A Black Hole's Spinning Heart of Darkness

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."

Comments

Fascinating

[dreamchaser]

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

[tysonedwards]

Doesn't this point more to a possibility that a black hole is a solid physical body which manifests it's own physical rotation rather than some of the former mysticism explanations that have persisted to date?

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.

Re:Fascinating

[fuzzyfuzzyfungus]

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...

Re:Fascinating

[ShanghaiBill]

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.

Re:Fascinating

[Anonymous Coward]

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

Re:Fascinating

[Cruciform]

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.

Re:Fascinating

[Baloroth]

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.

Re:Fascinating

[Anonymous Coward]

Noone will ever get to see it, the galactic center has exploded in a chain reaction of super nova's. I thought evryone knew this?

Re:Fascinating

[SGDarkKnight]

Ha! "HER medium" must of been one of those certified psychics!

Re:Fascinating

[Anonymous Coward]

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

[Anonymous Coward]

Even if you live that long, you won't see it; there's a reason they named it a black hole. As for using one for any purpose whatsoever, you'd have to be able to either create or travel to one. And since the odds of mankind surviving long enough to develop, let alone implement the technology necessary to carry this out are currently somewhere just shy of zero chances in a google, I'd say your disappointment is overblown.

Re:Fascinating

[Razgorov Prikazka]

I was thinking in the same lines I guess.
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)

--

Re:Fascinating

[Baloroth]

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.

Re:Fascinating

[Anonymous Coward]

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.

If you could find a naked black hole, maybe. Most have a pretty dense accretion disk. And tides. OMG, the tidal forces are insane. Anyway, we have no idea how to make a ship that can survive the speeds you are talking about. Interstellar matter becomes like cosmic radiation.

Re:Fascinating

[Anonymous Coward]

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.

Re:Fascinating

[tragedy]

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.

Re:Fascinating

[brisk0]

[...] 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, nucleons are just kind of light.

Re:Fascinating

[Anonymous Coward]

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 that can demonstrate jets working as such, using both general relativity and plasma physics. It is not like they are mutually exclusive, and in fact work together quite well. They however do not require ,massive external current sources.

At least you didn't, at least explicitly, state that astronomers and physicists ignore electrical properties... if I had a good drink for every time I've heard someone claim that, and a good cupcake for every talk I've attended by actual scientist directly discussing what arm-chair scientists say they never discuss, I would have died of cirrhosis and diabetes years ago.*

Since the force of gravity is the weakest of all known forces, the observations are more likely to be due to the electrical force, which is 39 orders of magnitude greater than gravity.

Yes, it is that many times stronger if you have a universe with only two charged particles. Once you start talking about three or more particles, some of which oppositely charge, this will no longer be the case. Opposite charges can shield effects. If you have a positive and a negative close together, their dipole electric field will eventually drop with the distance cubed, while their gravity drops with distance squared. If you combine more opposite charges together, the electric field drops off even faster. It should be pretty obvious at some distance, gravity will be stronger. The issue of which is actually dominating a system depends on the details of the system, and can differ from case to case. Anyway, there is plenty of active research that takes both effects into account.

* (Disclaimer, 95% of what I've published has been non-astrophysical plasma physics... )

Re:Fascinating

[Anonymous Coward]

Look up topics like the Ergosphere. A spinning black hole is no longer completely spherically symmetric any more and there are regions that are not spherical. The event horizon is still spherical though, as regardless of if the black hole is spinning or not. The event horizon is not some physical object that would be subject to centripetal forces, by a geometric boundary between the region where light (and matter with enough effort) could still potential escape if pointed in the right direction. Considering light is already going as fast as it can, the effects of spinning aren't going to boost it such it can now leave when it couldn't without spinning. There are situations where spinning might make it easier to push/pull matter (e.g. a spacecraft) out of the black hole, but it doesn't change the point where it becomes impossible.

In kind of response to the grandparent of this post*... this doesn't really add any evidence that black holes are physical as opposed to an effect of general relativity. 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 and is just as rigorous, although more interesting (and more realistic, as it was never expected a black hole would have perfectly zero angular momentum).

*Slashdot comment limits makes it difficult to respond to science articles I have a background in. I probably average far fewer posts than others but then have bursts on articles like this. I need to conserve posts based on what I expect to need more responses/explanation... but probably for the better at the moment, having just got back from even with a lot of drinking...

Re:Fascinating

[grantspassalan]

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 rules we use here on earth every day.

Re:Fascinating

[grantspassalan]

At least some of the beliefs of the electric universe theory don't require fictitious, purely mathematical constructs such as black holes, black energy, dark matter and other science fiction that only works in the computer and has never been discovered in the real world. 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.

Re:Fascinating

[grantspassalan]

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!

Re:Fascinating

[Rich0]

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 quite a bit of time would pass. So, could the entire black hole dissipate via Hawking radiation before I get there?

Of course, who knows how physics works inside a black hole in the first place. I just think that when you factor in time the picture of the inside of a black hole likely gets quite a bit more complicated.

Re:Fascinating

[grantspassalan]

"...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 current flow through a medium such as interplanetary and intergalactic space. In most places the current flow density is small, so we do not directly observe these currents. They can however constitute enormous current flow. When the current density gets a little higher, the plasma switches to glow mode which we can and do observe. The polar aurora are examples of plasmas operating in glow mode because of the electric current emitted by the sun. When the current density goes still higher, the plasma switches into arc mode, such as enlightening here on earth and intense electrical arcing on the sun. All moving charged particles produce a magnetic field which tends to focus the moving stream of particles into filaments. These filaments can often be light-years long. Their current density in many places is high enough to operate in glow mode, so we can see them with our telescopes.

  What astronomers call “Jets” emanating from so-called black holes can be explained by the well known laws of electricity and magnetism, without resorting to purely mathematical constructs such as black holes. What prevents a black hole from collapsing into an infinitely dense so-called “singularity”? Black holes, dark matter, and dark energy has never been observed in the real world, because they are mathematical fictions that only exist in the equations and computers of theoretical astrophysicists.

Re:Fascinating

[Anonymous Coward]

If you know anything about plasmas, you would know about the 3 modes of current flow through a medium such as interplanetary and intergalactic space. In most places the current flow density is small, so we do not directly observe these currents. They can however constitute enormous current flow. When the current density gets a little higher, the plasma switches to glow mode which we can and do observe. The polar aurora are examples of plasmas operating in glow mode because of the electric current emitted by the sun. When the current density goes still higher, the plasma switches into arc mode, such as enlightening here on earth and intense electrical arcing on the sun.

Actually, as an experimental plasma physicist, no, I've not come across reference material or phenomenon in the lab that divide current flow into those categories.The amount of glow typically has more to do with the temperature of the plasma. It helps that higher temperature usually has lower resistance, but there are plasmas with current and no glow, whether because the glow is too faint, or the plasma is so ionized it is not emitting any atomic transitions and is too optically thin for blackbody observable blackbody radiation.

And just the presence of magnetic fields is not necessarily significant. This is why plasma physicists will frequent have to qualify or ask if talking about magnetized plasma or not, usually defined in terms of how large the gyroradius is in reference to the system size. And just being magnetized is not enough to lead to filamentation, as there are other possible outcomes depending on the particular case. There are definitely astrophysical plasma with structure is dominated by hydrodynamical flows and shocks as opposed to filaments. The particular parameters of different astrophysical systems, including electric and magnetic field strengths, are easily measured in a lot of cases with spectroscopy, so is not left just to assumption or guesses.

Re:Fascinating

[Anonymous Coward]

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 plenty of researchers trying to see if any modified models will do better in case that assumption is wrong. However, so far are evidence has strongly supported unmodified GR (the same as directly measured on earth and by our space craft), while alternative models have only partially described observed phenomenon.

Re:Fascinating

[Anonymous Coward]

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 analytically... just like computer models used to solve Maxwell's equations when you are not dealing with a perfect box/sphere/cylinder. Since the universe is not filled with stuff in the shape of one of the simple cases allowing analytic solutions to Maxwell's equations, MHD, etc., the electric universe theories would have to resort to computer models to check the equations produce the same results on scales larger than Earth (or a laboratory that is the same size or larger than the universe...).

In the electric universe model, electricity and gravity work together to explain observations

And welcome to astrophysics, which uses electromagnetism and gravity (along with plasma and particle physics) to explain observation... to explain a metric fuck ton of observation. To imply what you describe as different from mainstream astrophysics is either disingenuous, or completely ignorant of what astrophysics does.

Re:Fascinating

[Anonymous Coward]

These questions kind of touch on some questions typically posed and/or answer in intro general relativity classes (some provide much better conceptual answers than others...). An observer falling into a black hole will reach the singularity in a finite (and rather quick) time. You would still be able to see and feel your feet if you fell in feet first, assuming the black hole was large enough to not just tear you apart (at or even before the event horizon). The light signals are not able to increase their radius from the black hole, but neither is the rest of the observer in a sense. Since both are falling into the black hole, in some sense you can think of it as your head catching up with the light from whatever fell in just before you (although there are some easy mistakes to make taking that explanation too far).

That is the nice thing about GR though, is if you zoom in enough, any tiny, local patch of space will look like flat space, including at and beyond the event horizon. Of course, if you had a small enough black hole, something the size of a human would not be "zooming in enough," but the tidal forces involved in that would be well beyond material strengths, regardless of if you were at the event horizon or not.

Re:Fascinating

[arkane1234]

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.

Re:Fascinating

[flyneye]

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.

Re:Fascinating

[flyneye]

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.

Re:Fascinating

[rgbatduke]

Black holes, dark matter, and dark energy has never been observed in the real world, because they are mathematical fictions that only exist in the equations and computers of theoretical astrophysicists.

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 explain it, a theory that has been equations that supposedly predict the outcome from the time of Newton on. Third, computations are done that compare observations old and new to the predictions of the theory. Fourth -- and this is a key step -- the consistency of the theory, both with ongoing future observations and with all of the other theories that seem to consistently explain observational data is challenged and re-verified, ad infinitum. Steps three and four never really end, and sometimes require a revisitation of step two to either modify (small step) or throw out (big step) the theory altogether.

This process of guided, consistent inference is the basis for all human knowledge about the real world, scientific or not. When you say black holes have never been observed in the real world but plasma has, you are splitting a very subtle hair. Plasma has never been observed in the real world either -- light from plasma has, other phenomena connected to a hypothesized plasma have. On the basis of these indirect measurements of effect, we infer the existence of things we cannot directly "observe" (whatever that means, given the coarseness and finite range of our senses) as the cause, and believe in this cause to the extent that it is part of an extensive theory with substantial predictive power that consistently fits in to the overall interconnected web of such theories that constitute "physics", "chemistry", "biology", and all of the other sciences that provide well-founded knowledge about the real world.

Gravitation is precisely such a "theory", indeed, the first such theory, the theory that more or less began the Enlightenment. It is especially amusing that you recite black holes, dark matter, and dark energy as examples of "mathematical fictions" where (by assumption, since you seem to accept the existence of gravitation) gravity is real and observed; in all three cases they are either theories that result from the need to make gravitation consistent both with observation and with the equally well-accepted theory of electromagnetism, which among other things implies relativity theory and physically observed phenomena such as the bending of light by strong gravitational fields and the precession of the perihelion of Mercury, or from the need to rescue gravitation from complete oblivion as a failed theory, in the case of dark matter/dark energy. We can see -- direct observation, although sure it is with pretty extensive equipment that substantially enhances our senses -- many galaxies where the orbital velocity field of the galaxy is not consistent with the apparent mass of the galaxy. We can observe similar deviations from the expected behavior of gravitation in other cosmological measurements. A number of theories have been proposed, over many decades at this point, to account for these failures of observation to consistently agree with the existing theory of gravitation plus the other physics we strongly believe. One of many is that Newton's theory of gravitation is indeed wrong. Another is the existence of a "fifth force" that is "gravity like" in certain ways and that modifies the long range behavior of gravitation. Dark matter and dark energy are yet another, one that preserves the general theory of gravitation and accounts for the deviation via the presence of unseen mass in the case of dark matter, and what is more or less again a fifth force in the case of dark energy.

Do physicists "believe" in any

Re:Fascinating

[Anonymous Coward]

Black Holes the last frontier?
I doubt it.

Re:Fascinating

[Anonymous Coward]

Yeah! We don't even have the Concorde anymore, but harnessing black holes is *just* around the corner!

Re:Fascinating

[LordLimecat]

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).

Re:Fascinating

[redlemming]

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 Newton's Gravity to the concepts predicted by Einstein's Gravity.

That's not a bad approximation for many circumstances, of course.

There's a further complication in that quantum mechanics and theories of gravity are not well integrated. If the black hole really could be a point or anything really small, then it would seem that quantum mechanics would be applicable, but nobody knows exactly how that would work.

Attempts to integrate these two theories are incomplete at best, and tend to involve high level math.

Nothing in physics (or any science) depends upon mysticism.

Re:Fascinating

[Anonymous Coward]

Nonsense. No crimes are solved in an 8 hour shift. It only takes 40 minutes, plus commercial breaks.

Re:Fascinating

[Anonymous Coward]

stars are a lot closer then any blackholes. if u can get to a black hole then surely it would have passed many many stars on the way there... so unless u know of any close black holes, then it is far easier to go directly to the star. and u r not considering the required energy to slow down. Maybe this is an option for inter galactic travel, but no one is thinking about this now. Its just too too far and would take way to long to ever receive a signal back from such a probe.

Re:Fascinating

[qubezz]

No, only the puppeteers and Beowulf Shaeffer.

Re:Fascinating

[lennier]

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 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 didn't find the solution for rotating black holes until 1963, the year that Kennedy was assassinated and Doctor Who started broadcasting. And at the time, the mathematical mainstream opinion was that this solution was impossible. The Kerr metric led directly to the equating of quasars with black holes and was one of the key discoveries making the 1960s the "Golden Age of General Relativity", compared to the decades previously when GR had been a bit of a backwater. The "Golden Age" is also one of the reasons why Star Trek had warp drives, because space-time warping was suddenly a hot topic again in physics.

The Kerr-Newman solution for electrically charged rotating black holes, on the other hand, did come out "quickly" - only two years after Kerr's original breakthrough.

Disclaimer: I'm a complete physics layman who doesn't really grok GR at all, but I'm intrigued by the history of science and as a New Zealander I've paid some attention to Roy Kerr's story. And I'm also intrigued by the later Einstein and the fact that most of his work post 1915 was, then and now, considered as scientifically useless as his pre-1915 work was considered brilliant, even while he had become a cult pop icon.

Re:Fascinating

[tragedy]

Gravitational lensing has been observed. That should be all it takes for you to realize how massively wrong your statements are.

Re:Fascinating

[highphilosopher]

Wow! You totally stole this from Will Wheaton off TNG. Ok, not really, but have you considered writing?

Re:Fascinating

[highphilosopher]

What?!?!? You found my missing socks? That Black Hole owes me a Shit TON of cotton!

Re:Fascinating

[Mattcelt]

Any mathematics, sufficiently advanced, is indistinguishable from magic.

Re:Fascinating

[Anonymous Coward]

As an active research mathematician... no, they are clearly distinguishable: magic makes a lot more sense.

Re:Fascinating

[davewoods]

What part of "Last frontier" did you not understand?

GP says harnessing black holes are around the final corner, not the next corner.

Re:Fascinating

[grantspassalan]

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.

Re:Fascinating

[grantspassalan]

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 mathematical constructs. No one has ever at any time observed a black hole, nor has dark matter and energy been shown to exist in the real world. Our galaxy rotates for the same reason and by the same mechanism as a homo-polar electric motor. The force of gravity has very little to do with either one.

Re:Fascinating

[grantspassalan]

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 Sun. In ancient times, centuries ago people thought that the Sun was nothing more than a giant campfire. As mankind learn more about the energy interactions of chemistry, it quickly became apparent that no chemical reaction is energetic enough to produce the light and heat we get from the sun. So the energy source of the sun remained a mystery for a while. Then scientists discovered the immense energy of the atom. That seems to be a reasonable explanation of what makes our sun put out all this power. We have even created what could be called “miniature suns” on the earth, commonly called H-bombs. There are however a number of difficulties in reconciling the extreme variability of the power output of the sun in the electromagnetic spectrum outside of the light and heat we depend on for our lives here on earth. An internal heat source, such as a fusion reaction deep in the interior of the Sun is not likely to allow for the extreme variability of output in ultraviolet and x-ray's over the known 11 year solar cycle. You also mentioned neutrinos. The number of neutrinos that the sun produces is far lower than what you would expect, if fusion were taking place deep in its interior. To make that data fit the fusion model, a mechanism called neutrino oscillation was introduced. So far, since neutrinos are so elusive, this has not been experimentally confirmed.

There are a number of other difficulties for the fusion model, such as sunspots and the fact that the corona is so much hotter than the solar “surface”, that is the photosphere. If the sun were truly heated from its interior, sunspots should be lighter not darker. Sunspots are nothing more than holes in the solar atmosphere exposing the cooler layers underneath. Well understood thermodynamics require that heat always flows from the hotter to the cooler regions. That is reversed in the case of the sun. An externally powered Sun allows for rapid fluctuations in total energy output of the sun, yet an electrical negative feedback mechanism ensures that the vital heat and light we depend on is remarkably constant throughout the entire solar cycle.

As for the supposedly age of the earth or even the universe, all those estimates depend on certain assumptions. One of these assumptions is that the physical processes such as the speed of light and the inversely related Planck's constant have indeed been constant throughout all the ages of time. That may be a reasonable assumption, but it is an assumption taken on faith nevertheless. Despite of the great increase of knowledge in the last few centuries, the nature of time itself remains a deep mystery. Scientists have learned to measure time more accurately than any other physical quantity, yet I have never heard of an explanation what time actually is and why it moves in one direction only. Perhaps you, being a physicist have or have heard of an explanation of time.

Science and faith are not mutually contradictory or mutually exclusionary. The most important things in life can only be grasped by faith, because they are REVALED to you by a person you TRUST. If your spouse or significant other tells you of their love for you, there is no scientific way you can examine that. When you get onto an airplane, you assume, you trust that proper maintenance was done and the pilot knows how to operate a complicated machine that shoots you through the sky at 600 mph. Most of our life here on this Earth is based on faith and trust. In the end, it matters not so much WHAT you believe, but WHOM you believe and trust.

Re:Fascinating

[grantspassalan]

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.

Re:Fascinating

[Anonymous Coward]

No, rotation profiles do not require black holes, you are mixing up several things together. Evidence for black holes tends to be related to either study of accretion disks (in which case the effects of electromagnetism are heavily considered by those that study it), or related to observations like the stars around the center of the galaxy, where there are clear paths of stars orbiting or sling shotting around a massive body smaller than the size of the solar system.

Re:Fascinating

[Anonymous Coward]

You keep implying that models that include gravity are based on laws not tested on earth. This ignores that both general relativity and electromagnetism have been tested on Earth. If you want to argue that for some reason we can't assume that cosmological scale gravity is the same as gravity on Earth, then you should also be arguing that we can't assume cosmological scale electromagnetism is the same is on Earth. I said nothing about them being in conflict. Whether on purpose or not, you are suggesting a difference between in nature of the two theories that does not actually exist.

Re:Fascinating

[Anonymous Coward]

Except that we can measure the strength of magnetic and electric fields on the surface of the Sun via spectroscopy. These are conditions that we can and have reproduced in labs on Earth, with the spectroscopy aspect studied in great detail and precision. Those conditions do not bend light.

Additionally, Maxwell's equations do not allow for any bending of light effects by electric and magnetic fields in a vacuum. The effects of plasma on the index of refraction of light and bend is something else studied in rather strong detail due to its use in interferometer measurements in laboratory plasmas. The only place you can find electric and magnetic fields affecting light directly is in QED, which sets such high requirements on it, it would only be a observable for high energy gamma rays in the vicinity of a magnitar. Additionally, it is a scattering process, not a bending process.

Re:Fascinating

[Anonymous Coward]

To make that data fit the fusion model, a mechanism called neutrino oscillation was introduced. So far, since neutrinos are so elusive, this has not been experimentally confirmed.

Neutrino oscillations have been confirmed via several different experimental set ups. This includes observation of oscillations in solar neutrinos. While older detection method could only detect electron neutrinos, and hence only detected a third of the expected neutrinos (not "far lower" than what was expected), newer detectors based on different principles that can detect all three flavors detect three times as much, i.e. the amount expected. Additionally, oscillations have been measured for neutrinos produced in the atmosphere, nuclear reactors, and from particle accelerators, all confirming the oscillation for different energy scales.

Re:Fascinating

[rgbatduke]

As already noted, you are a decade or so behind on the neutrino oscillation problem. My office in the physics building at Duke (I'm a physicist, BTW) is across the hall from an entire group of neutrino specialists and you are categorically wrong. There is absolutely no doubt that the sun is powered by thermonuclear fusion.

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 assert that the sun is hottest on the outside and coolest on the inside so that sunspots are a glimpse into a cooler solar interior. Sadly, this is complete and rather obvious nonsense. The heat equation (look it up) states quite clearly that the distribution of temperatures in the absence of sources or sinks satisfies the laplace equation. One of the first things you learn in the study of partial differential equations is that the laplace equation always has both the maximum and the minimum temperature on the boundary surface of any enclosed volume (there is actually a lot more one can tell without even building an actual solution, but this is one of the theorems). There are also average theorems -- the temperature inside any spherical ball is the average of the temperatures on the surface of that ball. Therefore the temperature in the center of the sun cannot be less than the average temperature of the surface, and even with the simplest imaginable model of stellar formation, there would still be leftover heat on the interior from mere gravitational collapse (see e.g. brown dwarfs) and hence even without any fusion whatsoever the solar core would be hotter than the solar surface, even if the surface was being actively heated. So your argument there is again, simply incorrect.

Third, you seem to have some sort of strange bias against mechanisms or objects that cannot be observed "on the Earth". Sadly, I would have a very hard time writing out the number of 9's in the 99.99999.....9999% of the Universe that is not "the Earth", including pretty much all of the stars and galaxies and planets and ever so much more. In fact, we don't have a star at all on the Earth, not even the relatively nearby Sun, and not even in fusion thermonuclear bombs do we build a creditable approximation of the pressures, densities, and temperatures present in the Sun's core where fusion occurs. Do the arithmetic -- every second the Sun releases the total energy content of the complete conversion of 4.26 billion kilograms of mass -- call it one cubic kilometer of mass at Earth-like densities. Electromagnetic fields are easy to measure. We measure them precisely throughout the solar system. They are openly published. They are completely, totally inadequate to serve as a free energy source for the Sun. Electromagnetic forces are, in the end, what drives ordinary chemistry, and ordinary chemistry is orders of magnitude away from being able to account for the energy output, and this direct coulomb interaction energy is many orders of magnitude again stronger than the magnetic interaction energy on a per-atom basis.

You are incorrect that it is an "assumption" that the speed of light and constants of nature have been constant throughout all of the ages of time. We can look back in time 13.73 billion years by looking outward. We can see that the spectral lines of stars are unchanged over all of this time period. Since those spectral lines are determined by (among other things) the values of Planck's constant and the speed of light, both of which contribute to the fine structure constant, one has to propose an enormously convoluted and peculiar scaling that somehow causes them to vary, but vary in precisely the right way so that the Universe precisely and consistently appears to be as large and old as it is, but really it's not. That isn't impossible, but it is absurdly far from the best possible belief given the data. By far the simplest and best explanation of the data is that yeah, the

Re:Fascinating

[Anonymous Coward]

For example, you wish to assert that the sun is hottest on the outside and coolest on the inside so that sunspots are a glimpse into a cooler solar interior. Sadly, this is complete and rather obvious nonsense.

Be careful with your wording there. The corona is much hotter than the surface of the sun, and it is heated by electromagnetic means. The fact it is orders of magnitude less dense than the photosphere allow it to be heated to much higher temperatures, while at the same time it is optically thin, allowing the photosphere to radiate heat through the corona. Additionally, sun spots are slight depressions and are cooler, due to magnetic field activity there deflecting convection, in a sense removing some of the heat source and allowing radiative cooling relative to adjacent regions.

However, it is pretty clear that the sun spots are not windows into a cooler layer, as the depression depth is pretty small, especially compared to measured convection that would prevent any layering at those shallow depths. Additionally, there is a lot of work toward determining the internal structure of the sun via helioseismology, using the same principles that geologists use to map out internal structure of the Earth.

Anyway, the point is be careful to specify the photosphere is not hotter than the interior of the sun, if you just say outside, it can result in a "give an inch, they take a mile" situation because of the hotter corona. Annoyingly, armchair internet physicist discussion of the corona being hotter thing can quickly turn into a quagmire in my experience. Way too many claims of violating thermodynamics while missing fundamental concepts, and claiming therefore electromagnetism needs to be considered (kind of a "no shit" from astrophysicists having studied that for decades...), but some how morphing into "Our theory using electromagnetism is correct, while your theory that also uses electromagnetism is wrong because it doesn't consider electromagnetism."

Re:Fascinating

[grantspassalan]

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 to black holes, dark matter and dark energy. Unimaginably intense electrical fields and currents can and do produce all the electromagnetic radiation that are attributed to Black holes and other theoretical, mathematical constructs that are used to explain the strange observations that are being made by modern space probes and telescopes. ALL of the exotic particles that are assumed to be originating in the depths of space and at the center of our galaxy, have been and still are constantly being re-created by powerful accelerators using well-known laws of electricity.

Re:Fascinating

[grantspassalan]

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, even the most extreme gravity imaginable, does not and cannot produce electromagnetic effects. Gravity only works in places that are almost perfectly electrically neutral, such as where we live here on earth. Life as we know it cannot exist in environments of extreme energies. Gravity can only attract, whereas electrical charges can attract and repel. That fact alone opens up many more possible interactions and makes plasma physics very complicated but also very interesting.

Re:Fascinating

[grantspassalan]

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 travels is extremely big. The index of refraction in the region close to the sun, certainly can be different than in other parts of space. Only objects that have mass are affected by gravity. Do photons have mass? If they do, they would be infinitely massive, according to Einstein's mathematics when they travel at the speed they do, namely the speed of light. it is not gravity, but incredibly powerful electrical currents and magnetic fields that bend electromagnetic rays of light passing close to the sun.

Re:Fascinating

[grantspassalan]

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.

Re:Fascinating

[grantspassalan]

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 at Stanford University for over 30 years in high-energy physics. In all that time, quite a bit of esoteric physics rubbed off on me. I never got that deeply into the details of the standard model and its extensive zoo of subatomic particles. Science and technology have always fascinated and interested me from the time I was about 3 years old.

You did the deduce correctly that I am a Christian. I have looked into other faiths and have concluded that Christian beliefs are unique in at least two major aspects from all others. 1), All founders of other faiths are presently dead, but Jesus Christ alone claims to have risen from the dead and be alive today. 2), all other faiths, except the teachings of the Bible, especially the New Testament, have human beings reaching UPWARD towards whatever their God or gods or other object or person happened to be. The Christian faith is the ONLY one that has God in Jesus Christ reaching DOWN to mankind.

What other criteria besides faith is universal to all human beings? In the Bible we read in Hebrews 11:6 "But without faith it is impossible to please Him, for he who comes to God must believe that He is and that He is a rewarder of those who diligently seek Him." God did not specify knowledge, education, athletic prowess, physical beauty or any other human ability or quality. Everybody can believe and trust, even a little child. In Luke 18:16-17 we read: But Jesus called them and said, Allow the little children to come to Me, and forbid them not. For of such is the kingdom of God. Truly I say to you, Whoever shall not receive the kingdom of God as a little child shall in no way enter into it.

When his fellow disciples told Thomas, who was also a disciple, that Jesus Christ has risen from the dead, he would not believe unless he actually saw the risen Jesus. 8 days later, he did indeed see Jesus and this is what Jesus told him in: John 20:29 Jesus said to him, Thomas, because you have seen Me you have believed. Blessed are they who have not seen and have believed.

Even in science, where we pride ourselves in objective truth and experimental evidence, there is a large element of belief or faith. Just thumb through almost any scientific literature in any field of science, and you will find statements such as, “it is believed” or “most scientists believe” and similar statements. Scientists seek truth in our world, and all truth, whether scientific or philosophical is absolute, not relative. What differentiates science from religion or philosophy is that in many areas of science we can do experiments and observations to corroborate or refute our beliefs. Truth however, is truth that is always true whether we believe it or not. When my little 3-year-old grandson tells me that he loves his grandpa & grandma, I believe that he is telling the truth. He really does love us. There is no scientific experiment I or anyone else can do to test this. I would never have known this truth, if the little guy had not REVEALED it to me. In the same way, we little human children of God would never know anything about him, unless he chose to reveal things about himself to us.

Our human knowledge and intellect are very small. They are also at present incomplete and partial. The Apostle Paul writes very eloquently about this on his great chapter defining love in 1Corinthians 9–13. Science is constantly changing. New theories are being developed and discarded every day. What was once accepted as even “scientific fact” is now s

Re:Fascinating

[Anonymous Coward]

I doubled check some of the math on this one, and there is a long list of issues with the gravitational lensing being due to refraction:

Due to density of plasma lowering index of refraction, the plasma around the sun would have to increase in density the farther you get from the sun in order to bend the light in the direction we see it bend. If instead you used the index of refraction from plasma densities as currently measured, with the density increasing toward the sun, you get the light bending in the wrong way by an amount much smaller than the gravitational lensing. Trying quantitatively to get the same amount of bending measured of star light around the sun (for visible light), would require an unrealistically high density of plasma pretty quick since it needs to increase as you go away from the Sun, in conflict with direct measurements by satellites among other things.

The index of refraction version would also have the wrong time of flight compared to light being bent by gravity. The delay in signal has been measured to pretty high accuracy from space probes on the other side of the Sun, and agrees with the gravity estimate.

Additionally, those measurements to high accuracy have been consistent, which would mean if done by refracting through plasma and ignoring all other inconsistencies listed so far, that the plasma around the Sun could not be changing on the time scale of years, and would have to remain in the same position or density to some small fraction of a percent.

A big one: the index of refraction for plasma is dependent on the wavelength of light used. Gravitational lensing is not. The gravitational lensing around the Sun has been measured from radio to x-rays, all found with the same bending. Additionally, due to the wavelength dependence, the refraction of radio waves in the corona has been observed (unlike very small effect it would have on visible light), and is pretty easy to separate due to its wavelength dependence, and agrees with previous estimates of plasma densities around the sun.

Also, gravitational lensing has been observed due to Jupiter and Saturn, which have even less plasma around them than the sun. Gravitational effects on light can be seen right on Earth. (And although photons have no rest mass, the due have relativistic mass and momentum, you can derive the momentum even from Maxwell's equations... nonetheless, in GR that doesn't matter as it treats light as just going in a straight line through a space that is not flat.)

And again, all measurements of electric and magnetic fields near the Sun show values that are reproducible in the lab and not capable of bending light. The microscopic basis of index of refraction is due to light interacting with electrons, not their fields. The interaction between a photon and a field would be a photon-photon interact under QED, which is a higher order effect, therefore much weaker than an electron-photon interaction. This has been observed with gamma rays passing near the very strong electric field near nuclei. However, this process is very strongly dependent on wavelength, and only observable with gamma rays. Additionally, it is a scattering process, it would not bend light, only spread it out in all directions.

Even if we entertain the idea that the Sun has a current through it creating a magnetic field strong enough to do that with gamma rays (but not visible light), we would need an excessively large current. Not only would the simple amount of electrons needed to deliverer that current be enough to gravitationally perturb previous space probes (which also did not measure any such current anyways), the amount of electric power dissipated in the corona would be 10 orders of magnitude higher than the actual power output of the sun (only looking at power dissipated right near the sun, it would be much higher if adding up stuff further away). Additionally, such magnetic fields would still be quite strong near earth, strong enough to pull apart satellites and pull iron off t

Re:Fascinating

[Anonymous Coward]

Neutrinos produced in accelerators are, for example, done by the decay of muons and pions which is a weak force process, not an electromagnetic process. The muons are created by the collision of high speed particles, which don't care how they got their high speed, whether from gravity or electromagnetism. For the sun to create neutrinos via this process, it would require some process much stronger than fusion to create the muons. Additionally, the amount of energy would be much higher to create the muons that eventually produce the neutrinos. The sun would have to be producing at least tens to hundreds of times as much power as it currently does to produce the number of neutrinos we see, in some ideal, non-thermal case. The solar neutrino energy spectrum is really different from that produced by a muon beam, and if this were happening any where near the surface of the sun, there would be all sorts of other, very distinctive emissions from such processes that we do not see.

Also, sort of in reply to another post too, to say the neutrinos are produced by electromagnetism is kind of convoluted. In the same sense gravity can create electromagnetism by just pulling pulling something down and spinning a generator like hydroelectricity, or even with some really fun but simple toys like Kelvin's Thunderstorm which uses just falling water to generate high voltages.

Re:Fascinating

[grantspassalan]

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.

Re:Fascinating

[grantspassalan]

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 energy must be supplied for your toy example also. Gravity does not GENERATE any energy in any way shape or form. It can be instrumental however in CONVERSION of energy from one form into another. When you wind up a clock spring, that spring does not produce any energy, but is merely an energy storage device.

CYGNUS X-1 DARK AND MYSTERIOUS !!

[Anonymous Coward]

That one ??

Niche Market

[Beardydog]

I can't actually think of any other things that are invisible, only partly understood, and evoke a sense of mystery. Do ghosts count? I don't think ghosts should count.

Re:Niche Market

[wonkey_monkey]

What about "the popularity of Justin Bieber"?

Re:Niche Market

[dead_user]

Never underestimate the spending power of preteen girls.

Re:Niche Market

[Anonymous Coward]

love? emotion? human stupidity?

Re:Niche Market

[Anonymous Coward]

What about "the popularity of Justin Bieber"?

That's a damned good question, and it leads to another: how many Justin Biebers could you take in a fight?

Re:Niche Market

[Anonymous Coward]

I can't actually think of any other things that are invisible, only partly understood, and evoke a sense of mystery

How about anything smaller than visible light? (Although your mileage might vary on the third quality.) There are numerous other theories and properties of the world around us that are directly visible, but well studied by looking at their impact on things we can see. Black holes might not be as well studied as many of those, but the point is not to think of them as any more invisible than any other theory that requires indirect observation.

looked yesterday

[WGFCrafty]

I read an article about this same black hole yesterday. It talked about measuring the diameter of the black hole, yet even when I tracked down the press release I couldn't find a measurement

Any one see that figure?


I tried to use my laser rangefinder to measure it but it kept coming back infinity.

Re:looked yesterday

[Anonymous Coward]

I read an article about this same black hole yesterday. It talked about measuring the diameter of the black hole, yet even when I tracked down the press release I couldn't find a measurement

Any one see that figure?

I tried to use my laser rangefinder to measure it but it kept coming back infinity.

The Schwarzschild radius of a black hole (or anything, really) is a function of the mass.

Re:looked yesterday

[K. S. Kyosuke]

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.

Re:looked yesterday

[Anonymous Coward]

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.

I was saying all matter has a Schwarzschild radius.

Re:looked yesterday

[Anonymous Coward]

The mass inside a non-rotating black hole is proportional to the surface area of its event horizon. Which is weird... its as if 3d matter gets squashed into a 2d surface.

approximately 3 billion solar masses

[MRe_nl]

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

Well, yeah

[93 Escort Wagon]

"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"?

"jets of particles to shoot out of the hole"

[Anonymous Coward]

Strictly speaking, the particle streams don't come from the hole itself (nothing can), they are from the event horizon around the hole.

I've never understood this contradiction

[Anonymous Coward]

If nothing can escape the gravity, then how is anything escaping the gravity? Does not follow logic.

Re:I've never understood this contradiction

[MRe_nl]

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

Re:I've never understood this contradiction

[Anonymous Coward]

The streams and radiations comes from compressing matter BEFORE it crosses event horizon - before that, light (or slower particles) can escape.

Re:I've never understood this contradiction

[fa2k]

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.

Re:I've never understood this contradiction

[grantspassalan]

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.

Re:I've never understood this contradiction

[amRadioHed]

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.

Re:I've never understood this contradiction

[arkane1234]

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.

Re:I've never understood this contradiction

[Anonymous Coward]

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 captured by an ion goes from zero energy far away from the ion to releasing energy when captured, hence the electron is at negative energy. It is a matter of bookkeeping, not some deep statement of how the world works in the end.

Additionally, another example that is also relevant is how some solutions to an equation that gave negative energy ultimately lead to the prediction of antimatter. In the end that negative sign didn't mean much, as they still act just like regular matter, and it only was relevant in interactions between the two.

Both of those cases are relevant to Hawking radiation, and both of those have observational backing.

Re:I've never understood this contradiction

[Anonymous Coward]

It is not like one particle is negative and the other is positive, and it is random which one goes in. It is a whole process, where one ends up with positive energy because it is the one going outward. The reverse is not emitting a particle that has negative energy, but would be a positive energy particle coming in from the outside (i.e. something falling in). There is probably some analogy that you can make about a diode, where you can talk about the holes moving around, but have to remember it is actually the electrons moving.

Re:I've never understood this contradiction

[grantspassalan]

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.

Re:I've never understood this contradiction

[Anonymous Coward]

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.

Elegance is probably in the eye of the beholder, because I've sat through presentations of accretion disk models that were pretty elegant with basic non-ideal MHD and GR. And I'm not sure what the point of explaining Hawking radiation with any alternative model is, because that one of the aspects not observable (although some experiments will soon be testing the a more generalized version of Hawking radiation within a laboratory).

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.

That is actually really easy... just hook a generator up to your electrical service. If you are going to try to argue that such simplified versions of negative energy as introduced in the previous post are just mathematical constructs, then you would be burying your head in a really deep hole. Those aren't just things demonstrated in labs on Earth, those are concepts demonstrable in front of high school physics classes.

Re:I've never understood this contradiction

[grantspassalan]

"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?

Re:I've never understood this contradiction

[Anonymous Coward]

Several examples have already been given. It seems pointless to just repeat them or repeat what is already written about an high school or freshman intro to physics textbook. Check the sections on gravitational potential energy or even sections on the importance on differentiating between electrical potential and potential differences, how the latter is more relevant while the zero point is a matter of convention or convenience.

Re:I've never understood this contradiction

[badkarmadayaccount]

Kazimir effect.

I have never really understood..

[Brad1138]

Why there is such "mystery" around black holes. It seems that a black hole isn't that different from a star or white dwarf or neutron star (etc), it has just attained such a massive field of gravity that light can't escape. Theories like they are the opening to a worm hole is just ridiculous. If you got to close to one, your fate would be very similar to getting to close to a neutron star.

Re:I have never really understood..

[RedDeadThumb]

There is no mystery of what happens if you get close to one. The mystery comes from not knowing what goes on inside of one. You know that a neutron star is just a bunch of neutrons clumped together. But a black hole is a barrier where stuff can go in, but nothing can come out. We don't know what happens to gravity or space or matter that is inside of one. So we really have no clue what is going on in there, it is all just guesses. My own theory is that inside each one is another universe. The UNIVERSE is an infinite tree of holes with holes inside them. 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. For example if it could be shown that the expansion rate varies that could be explained by the availability of matter in the parent universe to be sucked into this one.

Re:I have never really understood..

[Anonymous Coward]

What I'm annoyed by is how much speculation there is about the goings on inside the event horizon.

The very theories that predict black holes also state that a black hole cannot be observed to form. To put it another way, for anybody outside a black hole, a black hole cannot exist. At best, it can be a shorthand way of talking about an asymptotic condition, but no matter or radiation can ever (seem to) sink into a black hole, and there are no direct or indirect effects of a black hole to its surroundings.

More to the point, no statement about the innards of a black hole can be tested even in principle. What follows is that those statements are not in the realm of science.

A physicist once told me that you surely can test the theories by falling into a black hole. By that reasoning, though, all religious statements about life after death are similarly "testable" and "scientific."

Re:I have never really understood..

[arkane1234]

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...

Re:I have never really understood..

[RedDeadThumb]

I thought the explanation was that the jets were from stuff that didn't manage to quite get in? See, it's a mystery.

Re:I have never really understood..

[Anonymous Coward]

The very theories that predict black holes also state that a black hole cannot be observed to form. To put it another way, for anybody outside a black hole, a black hole cannot exist. At best, it can be a shorthand way of talking about an asymptotic condition, but no matter or radiation can ever (seem to) sink into a black hole, and there are no direct or indirect effects of a black hole to its surroundings.

This is an incorrect interpretation or misreading of the effects of things falling into a black hole. Yes, when something falls into a black hole, an outside observer will essentially see it fall forever. You can think of as the object gets closer to the event horizon, light leaving takes longer and longer to get away from the black hole. The light that is emitted right as it crosses will essentially take forever. But this is far, far from saying the effects would be unobservable. As that light comes out, it would be further and further red shifted, and would become dimmer and dimmer. To a human observer, the object would disappear quickly as it red-shifts beyond visible light and becomes way too dim. Additionally, there are a whole bunch of other effects that happen in the immediate surrounding are observable, like bending of light and frame dragging effects.

Re:I have never really understood..

[Anonymous Coward]

Dark matter has been shown to be a large, hot halo of gas around every galaxy. It was just too dark to image until we built a better telescope.

Re:I have never really understood..

[Rich0]

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 galactic scale.

Re:I have never really understood..

[crunchygranola]

... 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.

Re:I have never really understood..

[sFurbo]

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.

Re:I have never really understood..

[sFurbo]

Non-baryonic gas, I presume, as big bang nucleosynthesis puts an upper limit on the amount of baryonic matter in the universe. Do you have a link detailing the discovery of these massive amounts of non-baryonic gas?

It's so dense that most of your comment

[kumanopuusan]

was compressed into the subject

You keep using that word....

[Anonymous Coward]

"Universe" means "all things taken as one." Whatever thing, or set of things, is inside the black hole would still be a subset of "all things." Therefore, it is not semantically possible for a black hole to contain "another universe." Whatever it contains, no matter how fantastic, still logically fits within the meaning of the word "universe."

Perhaps someday we will find "another metaverse?" And then we will have to make up the word "metametaverse" to mean the same damn thing that "universe" already means?

Sheesh. I am amazed that we can do science at all, given how badly we butcher our own language.

Re:You keep using that word....

[RedDeadThumb]

That is why I used "UNIVERSE" to represent the sum of all things and "universe" to represent what people commonly call the thing that started 13.5 billion years ago. It was the clearest way I could think of to represent the concepts I was trying to convey. Was my explanation not clear to you?

Re:troolkore

[Anonymous Coward]

Make that a spinning gif animation and you're topical once again.

It's so dense that most of my comment

[MRe_nl]

never made it past the event horizon.

So....

[Anonymous Coward]

It's a universal vacuum cleaner, so what? It does a better job than nasa does at taking the junk away.

Heart of Darkness == my Ex

[Anonymous Coward]

Spinning Heart of Darkness? But I thought my ex still lived here on Earth...

captcha : special

You spin me right round baby right round...

[Turminder Xuss]

What does it mean for a black hole to be spinning ? It has no electric charge, or if it does the space is so curved that photons carrying electromagnetic force are twisted back into the hole. How is gravity affected by angular momentum ? If there was a large imbalance in mass distribution around the axis of rotation then I could see that might create gravitational ripples, but it seems unlikely that a black hole would be lopsided. What even is it that can spin inside a black hole ? Eventually even the constituent hadrons are getting ripped apart by gravity What is left to spin when even chromodynamics can't exert a tangent to the gravitational centripetal force ? Perhaps past the event horizon, it's still normal matter spinning until it is ripped apart. Does a hungry black hole with no material falling into it still spin ? Also why am I asking so many questions ? Are you all supposed to be smart or something ?

Re:You spin me right round baby right round...

[rubycodez]

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?

Re:You spin me right round baby right round...

[Anonymous Coward]

In a sense, just like electromagnetic fields can carry angular momentum, gravitational fields can also carry angular momentum. A spinning black hole is just an extreme case of this. A less extreme, but tested version would be rotational frame dragging as seen by objects in orbit around things like the Earth.

the key of the bottomless pit?

[Anonymous Coward]

"And the fifth angel sounded, and I saw a star fall from heaven unto the earth: and to him was given the key of the bottomless pit." - Revelation 9:1

Spinning heart of darkness huh?

[TheGoodNamesWereGone]

I knew a woman in Kansas City just like that...