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Space Science

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."
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A Black Hole's Spinning Heart of Darkness

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  • Fascinating (Score:5, Interesting)

    by dreamchaser ( 49529 ) on Saturday September 29, 2012 @03:51PM (#41501035) Homepage Journal

    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)

      by tysonedwards ( 969693 ) on Saturday September 29, 2012 @04:13PM (#41501161)
      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.
      • 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...

        • 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).

          • 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

      • Re: (Score:2, Interesting)

        by 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 (Score:4, Interesting)

        by Cruciform ( 42896 ) on Saturday September 29, 2012 @04:48PM (#41501395) Homepage

        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...

      • Re:Fascinating (Score:5, Informative)

        by Baloroth ( 2370816 ) on Saturday September 29, 2012 @04:55PM (#41501445)

        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.

        • by 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.

        • by Rich0 ( 548339 )

          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

      • 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)

      • by flyneye ( 84093 )

        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.

    • 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.

    • by flyneye ( 84093 )

      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.

  • 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.
  • by WGFCrafty ( 1062506 ) on Saturday September 29, 2012 @03:55PM (#41501059)
    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.
  • "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"?

  • 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.
    • 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 UNIVERS
      • 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...

        • I thought the explanation was that the jets were from stuff that didn't manage to quite get in? See, it's a mystery.
        • by Rich0 ( 548339 )

          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

          • ... 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.

      • by sFurbo ( 1361249 )

        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.

  • 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 const
    • 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?

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

It's fabulous! We haven't seen anything like it in the last half an hour! -- Macy's