number that is less dense than water. You probably wouldn't even notice falling into one of them.

I hope this helps.

You could have attempted to answer my rhetorical question to save yourself a bit of typing:

If a black hole is truly a "singularity" and has INFINITE density and mass, then there can only be ONE type of black hole. It would not be possible for there to be a "super massive" black hole and a "normal" black hole because both are equally infinite. Apparently that is not the case, as not all black holes are equal in their mass.

Spouting little understood quantum theory is hardly going to support your position. It seems like quantum theory is the scientific way of attributing something to a deity without sounding religious.

If you want to know why infinity as a solution FAILS, just imagine an infinite number line. No matter how far you move in either direction on the number line you will always be at position zero. Infinity renders math useless when attempting to describe something like a black hole because it reduces it to an "all or nothing" type of solution.

A singularity can either exist, or not exist - there cannot be multiple "grades" of singularities and we have already observed that black holes are not all identically massive. They are not singularities.

 

[William Gaatjes]

You could have attempted to answer my rhetorical question to save yourself a bit of typing:

If a black hole is truly a "singularity" and has INFINITE density and mass, then there can only be ONE type of black hole. It would not be possible for there to be a "super massive" black hole and a "normal" black hole because both are equally infinite. Apparently that is not the case, as not all black holes are equal in their mass.

Spouting little understood quantum theory is hardly going to support your position. It seems like quantum theory is the scientific way of attributing something to a deity without sounding religious.

If you want to know why infinity as a solution FAILS, just imagine an infinite number line. No matter how far you move in either direction on the number line you will always be at position zero. Infinity renders math useless when attempting to describe something like a black hole because it reduces it to an "all or nothing" type of solution.

A singularity can either exist, or not exist - there cannot be multiple "grades" of singularities and we have already observed that black holes are not all identically massive. They are not singularities.

All i know is that a lot of natures laws ( i would not be surprised if all of them have this characteristic) are based on a tangent function. You can reach it but you never get there. That is unless you stop being part of the universe.
Then you do not have to obey natures laws since the universe is existing only because of these laws. Our universe does not make the laws. It is the laws that make our universe.

It is like you want to reach a temperature of zero but you never get there. Or you want to reach the maximum speed of light but you can never reach that maximum speed.
If a singularity truly exists. It has the same problem. It still has to obey natures laws. It may be way further up that tangent line but it is still up that line. Now the real question is, what causes that tangent function in natures laws ?

http://images.google.nl/imgres?imgu...hl=en&sa=N&num=10&um=1&ie=UTF-8&oe=UTF-8&um=1

 

[Gibsons]

You could have attempted to answer my rhetorical question to save yourself a bit of typing:

If a black hole is truly a "singularity" and has INFINITE density and mass, then there can only be ONE type of black hole. It would not be possible for there to be a "super massive" black hole and a "normal" black hole because both are equally infinite. Apparently that is not the case, as not all black holes are equal in their mass.

Spouting little understood quantum theory is hardly going to support your position. It seems like quantum theory is the scientific way of attributing something to a deity without sounding religious.

If you want to know why infinity as a solution FAILS, just imagine an infinite number line. No matter how far you move in either direction on the number line you will always be at position zero. Infinity renders math useless when attempting to describe something like a black hole because it reduces it to an "all or nothing" type of solution.

A singularity can either exist, or not exist - there cannot be multiple "grades" of singularities and we have already observed that black holes are not all identically massive. They are not singularities.

If a black hole has finite mass and zero volume (not "very small," zero) then the density would be infinite, right? Dividing by zero is always messy. But this certainly allows black holes of different mass, but all with infinite density.

 

[WildW]

To go back to the original question of power from black holes, it occurred to me that you ought to be able to slingshot some object around it to gain speed, but wikipedia ( http://en.wikipedia.org/wiki/Gravity_assist ) seems to think the universe has a get-out clause to stop that. . .

"Another theoretical limit is based on general relativity. If a spacecraft gets close to the Schwarzschild radius of a black hole (the ultimate gravity well), space becomes so curved that slingshot orbits require more energy to escape than the energy that could be added by the black hole's motion."

It does however go on to say. . .

"A rotating black hole might provide additional assistance, if its spin axis points the right way. General relativity predicts that a large spinning mass produces frame-dragging — close to the object, space itself is dragged around in the direction of the spin."

All this is going beyond my understanding of slingshot orbits, which is limited to rescuing whales from 20th-century San Francisco.

 

[EricMartello]

If a black hole has finite mass and zero volume (not "very small," zero) then the density would be infinite, right? Dividing by zero is always messy. But this certainly allows black holes of different mass, but all with infinite density.

Yes, your statement could explain the existence of a black hole with infinite density and limited mass, but it doesn't cover all of the bases. While the forces that create a black hole are great, for gases and other stellar matter to be compressed into something that is infinitely dense, the force acting upon them to form the compression would need to be be equally "infinite"...something that doesn't seem likely given the finite quantity of mass within the object.

Other issues with infinitely dense matter:

- It would occupy no space.

- It would have no temperature (no heat whatsoever)

- All of the matter that created it would somehow become one "particle" of sorts...i.e. it vanishes.

- If the particle comes into contact with other matter then it should grow like a snowball, but black holes with plasma gets release matter - something that should not happen if there is an "infinite" force at work.

 

[Biftheunderstudy]

Yes, your statement could explain the existence of a black hole with infinite density and limited mass, but it doesn't cover all of the bases. While the forces that create a black hole are great, for gases and other stellar matter to be compressed into something that is infinitely dense, the force acting upon them to form the compression would need to be be equally "infinite"...something that doesn't seem likely given the finite quantity of mass within the object.

Again, this is not correct. I outlined how a star is supported through pressure, that pressure is finite and a particular value based on the number of the specific particle in the star. If the star has too much stuff in it then the gravitational force is larger than the pressure force and the star collapses. We have ample evidence for white dwarfs and neutron stars that agree quite well with our assumptions. If there is another kind of pressure able to support the star after neutron/quark degeneracy it would be too late to keep the stars radius beyond the schwarzschild radius where it becomes a black hole. Nowhere does this need an infinite force, only gravity. Infinite density =/= infinite force.

Again, the gas and stellar matter are converted into other forms of matter which can occupy a smaller and smaller volume. Eventually even this is not enough and the whole thing collapses to a point -- thus the infinite density.

Other issues with infinitely dense matter:

- It would occupy no space.

Yes that is right. The event horizon is finite though.

- It would have no temperature (no heat whatsoever)

There are varying interpretations and theories on this. The infamous Hawking Radiation is associated with this question.

- All of the matter that created it would somehow become one "particle" of sorts...i.e. it vanishes.

That it sort of becomes a really heavy particle is correct. Again this aspect is open to some debate. Since the only things which define a black hole uniquely are its mass, spin(rotation), and charge they can be thought of as elementary particles. (electrons for instance have mass, charge, spin and also have no size)

Why would it behaving like a particle mean that it vanishes?

- If the particle comes into contact with other matter then it should grow like a snowball, but black holes with plasma gets release matter - something that should not happen if there is an "infinite" force at work.

Again, first part is true but the second part does not follow. Anything that goes past the event horizon does not come out and is added to the black hole mass.
Once again the relativistic jets from black holes do not come from the black hole but rather the disk of matter surrounding the event horizon that is falling in on it.


Back to the original topic though.
One of the interesting things about black holes is that if you solve Einsein`s equations for a charged/rotating black hole you get some very interesting features of the space/time and event horizon. A spinning black hole in particular might allow a system to take angular momentum from the black hole (to be turned into energy of course).

I recommend looking up something called an ergosphere - I think Wiki might have some good info on this, facinating read anyhow.

 

[sjwaste]

The thing that always fascinated me about black holes was that you'd have matter, which does have size, "falling in" and all of a sudden not occupying any space at all.

For instance, do quarks have size (2-dimensional area or 3-dimensional volume)? If so, how do they, or the things made of them -- protons, neutrons, etc -- lose that when they collapse into a black hole? I suppose like anyone else, I have trouble with infinities because on the macroscopic level, we're talking about cramming 1001 1mL cubes into a 1L container. It wouldn't fit macroscopically. How does it fit?

 

[EricMartello]

Again, this is not correct. I outlined how a star is supported through pressure, that pressure is finite and a particular value based on the number of the specific particle in the star. If the star has too much stuff in it then the gravitational force is larger than the pressure force and the star collapses. We have ample evidence for white dwarfs and neutron stars that agree quite well with our assumptions. If there is another kind of pressure able to support the star after neutron/quark degeneracy it would be too late to keep the stars radius beyond the schwarzschild radius where it becomes a black hole. Nowhere does this need an infinite force, only gravity. Infinite density =/= infinite force.

You are right that we're just making assumptions here...but you seem to miss the point about compressing matter to a point where it is infinitely dense. The gravitational forces that act upon a star are finite, just as the pressures that keep it "alive" are also finite. The act of imploding does not or should not increase the gravitational forces acting on the matter...that is why it cannot compress it to an INFINITE density. Or maybe it can...I dunno, I've never been inside a black hole.

Again, the gas and stellar matter are converted into other forms of matter which can occupy a smaller and smaller volume. Eventually even this is not enough and the whole thing collapses to a point -- thus the infinite density.

What you are suggesting is not implosion of matter; what you are suggesting is that the matter moves into another phase or possibly another dimension, because infinitely dense matter CANNOT exist in THIS universe.

That it sort of becomes a really heavy particle is correct. Again this aspect is open to some debate. Since the only things which define a black hole uniquely are its mass, spin(rotation), and charge they can be thought of as elementary particles. (electrons for instance have mass, charge, spin and also have no size)

It's not really a particle if it is infinitely dense. See below.

Why would it behaving like a particle mean that it vanishes?

It's not a particle, matter that is truly of infinite density ceases to exist in this realm. We cannot "touch" it, see it or otherwise detect it. Yes, we can detect the turbulence its presence creates, but the so-called singularity itself is no longer part of this universe (if we are to believe it is infinitely dense matter, which I am not sold on).

Again, first part is true but the second part does not follow. Anything that goes past the event horizon does not come out and is added to the black hole mass.
Once again the relativistic jets from black holes do not come from the black hole but rather the disk of matter surrounding the event horizon that is falling in on it.

Hmmmmm...I dunno. The jets look more like they are shooting out than skimming off the event horizon. We assume nothing an escape a black hole but maybe there is something that escapes and we just haven't noticed yet.

The thing that always fascinated me about black holes was that you'd have matter, which does have size, "falling in" and all of a sudden not occupying any space at all.

For instance, do quarks have size (2-dimensional area or 3-dimensional volume)? If so, how do they, or the things made of them -- protons, neutrons, etc -- lose that when they collapse into a black hole? I suppose like anyone else, I have trouble with infinities because on the macroscopic level, we're talking about cramming 1001 1mL cubes into a 1L container. It wouldn't fit macroscopically. How does it fit?

One thing you may want to think about is "time dilation". Ahem...I do not think that time exists, but for the sake of argument I'll assume it does.

As you approach the speed of light, the apparent passage of time slows down. Theoretically, if you move at the speed of light time stops entirely.

Matter which falls into a black hole is accelerated to velocities near the speed of light, and because of that, whatever goes into a black hole essentially stops...at least 99% stops.

Suppose you could jump into a black hole for a second and then come right out. What seemed like a second to you while you were in the black hole could have been eons to someone outside the black hole. Interesting...

 

[Biftheunderstudy]

Please just look up some other elementary particles and get back to me on the infinite density no radius concept. Its really not as dire as you suggest.

If you truly believe that quantum mechanics is wrong and these particles don't exist etc., and I stress the word believe, then I can do nothing to sway your faith. You'll have a lot of work ahead of you if you intend to come up with a new theory of quantum gravity and I wish you luck.

For the record I think the original question has been answered and now its just a philisophical debate.

 

[EricMartello]

If you truly believe that quantum mechanics is wrong and these particles don't exist etc., and I stress the word believe, then I can do nothing to sway your faith. You'll have a lot of work ahead of you if you intend to come up with a new theory of quantum gravity and I wish you luck.

For the record I think the original question has been answered and now its just a philisophical debate.

I get it, you believe in Quantum Theory.

 

[KIAman]

Infinite is mathematical. Mass/0 volume = infinite.

Once we identify the property/particle/effect/doohicky that makes particles not take up the same position in space/time and prove that it is either negated/removed/overpowered in a black hole, we will never know.

 

[silverpig]

So much fail.

 

[tommo123]

this has been an interesting read guys

ta

 

[sjwaste]

So much fail.

I thought I asked at least a reasonable question. I'm not sure that there's a good answer for it, but it's not way out there.

 

[sjwaste]

Infinite is mathematical. Mass/0 volume = infinite.

Once we identify the property/particle/effect/doohicky that makes particles not take up the same position in space/time and prove that it is either negated/removed/overpowered in a black hole, we will never know.

Yeah, I just can't get my head around how particles with volume suddenly can all occupy the same point in space and in effect, lose their volume. Is it just that the elementary particles are converted to pure energy in the black hole and we're talking about the accretion of a black hole's mass as an energy-equivalent?