A Black Hole's Spinning Heart of Darkness 121
sciencehabit writes "Like all invisible things that are only partly understood, black holes evoke a sense of mystery. Astronomers know that the tremendous gravitational pull of a black hole sucks matter in, and that the material falling in causes powerful jets of particles to shoot out of the hole at nearly the speed of light. But how exactly this phenomenon occurs remains a matter of conjecture, because astronomers have never quite managed to observe the details – until now. Astrophysicists have taken the closest look to date at the region where matter swirls around a black hole. By measuring the size of the base of a jet shooting out of the supermassive black hole at the center of the M87 galaxy (abstract), the researchers conclude that the black hole must be spinning and that the material orbiting must also be swirling in the same direction. Some of the material from this orbiting 'accretion disk' is also falling into the black hole, like water swirling down a drain."
Fascinating (Score:5, Interesting)
I probably won't live to see it but I am looking forward to when we can directly observe in more detail the area surrounding the event horizon of black holes. There is so much we do not understand about the Universe and overall cosmology, but black holes by their very nature will probably be one of the last frontiers as we continue to peel back the layers of knowledge in our understanding of the nature of the Universe as a whole.
There are also potentially practical applications given far greater technology than we have now. Imagine using black holes to generate energy, or as massive particle accelerator laboratories!
Re:Fascinating (Score:4, Interesting)
Basically a continual increase in material density from neutron star densities to the point where gravitational forces are capable of attracting photons and other larger classifications of matter, either resulting in the fusion of matter to ever increasing densities of conventional matter or recombination of subatomic components in such a fashion of maximum compression density.
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Do you think that black holes receive a notably more 'mystical' treatment than most other scientific phenomena that can only be usefully talked about in terms of fairly high level math? They certainly get their share of time whenever a SyFy special needs some sort of treknobabble to work with; but by the standards of things that eat photons and defy direct observation they seem to be doing reasonably well...
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phenomena that can only be usefully talked about in terms of fairly high level math?
A black hole is a ball of stuff with an extremely high density and an extremely small volume, which exerts an extreme gravitational pull that not even light can escape.
There, no high level math, and no mysticism, and only minor inaccuracies (volume vs mathematical point).
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I believe the idea of black holes largely developed as a result of Einstein's General Theory of Relativity. In particular, the Schwarzschild solution to the equations Einstein proposed described a stationary black hole, and the Kerr solution described a rotating black hole. Several others contributed. The math associated with the General Theory of Relativity is fairly dense IMHO, with things like tensor calculus that are rarely addressed until graduate level classes.
We only get simple math if we apply Ne
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Any mathematics, sufficiently advanced, is indistinguishable from magic.
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To me, I would think it suggests that high-intensity fields, in this case gravitational, can affect matter. Look at it from the opposite end of scale. Lets assume we have a point generating a magnetic field, the space surrounding that point can then be filled with free-floating, very fine iron particles. Ramp up the intensity of the field and set it spinning, it *will* affect the iron particles in the direction of its rotation, which would drag the particles around it.
At least, it sounds plausible. :D
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Wow! You totally stole this from Will Wheaton off TNG. Ok, not really, but have you considered writing?
Re:Fascinating (Score:4, Interesting)
The media and a large percentage of the population treat *everything* with a degree of 'mysticism'. Anything that can't be understood in a sentence becomes ghosts, psychic phenomena, "god's hand", etc. etc.
Trained careers like medicine, law, and science become overly dramatic and so highly fictionalized in entertainment that the people who relate to the statement above assume that crimes really are solved in an 8 hour shift, deathly illnesses can always be cured with a single injection in the way we might treat something with epinephrine, and that all physics can be described in a few phrases by Deepak Chopra.
And there's a high level of resistance to combating that 'mysticism'.
Even recently I encountered someone who said that psychics/mediums are frauds... except HER medium...
Sigh.
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Ha! "HER medium" must of been one of those certified psychics!
Re:Fascinating (Score:5, Informative)
It isn't really physically possible (at least, not so far as we know) for a black hole to be considered as a solid physical body. You see, the event horizon isn't the only place where the gravity prevents matter from escaping. Gravity increases until you hit the "outer" part of any body, which means if we assume for a second the event horizon occurs outside all the matter of the former star (which it does), gravity will be slightly more intense inside the horizon. That means that as you travel into the black hole until you reach the outer limit of the physical object itself, gravity will still increase and retain the property of inescapability. What that means is the outer shell of matter can't interact with everything inside, so the normal pressure from electromagnetic and nuclear forces can't keep the outer shell from collapsing inwards (the force literally can't push outwards, since gravity pulls it back).
That means the outer layer of matter will always collapse inwards, closer to the center, and as that happens, the body becomes more dense and the place where gravity forms a horizon extends ever closer to the center of the black hole. Normally, gravity would decrease after you entered the physical body, so near the center of the black hole there should still be a solid physical body where gravity is less than that required to form a horizon, but as the outer layer of the black hole continually falls downwards (it literally can't do anything else), the space near the center where the black hole retains normal physical properties of a star should diminish to nothing.
Another fascinating thing is that at the very center, there should be no gravity at all, by the simple rule of symmetry. But the black hole is ever shrinking towards that spot, so that the density approaches infinity and the entire matter of the star becomes condensed into a point with infinite gravitational force. So the center should also end up with infinity gravity. Which is impossible, or should be. That's why black holes are and always will remain a huge mystery, barring some incredible new scientific revelation that overturns the entire theory of... well, nearly everything.
In other words, for black holes to be treated as solid physical objects, a new force that defies the theory of general relativity (it would have to travel faster than light to allow the matter towards the center of the hole to interact with the matter towards the outer part of the hole) would need to be discovered. And that seems unlikely, although not impossible by any means.
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Today's black holes allow for âoeevaporationâ and the making of âoejetsâ.
Jets aren't really escaping the black hole, that matter never actually fell in. And if by evaporation you mean Hawking radiation, those particles were never inside the black hole either, but they do steal energy, but not information.
Re:Fascinating (Score:5, Insightful)
The jets don't come from inside the black hole at all, they are a result of the interaction of the black hole and the disk of matter falling into it. The exact mechanism for their production isn't certain yet, but the simple explanation is that as the matter gets close to the disk, it spins faster and faster while losing energy (since it is falling into a negative gravity well) which can be focused into some few particles (through magnetic effects or possible relativistic "frame dragging") that are then propelled outwards well before they reach the event horizon. The evaporation is more complex and I don't understand it so I won't try to explain it.
Attempting to explain the universe through electro-magnetism alone is... a useful exercise, but also really not true, and demonstrably so. Gravitation effects are radically different from electrical ones. You can alter electrical theory to fit the observations, but only if you introduce arbitrary new rules and exceptions, which is, if not exactly forbidden in science, at the least extremely questionable (and the more complexities you have to introduce the less likely your theory is to be accurate). Gravitational theory, on the other hand, proceeds from and naturally fits with the observations. Now, it is well known in physics that our understanding of gravity is incomplete (classical and quantum theories do not agree, for one thing, despite both seeming to be true on their respective scales), but to argue that because gravity is "weak" it cannot also be the strongest force en masse (so to speak) is, well, faulty logic. There are numerous examples of weak things aggregating to provide effects well outside their individual strength. When we say electrical forces are "stronger" than gravity, we mean only on a certain scale (atomic, to be specific). Over they scale of a few feet, the nuclear force is nonexistent, despite the fact it is even stronger than the electrical force on small scales.
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Unlike the nuclear force, both gravity and the electrical force operate over cosmic distances. If this were not so, we would not be able to measure electromagnetic effects such as light and magnetic fields. Furthermore, the rules that are applied to electrical interactions here on earth, are exactly the same rules that will explain spinning galaxies, novas and supernovas, immense energy outbursts, pulsars and the behavior of the sun. No new rules need to be invented, but only the application of electrical
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Furthermore, the rules that are applied to electrical interactions here on earth, are exactly the same rules that will explain spinning galaxies, novas and supernovas, immense energy outbursts, pulsars and the behavior of the sun.
Most cosmological and astrophysical models are using the same general relativity rules that are examined and tested right on Earth. If you want to argue it is stupid to assume the same GR rules apply to astrophysical cases without any evidence to the contrary (when there is actually evidence for, with those computer models correctly predicting various measurements), then it would likewise be stupid to assume E&M rules scale up to scales we can't test on Earth. And I said most models, because there are
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Are you saying that the rules of GR and the rules of E&M are in conflict? What I am saying is that most of the universe is highly electrically charged and therefore dominated by the electromagnetic effects. Only where things are nicely neutral, such as here on earth fortunately for us, does gravity predominate.
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Because gravity is so weak, it is very hard to learn much about it. Gravitational waves have been postulated for a long time, but have never been found despite massive expenditures to do so. Electromagnetic waves on the other hand are ubiquitous right here at home. We make use of them every day. Electrical phenomena, such as the electromagnetic radiation we receive from the depths of space, obey the laws of electricity, not gravity. All of the energetic radiation we receive is ELECTROMAGNETIC. Gravity, eve
Re:Fascinating (Score:5, Interesting)
Warning! The above post is an electric universe/plasma cosmology theorist spouting off. They believe that the sun is a giant ball of iron powered by electric currents flowing through space. The whole thing is pretty wacky and is basically a conspiracy theory/collective schizophrenic delusion. You've heard it all before. They think all the so-called "scientists" are either part of a big coverup or are just complete and total fools who don't understand anything whereas they, the electric universe theorists, are the truly intelligent and enlightened.
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The beliefs of “gravity only” cosmology are founded almost exclusively on computer modeling. Some parts of the electric universe theory can be verified experimentally right here on earth in the laboratory. In the electric universe model, electricity and gravity work together to explain observations without resorting to computerized fiction.
And out comes the part about astrophysicist ignoring electromagnetism. This is the part of electric universe fans that really grinds my gears and clearly suggests they have never actually looked into any astrophysics research. It is as naive as trying to claim astronomers have never looked at or thought about stars.
And I don't think you know what a computer model actually does, especially in the fields of astronomy or physics. Those computer models are just solving equations that cannot be solved analyti
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black holes aren't fictitious, purely mathematical constructs.
Look in the center of your own galaxy. It's not even that complex, it's just an out of control gravity well that drags complex matter in and crushes it down to it's minimal components. (radiation) It's not much more complex than that.
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black holes aren't fictitious, purely mathematical constructs.
Look in the center of your own galaxy. It's not even that complex, it's just an out of control gravity well that drags complex matter in and crushes it down to it's minimal components. (radiation) It's not much more complex than that.
We don't KNOW what is at the center of our galaxy. Because of the motion of the stars in the galaxy, a theory has been developed that requires black holes, as well as dark matter and energy, in order to explain the motion of the stars and the rotation of the galaxy as a whole according to what we think we know about gravity. If you add in the effects of electricity and magnetism, then the motion of the galaxy can be explained much more simply, without resorting to never discovered or observed purely mathem
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Since when are accretion disks something other than effects of theorized black holes that have never been shown to exist? Conditions in the center of our galaxy, where black holes supposedly exist, are very much different than an our relatively peaceful part of the galaxy. Black holes are theoretical, mathematical concepts that have no existence anywhere in the real world, even in the center of the galaxy. Extreme electrical effects can be shown to account for all the phenomena that are currently attributed
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Gravitational lensing has been observed. That should be all it takes for you to realize how massively wrong your statements are.
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What has been observed is that light from a distant star is deflected when it passes near another star such as our sun. That this is due to gravity is only an INTERPRETATION of this observation. Since light is an electromagnetic phenomena, it stands to reason and is much more likely that powerful electric fields and electric currents associated with an electrically powered sun would also deflect a light ray that comes close to the sun.
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When light is refracted in a prism for example, what is really happening at the subatomic level? Is the electrical and the magnetic component of the light not interacting with similar components and charges? If that is so, and I believe it is, then why could not powerful electric currents surrounding the sun, as well as the incredibly powerful magnetic fields also affect light's path? Don't forget, the angle through which light is bent passing the sun is very small and the volume through which that light
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As far as we know, only objects that have mass are affected by gravity. Does electromagnetic radiation possess mass? If not, then the gravity-based bending of starlight, despite your complicated explanation is null. Because gravity is such a weak force, we know very little about it. We are much more familiar with the 39 orders of magnitude greater force of electricity. At CERN and elsewhere, scientists are still trying to figure out how exactly mass, acceleration and gravity are interrelated.
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[...] the electrical force, which is 39 orders of magnitude greater than gravity.
Where are you getting this from? Assuming metric units (I hope you're not doing physics with imperial) neither the difference between coulombic and gravitational constants nor the difference between charge and mass of a proton (the next -place I'd expect one to get that difference from). Regardless, claiming such a difference is a pointless endeavour, given that it's entirely a product of the unit system. In the system of Planck units gravity and coulombic force are identical!
Point is, gravity isn't weak,
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You can perform an experiment that will give you a rough idea of the difference between the relative strength of gravity and electricity. Just rub a piece of plastic or glass with a piece of fur. Then bring that rod of plastic or glass near some styrofoam peanuts or little paper bits and see what happens. Watch the electric force of a tiny glass rod easily overcome the gravity of the whole planet!
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Funny example of an article to reply to... considering there is a massive amount of plasma physics research related to accretion disks around black holes. This is actually one of those cases where electric and magnetic properties can partially dominate over gravity, yet Electric Universe people still seem to get it so messed up.
The jets are not escaping from the event horizon, but is a fraction of the plasma being ejected while the rest falls in. There are quite a few models and computer simulations tha
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"...At least you didn't, at least explicitly, state that astronomers and physicists ignore electrical properties..."
It is true that gravity predominates whenever things are nicely electrically neutral, as they are here on earth and in many parts of the solar system. However, the universe as a whole is a highly electrically charged place, where charges are often widely separated. The sun itself for example is a raging ball of plasma. If you know anything about plasmas, you would know about the 3 modes of cu
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Things that have "never been observed in the real world" by this sort of standard include nearly everything we know. Here's how science, more specifically physics, works. A regularity of nature is observed, for example, letting go of rocks and observing them to fall. Second, a theory is proposed to expl
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Wow, that was a long and detailed reply. You mentioned Occam's razor. The present cosmological theories, which depend mostly on gravity, are very complicated and require objects or entities that do not exist, at least here on earth. If the electrical forces is included in interpreting the astronomical data and observations, the mathematical equations can be even more complex, but they don't require things that have never been observed to exist here on earth.
One of the things you mention in your reply is the
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Your argument fails for numerous other reasons, most of them revealing an appalling lack of understanding of elementary thermodynamics and mathematics. For example, you wish to asser
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I am surprised and honored in a highly pleasant way that you are taking time out from what must be a very busy professor's life to write such a lengthy reply. It is a small world indeed. I have a daughter at Duke University who happens to be, as most Duke folks an ardent fan of the Blue Devils. She already has a Masters degree from the Duke Divinity School and is almost finished with her doctoral dissertation, which will give a Th.D.
I am an electrical engineer, now retired. I worked for and with physicists
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The fact that neutrinos can be produced by ELECTRICAL means in accelerators means that they can also be produced by electrical fields and currents on the sun. They do not have to be produced by thermonuclear fusion. Therefore, the presence of neutrinos from the sun cannot be taken as exclusive evidence for fusion taking place in the center thereof.
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I am not a physicist and so I don't really know the intricate details of how neutrinos are produced in accelerators. All I do know is that all accelerators are run by electricity. Therefore, a sun powered by electricity rather than nuclear fusion can and does produce neutrinos. My point is that the electrical interaction can and does produce neutrinos.
Gravity per se, cannot not produce any energy. In hydroelectricity, for example the energy to lift the water into the atmosphere comes from the sun. External
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Your assessment is correct, but you forgot (or left out) one key fact:
a black hole's gravity is so strong that it warps space itself.
As a black hole drags material into itself, the gravity is so great that it breaks the very bonds of matter, and anything beyond the event horizon ends up composed of pure neutrinos or planck units or strings (or whatever..), and if its strong enough to break matter down into that form, on that scale, there's no telling what could happen as a result.
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The one thing I don't really see reflected in your treatment of the physics is time.
If I fell into a black hole, I'd accelerate towards the center. By the time that I got there, would anything still be left there? I'd never encounter matter before the center, since it would be falling in ahead of me and so would any force carriers it emits in my direction. From my own frame of reference little time would have passed by the time I reached the center. However, from the external universe's perspective quit
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And if it IS a solid physical body that is spinning, then one could suggest that there is slightly more gravity at the 'poles' and less at the 'equator' because of the spin (and the related centrifugal force) right? But we all learned that gravity should be equal at a black hole everywhere, otherwise it would collapse.
So how does that work out?
Or am I making a some sort of an obvious mistake here. (that is well possible)
--
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The same equations that led to the idea of a black hole have spinning solutions. The non-spinning solutions are a little easier and were found first, but the spinning case was quickly found afterward
Geek alert: Only if by "quickly" you mean "nearly fifty years later, due to a fluke, and during which time the field of General Relativity was almost abandoned".
Schwarzchild [wikipedia.org] published his solution for non-rotating spherical masses (containing the singularity which implied black holes, which incidentally Einstein considered unphysical) in 1916, in the middle of World War I, right after Einstein released GR 1.0.
Roy Kerr [wikipedia.org] didn't find the solution for rotating black holes until 1963, the year that Kennedy was as
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I postulate this is where sock mates and end wrenches from sets, wind up in the end.
Intangibles too , like morality of politicians, virginity of the inebriated and value of copyright disappear down these mystical toilets.
If you remove the mysticism from something and define it prematurely, you end it's potential value which may be discovered later and put to use as beneficial. Beware of those declaring scientific fact and question their motives, lest we end up with a flat earth that the Sun revolves around.
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What?!?!? You found my missing socks? That Black Hole owes me a Shit TON of cotton!
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There are also potentially practical applications given far greater technology than we have now. Imagine using black holes to generate energy, or as massive particle accelerator laboratories!
A black hole could also be used as a gravitational slingshot for interstellar voyages. Come in as close to the event horizon as you dare, and burn your fuel deep in the gravity well. This could easily shave a few millenniums off the duration of a voyage across the galaxy.
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I can't imagine wanting to get close enough to a black hole to utilize it for production, can you imagine it's more likely potential for disposal? Pollution, politicians, lawyers and holiday fruitcake are the most useful fodder. The ultimate document shredder as well.
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GP says harnessing black holes are around the final corner, not the next corner.
Niche Market (Score:2)
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looked yesterday (Score:3)
Any one see that figure?
I tried to use my laser rangefinder to measure it but it kept coming back infinity.
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The Schwarzschild radius of a black hole (or anything, really) is a function of the mass.
No, its charge and rotation most definitely are not.
approximately 3 billion solar masses (Score:4, Insightful)
concentrated in a region at the galactic core that is only about the size of the Solar System.
http://csep10.phys.utk.edu/astr162/lect/active/smblack.html [utk.edu]
It's so dense that most of your comment (Score:5, Funny)
was compressed into the subject
It's so dense that most of my comment (Score:2)
never made it past the event horizon.
Well, yeah (Score:2)
"Some of the material from this orbiting 'accretion disk' is also falling into the black hole, like water swirling down a drain."
Isn't that pretty much the reason it's called an "accretion disk"?
Re:I've never understood this contradiction (Score:5, Informative)
Vacuum fluctuations cause a particle-antiparticle pair to appear close to the event horizon of a black hole. One of the pair falls into the black hole whilst the other escapes. In order to preserve total energy, the particle that fell into the black hole must have had a negative energy (with respect to an observer far away from the black hole). By this process, the black hole loses mass, and, to an outside observer, it would appear that the black hole has just emitted a particle.
http://en.wikipedia.org/wiki/Hawking_radiation [wikipedia.org]
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Has anybody ever seen or measured a particle with “negative energy”? What is negative energy? It sounds to me like something that has never been observed, such as dark energy, dark matter, black holes and other purely mathematical constructs that have been invented in the equations of mathematical physicists, but never have been demonstrated to exist in the real world.
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That's the one thing I hate about theoretical science... think it up, and change it to fit a blank "unknown" until it's actually known what is there.
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Actually yes, all the time. In many cases, the relevant quantity is change in energy and not absolute value of energy. Hence, where you set the zero point is arbitrary and usually chosen some place to just simplify the math (instead of carrying some junk around that you can demonstrate will disappear when you calculate a measurable value). For example, it is pretty common to treat the zero point at infinity, and so any bound system will be consider negative energy. For an example, an electron being capt
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All phenomena associated with black holes such as Hawking radiation, can be explained much more elegantly with known electrical and magnetic principles that work quite well here on earth, not only in the depths of space.
I wish I could get some of that mathematical negative energy to turn my electric meter backwards, so my electric bill would be much lower.
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"That is actually really easy... just hook a generator up to your electrical service"
Except that the generator has to have a source of energy which is positive. I don't really know anything about negative energy, so where does it exist here on earth in the real world?
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In order to preserve total energy, the particle that fell into the black hole must have had a negative energy
That's the thing I never understood about Hawking radiation. Why must it always be the negative particle that falls into the black hole? I don't see how that preserves any energy, or why it even matters that it does. It would make more sense and would seem to preserve total energy better if the particle that enters is random.
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The streams and radiations comes from compressing matter BEFORE it crosses event horizon - before that, light (or slower particles) can escape.
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Both the replies are correct, but the AC is more relevant. We can't measure the Hawking radiation from particle-antiparticle production and it most certainly doesn't come out in a jet. The article is behind a paywall, but I think they concluded that the black hole itself was spinning based on the gravitational effect on the jet. The distortion of spacetime is different for a spinning black hole and a stationary one.
I have never really understood.. (Score:2)
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But a black hole is a barrier where stuff can go in, but nothing can come out.
Stuff comes out... that's what the jets are.
It's broken down into very basic radiation. Not sure why this seems to always be overlooked by people...
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The jets originate near the event horizon, not inside. The matter near the horizon is very hot moving quickly, leading to all kinds of magnetic interactions/etc. However, I don't think anybody fully understands how jets work - hence the desire to get better imaging of the area around the event horizon.
Once inside the black hole nothing escapes, except in the form of hawking radiation. Hawking radiation is VERY weak in general, and shouldn't have any significant effect on things like jets that operate on a
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... Hawking radiation is VERY weak in general, and shouldn't have any significant effect on things like jets that operate on a galactic scale...
Just how weak? The amount of energy radiation by the M-87 black hole is just 10^-46 watts. How small is this? It would take 25 billion times the age of the Universe for the M-87 black hole to emit the energy of one photon of visible light (the smallest quantity of energy a human could directly detect). Hawking radiation drops with the inverse square of the mass, and so become immeasurable for all astronomical black holes.
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Our universe is 13.5 billion years old because 13.5 billion years ago a black hole formed inside of the parent universe that contains it. Crap could still be falling into it from the parent and that may be what causes the readings we attribute to such things as dark matter and expansion.
Not so fast. Inside the event horizon, distance from the the center becomes time-like, so you cannot move further from the center, while time becomes space-like. Seen from the inside, the event horizon is a time-point, not a position. So all mass materializes at the same time (it might move a bit further back in time as the black hole becomes larger), which kind of looks like a big bang.
You spin me right round baby right round... (Score:1)
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electrons have spin but they have no size, they are point entities. if they had any spacial extent at all they would have to be spinning faster than lightspeed to yield their obverved spin properties. how does that make you feel? how does a point entity spin?
Spinning heart of darkness huh? (Score:2)