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Astronomers Discover 33 Pairs of Waltzing Black Holes 101

Posted by ScuttleMonkey
from the teach-them-to-foxtrot dept.
Astronomers from UC Berkeley have identified 33 pairs of waltzing black holes, closing the gap somewhat between the observed population of super-massive black hole pairs and what had been predicted by theory. "Astronomical observations have shown that 1) nearly every galaxy has a central super-massive black hole (with a mass of a million to a billion times the mass of the Sun), and 2) galaxies commonly collide and merge to form new, more massive galaxies. As a consequence of these two observations, a merger between two galaxies should bring two super-massive black holes to the new, more massive galaxy formed from the merger. The two black holes gradually in-spiral toward the center of this galaxy, engaging in a gravitational tug-of-war with the surrounding stars. The result is a black hole dance, choreographed by Newton himself. Such a dance is expected to occur in our own Milky Way Galaxy in about 3 billion years, when it collides with the Andromeda Galaxy."
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Astronomers Discover 33 Pairs of Waltzing Black Holes

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  • Waltzing? (Score:4, Funny)

    by CannonballHead (842625) on Monday January 04, 2010 @05:01PM (#30646092)

    Apparently, the definition "waltzing"/a waltz has been diminished to the extent that now it just refers to two objects moving together. Hum.

    I guess I'm just a cranky music theory lover though.

  • by Drummergeek0 (1513771) <<moc.ddb3> <ta> <ynot>> on Monday January 04, 2010 @05:01PM (#30646100)

    Who leads and who follows?

    • Re: (Score:2, Funny)

      by gstoddart (321705)

      Who leads and who follows?

      Well, it's governed by orbital mechanics and gravity ... so the bigger one technically 'leads', but the smaller one also exerts some influence. :-P

      Cheers

    • by OakDragon (885217)
      I'm assuming it's black tie only?
    • by MBGMorden (803437)

      They learn as they go. Sometimes one leads, sometimes it follows. They don't worry 'bout what they don't know. Galactic collisions is a dance you learn as you go.

      - JMM

  • OH NO! (Score:1, Funny)

    by madddddddddd (1710534)
    the Y3B bug already being dismissed as irrelevant
  • Newton? (Score:5, Insightful)

    by sznupi (719324) on Monday January 04, 2010 @05:07PM (#30646214) Homepage

    At those masses, the choreographer is most likely Einstein (nvm that dark matter might be not the underlying cause of some discrepancy between how we think gravity works and what we are observing at galactic scales; we might as well have a different choreographer yet)

    • Re: (Score:3, Informative)

      by bcrowell (177657)

      At those masses, the choreographer is most likely Einstein

      That's incorrect. The paper [arxiv.org] gives the orbital velocities as being ~100 km/s. If the black holes were close enough to one another for their orbits around their mutual center of mass to be significantly affected by relativity, their distance from one another would have to be comparable to the radii of their event horizons. But at a distance that's comparable to the radius of the event horizon, orbital velocities are a significant fraction of the spee

      • by sznupi (719324)

        Mercury orbits at half of those 100 km/s, and yet also at those orbital energies, curvature of space, you have to take into account relativistic effects to have any understanding of its orbit.

        As for as somebody else being the choreographer, I wasn't standing by the notion of it; just mentioning the possibility (and hey, for supermassive black holes acceleration resulting in orbital velocity of 100 km/s might fall under rather small BTW)

        • Re: (Score:3, Informative)

          by bcrowell (177657)

          Mercury orbits at half of those 100 km/s, and yet also at those orbital energies, curvature of space, you have to take into account relativistic effects to have any understanding of its orbit.

          No, that's incorrect. Newtonian physics is an excellent approximation to the orbit of Mercury. The famous relativistic effects on Mercury's orbit are tiny. To see them, you have to subtract out a whole bunch of other effects, some of them a hundred times bigger [wikipedia.org] than the relativistic one.

          and hey, for supermassive bla

          • by pnewhook (788591)

            GPS satellites need their internal clocks corrected to take into account relativistic effects based on the speed they are going. And they are only travelling at about 4km per second.

            So yeah, relativity does have an effect.

            • Re: (Score:2, Informative)

              by bcrowell (177657)

              GPS satellites need their internal clocks corrected to take into account relativistic effects based on the speed they are going. And they are only travelling at about 4km per second. So yeah, relativity does have an effect.

              Absolutely. But the relativistic effects are extremely small at those speeds. For instance, the relativistic time dilation aboard a GPS satellite is about 1 part in 10^10.

              • by pnewhook (788591)

                Absolutely. But the relativistic effects are extremely small at those speeds. For instance, the relativistic time dilation aboard a GPS satellite is about 1 part in 10^10.

                The relativistic effects on the GPS onboard clock due to its relative motion to the GPS receiver would result in the position calculation being shifted by 7 miles per day if it were not corrected for.

                • Re: (Score:2, Informative)

                  by bcrowell (177657)

                  The relativistic effects on the GPS onboard clock due to its relative motion to the GPS receiver would result in the position calculation being shifted by 7 miles per day if it were not corrected for.

                  Sure. The error in locating yourself on the earth's surface equals the time error multiplied by the speed of light. Since the speed of light is big, the technique is extremely sensitive to tiny time errors.

          • by arminw (717974)

            ....because supermassive black holes are observed at the *centers* of galaxies...
            Black holes, supermassive or otherwise have never been OBSERVED anywhere. They are mathematical constructs that are theorized to exist in the center of galaxies and maybe other places, but no one has ever seen one anywhere. They, as well as dark matter and energy are theorized to exist, because of the unexplained motion of heavenly bodies we CAN observe. Clearly something is causing stars and galaxies to move differently than o

          • by sznupi (719324)

            I still have the impression you think I was embracing alternative theories of gravity...oh well.

            But as for Mercury; well, the fact stands that even with all other factors, with tiny mass of the planet, we were seeing it in different orbit than it "should" be...with our capabilities from centuries ago. Never mind even that this effect would be only slightly stronger - it's there. Newton isn't the choreographer.

            • Re: (Score:2, Informative)

              by bcrowell (177657)

              I still have the impression you think I was embracing alternative theories of gravity...oh well.

              No, I pointed out that you'd misunderstood those alternative theories of gravity.

              But as for Mercury; well, the fact stands that even with all other factors, with tiny mass of the planet, we were seeing it in different orbit than it "should" be [...]

              Both in your original post [slashdot.org] and in this one, you seem to be displaying a misconception that the mass of the object is what matters. That's incorrect. What makes a

              • by sznupi (719324)

                No, I pointed out that you'd misunderstood those alternative theories of gravity.

                But I wasn't referring specifically to any of them, you did. I just left open the possibility that we might well still have some other choreographer in the future; my acceptance of general relativity notwithstanding.

                Anyway I'm perfectly aware what makes a black hole a black hole, their Schwarzschild radius, and so on. Which is irrelevant here anyway, since when discussing orbits mass is the only thing that matters. Those two objects could be two compact swarms of butterflies for all we know. ;p

                You are forge

                • by bcrowell (177657)

                  Anyway I'm perfectly aware what makes a black hole a black hole, their Schwarzschild radius, and so on. Which is irrelevant here anyway, since when discussing orbits mass is the only thing that matters.

                  No, that's incorrect. There are three quantities that could be relevant: the mass of the primary M, the mass of the satellite m, and the radius of the orbit r. Contrary to your previous statements, m is irrelevant for a highly asymmetric system like the sun and Mercury. What quantifies the strength of the gr

  • Wake me up when they've found some doing the Foxtrot or the Lindy Hop.

    • Re: (Score:3, Funny)

      by Red Flayer (890720)

      Wake me up when they've found some doing the Foxtrot or the Lindy Hop.

      Meh, that's no big deal. Wake me up when a bunch of black holes line up to dance.

      THEN you know we've got problems.

      Doo doo doo de do de do doo doo/
      Doo doo doo de do de do doo doo/
      Do the hustle!

  • "[...] a merger between two galaxies should bring two super-massive black holes to the new, more massive galaxy formed from the merger. The two black holes gradually in-spiral toward the center of this galaxy, engaging in a gravitational tug-of-war with the surrounding stars. The result is a black hole dance, choreographed by Newton himself. Such a dance is expected to occur in our own Milky Way Galaxy in about 3 billion years, when it collides with the Andromeda Galaxy."

    Don't worry - I'm sure Russia will have an ill-defined plan to divert this somehow. By then.

    (Sorry, couldn't resist.)

  • and this... (Score:4, Insightful)

    by owlnation (858981) on Monday January 04, 2010 @05:28PM (#30646530)
    ... is the only "Dancing with the Stars" I'd ever want to see.
  • Finally I can post this link and not be offtopic:

    http://www.youtube.com/watch?v=Cg1dMpu4v7M [youtube.com]

  • Einstein! (Score:3, Informative)

    by mbone (558574) on Monday January 04, 2010 @05:30PM (#30646552)

    choreographed by Newton himself.

    He might try, but the accurate calculation of black hole orbits requires the complete infrastructure of General Relativity, so Einstein is calling this tune.

  • Wow! (Score:4, Insightful)

    by gstoddart (321705) on Monday January 04, 2010 @05:33PM (#30646610) Homepage

    Wow, when I was in university, Black Holes were still a mostly theoretical idea and we had no real empirical evidence to support their existence.

    Now we've got 33 pairs of them entwined in death spirals, and we're pretty sure every galaxy has one.

    There's still a lot out there that we can't even conceive of ... I can't wait to see what the next 15-20 years brings us. I like the fact that the universe is vastly more complicated than we've ever really been able to guess at.

    Cheers

    • by pnewhook (788591)

      Wow, when I was in university, Black Holes were still a mostly theoretical idea and we had no real empirical evidence to support their existence.

      Was this a creationist university?

      • Re: (Score:3, Interesting)

        by gstoddart (321705)

        Was this a creationist university?

        *laugh* No, but it was pre-Hubble before they'd actually done the measurements to be fairly sure. There was strong theoretical evidence, but nothing they'd been able to hold up until '94 when they looked at M87. (Yes, there had been some evidence, but not yet conclusive.)

        Some of us went to university a long time ago, and the world has changed a lot since then.

        Like I said, I just continue to be amazed at the changes in my lifetime. You young kids think we've always known

    • by arminw (717974)

      ....Black Holes were still a mostly theoretical idea and we had no real empirical evidence to support their existence....
      They still are nothing but a mathematical construct, because nobody has ever observed one actually exists. They are inferred to exist, the same as dark matter and energy, because we observe stars and galaxies to move in ways that our incomplete knowledge can't explain.

      • by MBGMorden (803437)

        They've been observed as much as we can. If you're looking for a photograph, then you're not going to get one because by nature they're invisible. Seeing something isn't the only way to observe it though. In this case, it's simply NOT going to be the way you observe it. We know how gravity and mass works. We can easily observe stars in our galaxy for example swinging around an incredibly massive object at the center of the galaxy that is invisible.

        Invisible object, of that mass, at that size, IS a blac

        • by arminw (717974)

          ....swinging around an incredibly massive object at the center....
          That assumes (a belief, not knowledge) that gravity is the ONLY force that can govern the motion of objects such as stars. If there is electricity and/or magnetism involved in addition to gravity, then the assumption of a black hole is false. Just the fact that the electric force is 36 orders of magnitude greater than gravity, makes it quite probable that electric and magnetic fields would be a large factor in controlling the motion we observ

  • by photonic (584757) on Monday January 04, 2010 @05:40PM (#30646662)
    Great, the collision of these things is exactly the kind of event we need for detecting gravitational waves [wikipedia.org]. These kind of 'inspirals' emit very distinct pattern, which can be retrieved very efficiently from the noise with matched filter banks. The higher the mass, the lower the frequency of this 'chirped' signal, so it is probable that these colliding super-massive black-holes cannot be detected with the ground [caltech.edu]-based [virgo.infn.it] kilometer long observatories, which are measuring right now. This is probably more something for the space-based LISA [nasa.gov] mission, which can probe much lower frequencies since it has a base-line of millions of kilometers.
    • Re: (Score:3, Interesting)

      by bcrowell (177657)
      The same thing occurred to me. Here [arxiv.org] is what appears to be the paper describing the observations. It's remarkably silent on whether any of this has implications for gravitational wave astronomy or tests of general relativity. They basically seem to see it as purely a way of finding out about evolution of galaxies. I guess the fact that these pairs are reasonably frequent implies that you can make reasonable estimates, probably for the first time, of the rate at which black hole collisions should be expected.
      • by photonic (584757)
        They do give a merger rate per galaxy in the introduction of the article. If you combine that with a density of galaxies and the sensitivity of your detector, this should give you a rate of observable events. In the final paragraph they confirm my suspicion that this coalescing SMBHs are LISA's business and that their observations should give an upper limit to the detection rate. I don't know if this is good or bad news, that depends on the earlier predictions.
      • The orbit has decayed since the binary system was initially discovered, in precise agreement with the loss of energy due to gravitational waves predicted by Einstein's General Theory of Relativity. Hulse-Taylor binary [wikipedia.org]

        Cool, maybe in a couple billion years we'll finally know what happens when two waltzing blackhole kiss each other.

      • by pnewhook (788591)

        I wonder to what extent these black hole pairs can be used as laboratories for testing general relativity

        General relativity has been verified countless times, from the existence of black holes, to gravitational lensing, to even time dilation. General relativity effects are even needed to be compensated for in GPS clock calculations. Are there aspects of general relativity left to be tested?

        • by bcrowell (177657)

          General relativity has been verified countless times, from the existence of black holes, to gravitational lensing, to even time dilation. General relativity effects are even needed to be compensated for in GPS clock calculations. Are there aspects of general relativity left to be tested?

          Sure. Of course you have to distinguish between falsifying Newtonian mechanics and verifying general relativity. It only takes one observation to disprove a theory, but proving a theory correct is a whole different matter.

      • Very very long indeed. I understand the timescales in TFA are in million to billion years, so the frequencies photonic expects to detect would be conversely so low that this'll just be a constant at our timescale... I fear we'll not see a turn ;-)

        • by photonic (584757)
          If your detector is sensitive enough to observe lots of galaxies at the same time, you will be able to observe a few at the final stage of the inspiral. The system looses energy due to gravitational waves, thus the distance between the two objects will decrease and the rotation frequency will increase up to the point that they merge. It is this final stage that we want to detect, which the gravitational waves are sent with higher frequency and intensity.
  • Given that it's pretty common knowledge that a) galaxies have big black holes at their centers and b) that galaxies collide... is it really a discovery that black holes will orbit one another as their gravity catches hold of one another?

    I mean okay, it's cool to actually have proof of it but I am pretty sure I read about orbiting black holes a while back already. Not to take the icing off the cake here, I am probably more annoyed with the slashdot heading.
    • by mhajicek (1582795)
      There's a big difference between speculation and measurable data.
    • As with so much of science: if you went out there and didn't find it, that would be much bigger news, because it would cast doubt on your present theory.

      Confirmation is never as exciting as falsification, but it's good that science isn't all that exciting, or nothing would ever get done. The more confirmations you get, the further you can speculate, with the chance of getting something that can be falsified.

    • by MBGMorden (803437)

      That's the "common sense" idea, and it's simply not a good way to do things.

      To the average man a scientist trying to figure out why things fall, or measuring the speed at which they fall for example is wasting time. It's "common sense" that things just fall.

      However, many, many things over the centuries that were "common sense" have been proven wrong when subjected to scientific analysis (after all, it was once common sense that the Sun went around the Earth).

      Just dismissing every study as invaluable becaus

  • So if a single magnestar can produce a truly massive gamma ray blast just by displacing its crust by a couple of centimeters http://science.slashdot.org/story/09/12/27/1639207/Fifth-Anniversary-of-a-Cosmic-Onslaught [slashdot.org], what happens when two super-massive black holes finally merge?

    • by mhajicek (1582795)
      Good question, but I imagine not a whole lot would make it past the event horizon(s). There would be a bunch of energy released by the collision of the matter orbiting them though.
    • From our point of view, they take an infinite amount of time to actually merge, since time around them slows down to pretty much a standstill due to the huge gravitational time dilation. So I guess there's nothing to worry about. In fact, even the black holes themselves don't really exist yet, they will forever be "almost" black holes (though admittedly very, very close). Unless you fall into one. But that would take an infinite amount of time from an outside observer's point of view, too.
  • *golf clap* (Score:1, Troll)

    by drDugan (219551) *

    Okay, great. Exciting observations, but really, not that useful in the big scheme of where we are with physics today.

    How about you physicists show us Higgs? How do quantum mechanics and gravity mesh into a coherent theory? Explain the disagreement of 107 orders of magnitude (yes, you read that right: 107 zeros) between the upper bound upon the vacuum energy density (from data obtained from Voyager, less than 10**14 GeV/m3) and the zero-point energy of 10**121 GeV/m3 - calculated using quantum field theor

    • Re:*golf clap* (Score:5, Insightful)

      by Chris Burke (6130) on Monday January 04, 2010 @06:14PM (#30647180) Homepage

      But most of all, explain what causes the observed effects of hypothetical "dark matter" and "dark energy". My young children are smart enough to know that the dark matter story sounds like total and utter bull. The story goes like this: "We see something that looks like it causes things to move, but we don't know what it is, and we can't see it, or measure it, create it, or understand it at all. These unobservable matter blobs (and energy) may be 95% of everything we observe! We see something we can't explain, so we're calling it 'dark matter' and moving on with the old story that has worked for a while and still gets us grant funding." Why no one with a brain is calling out this story for its absurdity is astounding.

      Because people with brains -- or at least those with brains and a bit of particle physics knowledge -- know that the idea of a type of matter that has mass but does not interact electromagnetically and is thus extremely hard to detect is not that outlandish. We already know of one such particle, the neutrino. A more massive neutrino-like particle is a prime candidate for dark matter, and is predicted by theory outside of dark matter. And while it's still highly speculative, there are teams out there right now who believe they are on the trail of detecting this particle.

      In other words, they are doing exactly what you think they should be doing, and working on the problem. But surprisingly, doing actual useful work in this area requires more education than your children, or you for that matter, possess. Sorry!

      The most dangerous hubris in science is the refusal to accept that we're far more ignorant about our physical environment than most would like to admit.

      Stand in front of a mirror, look yourself directly in the eye, and say that fifty times.

      All the things you point out, like what dark matter actually is, are holes in physics knowledge that physicists readily admit too. At least to the extent that you accurately describe the holes, rather than your gut feeling about what sounds too weird to be true. So who is showing hubris again?

      • by steelfood (895457)

        I think the terminology used leads to confusion in the layman. "Dark matter" sounds like it's something real, like matter but that's undetectable. In actuality, it's just a placeholder for something unknonwn, like null in a database. It could be undiscovered matter, or it could be an undiscovered property of known matter. By giving it a term, most people end up with the impression that it's the former rather than both.

        • by Chris Burke (6130)

          I think the terminology used leads to confusion in the layman. "Dark matter" sounds like it's something real, like matter but that's undetectable. In actuality, it's just a placeholder for something unknonwn, like null in a database.

          Well it is in part just a placeholder for something unknown, not the name of some specific kind of matter. On the other hand, the reason it's called "dark matter" is because it is neither emitting nor reflecting enough light for us to see it directly. It is literally dark. An

    • You do understand that science is a process right? We're in the process of figuring all of that stuff out. How else would you even know to ask those particular questions?

      Your young children can be led to believe that Santa Claus and Easter Bunny exist, so I wouldn't exactly take their word for it on something like dark matter. The reason it's called 'dark matter' is because we don't know WTF it is. People are trying to figure that out. It's not as if they moved on, and decided to just not research
    • They shouldn't shows us a Higgs Boson particle as it would seal our fate as a "Type 13" civilization when our planet collapses into something the size of a pea due to experiments designed to find the mass of t6he Higg Boson Particle.

  • Funny how everybody is always talking about all those black holes in the universe while, in fact, none currently exist. Sure, there are objects that are very, very close to becoming a black hole, and for all practical intents and purposes they can be pretty much considered as such, but in our reference frame it will still take an infinite amount of time before that last bit of matter falling in makes it an actual black hole, with event horizon and all. That's because the intense field of gravity slows down
  • The classical google portal has an interesting Newton animation.
  • For the holidays, isn't it. If they only did it before Christmas...
  • Well, as it's theorized the Milkyway has already swallowed others (reference missing), there should either be multiple black holes in our galaxy, or this provides a good estimation of how long it's been since that happened -- according to Einstein, of course.
  • Such a dance is expected to occur in our own Milky Way Galaxy in about 3 billion years, when it collides with the Andromeda Galaxy.

    I'll believe that when I see it...

  • 3 billion years for a species to not kill itself long enough to escape this galaxy, lest all life on it perish?
    • by khallow (566160)
      All life on what? The species in question? And how does a galactic collision threaten all life in the galaxies involved?
      • by dryeo (100693)

        When galaxies collided it can trigger a huge amount of star formation due to the gas clouds colliding. Many of these stars are blue super giants that put out large amounts of radiation as well as having a tendency to supernova.
        This may raise the galactic radiation levels high enough to make most of the galaxy uninhabitable.
        Also the odds of close passes by stars increases therefore increasing the odds of habitable planets orbits getting perturbed.
        This would be most pronounced in the main part of the galaxy a

    • 3 billion years for a species to not kill itself long enough to escape this galaxy, lest all life on it perish?

      I expect that the cockroaches will be just fine where ever they end up.

  • 1) nearly every galaxy has a central super-massive black hole 2) galaxies commonly collide and merge to form new, more massive galaxies. [...] The two black holes gradually in-spiral toward the center of this galaxy, engaging in a gravitational tug-of-war with the surrounding stars.

    If this was a comment on the life of corporations, I would mod it "Insightful" (just substitue "galaxy" with "corporation" and "back hole" with "CEO").

    Just goes to show you, micro and macro-scale ecology is eeringly similar. I think we need a lecture on fractals and how they apply to this situation.

  • When the galaxies collide , what effect does it have on the inhabiting planets inside that galaxy, or is it something you would not feel, just all of a sudden (like in a crowded gym...) you look up to see twice as many people (or in this case planets and stars) then before?

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