Binary black holes terrorize quasar nucleus

By Phil Plait | March 4, 2009 11:00 am

Astronomers Todd Boroson and Tod Lauer have found what appears to be the best candidate seen for a tightly bound binary black hole, a close-knit duo of death in the center of a quasar. They sifted through over 17,000 quasar signatures to find this rare pair, sitting in the center of quasar SDSS 153636.22+044127.0 at a distance of about 4 billion light years from Earth.

Binary black holes

Although many double black holes are known (for example, NGC 6240 and 3C 75) — remnants of ancient galactic mergers, two galaxies colliding and eventually forming a single, bigger galaxy — these are widely-spaced pairs (30,000 and 10,000 light years apart, respectively, for NGC 6240 and 3C 75), and while it’s likely that in those cases the black holes orbit each other, it’s not completely certain.

In this new case, while it’s still not 100% rock-solid certain the two holes orbit one another, it’s very, very likely. First, by examining the redshifts carefully, Boroson and Lauer determined the two black holes are at the same distance from Earth. Second, they are separated by a very small amount: only about 1/3 of a light year separates the two monsters, making it incredibly unlikely they are unaffiliated.

And unlike other black hole binary candidates seen before, this pair’s authenticity is testable! They are so close and moving so rapidly — 6000 kilometers per second, an appreciable fraction of the speed of light — that the orbital period of the two is only about 100 years. Examining them again in just a few years should reveal their orbital motion around each other, clinching their marriage.

I’ll note that the two black holes are so close together that even the most powerful telescopes in the world would see them as a single object (in fact, the astronomers plan to take Hubble observations to see if they can resolve the pair or not; they expect they cannot which will further support their claim that this is a single system). We know there are two there because of their spectra. Imagine matter swirling around a black hole, and imagine further it emits a very narrow color range of, say, yellow light. As it orbits the black hole, it will sometimes be headed toward us, and sometimes away. The Doppler shift changes the color of the light, red and blue-shifting it over the course of the orbit. There are animations on an ESA page that may help you understand this. In those videos, sound is used as an analogy for color — lower pitch is redder light, and higher pitch is bluer light.

But there’s a lot of matter circling the drain of a black hole, forming a disk. We see red shifted light from the all the material in disk heading away from us, and blue shifting from the material in the disk headed toward us. We see all of this at the same time, so instead of a single color of light from the disk, it gets smeared out by that motion, forming essentially a bell curve (no, you won’t be graded on this). That curve, called a broadened line, is the signature of the black hole.

What Boroson and Lauer saw were two such broad line regions in the spectra, indicating two black holes. What’s cool too is that the mass of the black hole affects how broad the line is; the more massive it is, the more powerful its gravity, the faster material moves, so the broader the Doppler shift is. By carefully examining the broadening, they were able to determine that the black holes had masses of 20 million and 1 billion times the mass of the Sun.

That’s pretty hefty; the black hole in the center of our Milky Way galaxy is only about 4 million solar masses. These guys are real bruisers.

So it’s a pretty safe call that this really is a binary pair of black holes, two gaping maws of death circling each other at a distance of about 3 trillion kilometers, each supermassive and actively consuming material. They formed their bond when their parent galaxies collided eons ago, and eventually, billions or possibly hundreds of billions of years from now, these two giant black holes will merge themselves, swallowing each other and forming a single object with their combined mass. That’s one reason these beasts are so rare: they eat each other, leaving behind a single black hole. It was only through foresight, planning, and hard work that this pair was found at all. There may not be many more like them in the whole Universe, so every one we find gives us precious insight into the clockwork process of the cosmos itself.

Image credit: p. Marenfeld and NOAO/AURA/NSF.

CATEGORIZED UNDER: Astronomy, Cool stuff

Comments (90)

  1. Todd W.

    I wonder how long it will be before someone pops in saying one or more of the following:

    * Black holes don’t exist
    * Gravity doesn’t exist
    * Electromagnetism/plasma physics explains this perfectly

  2. ND

    Todd W.

    I think our friend has given up on BA. But never say never.

  3. Todd W.

    @ND

    Well, if he does come back, I hope he’ll finally get around to answering the questions I posed to him.

  4. So, should these two monsters smash into each other, do you think there will be a chance to detect the “gravity waves” that we’ve been looking for? It’s funny that we actually know LESS about things like gravity than we do evolution, yet there is very little public debate on it…

    I do hope that Anaconda just stays away, I am tired of him wasting electrons…

  5. Todd W.

    @Larian

    Now you did it. You said his name. He’s sure to turn up, now. It’s kinda like Candyman or Betelgeuse. :)

  6. ND

    Not only did you mention the name, you mentioned gravitational waves.

    Anyway, I’d love know know what sort of gravitational waves this pair could set off. I’m really looking forward to results from LIGO as it gets more sensitive and other upcoming GW experiments.

  7. rob

    uh…black holes don’t exist.

    heh.

  8. dre

    So… do you think there’s a nice Lagrangian point between those two monsters, where you could hang out, take in the view, get a few x-rays of your teeth done?

  9. John

    Wait…what are the arguments behind the claim that black holes and gravity don’t exist?

  10. Wait, I am confused. Is the quasar the binary pair of black holes or are they orbiting the quasar? And if so, isn’t that a pair of black holes orbting another black hole?

  11. So are these Black Holes “enemy combatants”?

    /snark

    J/P=?

  12. Matt W

    John, usually a bunch of mined quotes, then hand-waving insistence that “electromagnetism/plasma physics explains this perfectly, because I say so”.

  13. Todd W.

    @John (not John Paradox)

    I don’t pretend to understand the reasoning of EU/PC proponents.

  14. Chris A.

    @Todd W.
    “Now you did it. You said his name. He’s sure to turn up, now. It’s kinda like Candyman or Betelgeuse.”

    [D&D nerd]

    Or Asmodeus.

    And yeah, I’m talkin’ old school: AD&D version 1 y’all, first edition Monster Manual. ‘Cause that’s how I roll (my saving throws).

    [/D&D nerd]

  15. Todd W.

    @Chris A.

    Great. Now the blog will be possessed by a demon.

  16. IVAN3MAN

    Hey, Larian and Todd W.! If you’re interested (ND already knows this), Anaconda and OilIsMastery are over at Universe Today spouting their usual jabberwocky about the “myth of gravity”. :roll:

  17. Todd W.

    @IVAN3MAN

    Meh. Probably nothing we all haven’t heard before.

  18. ND

    dre,

    I don’t think you’ll be around long enough to enjoy those lovely x-rays of your teeth :)

  19. Thor

    Thought I was reading The Onion when i saw the title.

  20. For some reason, CENTAF thinks that Universe Today is too educational to allow me to paruse it during work hours. And let’s be honest, reading their rantings can actually cause braim bamage. I need all the neurons I can spare for my alcohol research!

  21. Terry

    JoeSmithCA: A quasar is an active galactic nucleus, not a single entity. It is powered by a massive black hole, or in this case a binary black hole system.

    Terry

  22. Todd W.

    @IVAN3MAN

    And speaking of OiM, I remember one thread a while back that he posted that gravity doesn’t exist. When I asked why we don’t go flying off into space, he replied, “Because opposites attract.” I followed up by asking why a wee tiny magnet can counteract the apparently large electromagnetic attraction that keeps things on the planet, and he replied, “Because like charges repel.”

    I never did get that clarified.

  23. Gravity doesn’t exist…the Universe just sucks in all directions :-)

  24. Torbjörn Larsson, OM

    what are the arguments behind the claim that black holes and gravity don’t exist?

    I believe they are the same as when it is claimed that astronomers (or other physicists) can’t model aspects of a plasma as a gas when it is appropriate: it’s some dreamed up (i.e. fully unsubstantiated) idea that plasmas and EM interactions explains “everything” (i.e. everything that the plasma universe guy wants it to explain).

  25. Cheyenne

    It would really be just awesome if we could watch two active black holes actually merge together. And maybe if we got really lucky LIGO could pick up the gravitational waves directly.

  26. Dan

    This blog is likely to be eaten by a grue. :)

  27. QUASAR

    Aren’t black holes and quasars like, the most fascinating and also one of the dangerous things in the Universe?

  28. ND

    John Paradox,

    It’s hard to torture black holes when they don’t exist.

    Black holes are actually instruments of supressing in the halls of academia. Alternative theories on cosmology are held back to perpetuate dogma. And “black holes”, and other exotics, have been conjured up to accomplish this goal.

    /snark <— am I using this correctly?

  29. QUASAR

    And, approximately 4 billion light years away? That means that this happened nearly 4 billion years ago!

  30. IVAN3MAN

    Todd W.: “Meh. Probably nothing we all haven’t heard before.”

    You’re absolutely right! However, the Universe Today articles are very interesting; it’s a pity that the comments section seems to attract cranks and nutters, like a picnic attracts bloody flies and wasps!

  31. Universe Today excerpter

    twas brillig and the slithy toves did claim at Universe Today:

    “OilIsMastery says:

    Utterly absurd.

    If black holes suck in light, how did they detect and observe them? With a crystal ball?

    At 1/10 a parsec distance from eachother how come the massive black holes don’t fall on eachother by their overwhelming gravitational pull?

    The article alleges that material falls into black holes but at 1/10th of a parsec the black holes aren’t falling into eachother.

    Rather they are orbiting eachother regularly, thus defying Newton’s occult so-called law of gravitation.”

  32. Rob

    Those aren’t black holes. They are AIG’s profits

  33. Todd W.

    @Universe Today excerpter

    Ow. My brain just snapped.

  34. Charles Boyer

    @Rob “Those aren’t black holes. They are AIG’s profits”

    No sir, they are American tax dollars flowing into AIG coffers…at the rate of $7,667/sec.

  35. firemancarl

    So, when super-duper black holes merge, do they go on a feeding frenzy? I mean, AIG is going on one now and it just merged with another bailout.

  36. Torbjörn Larsson, OM

    Damn, my brain is so indoctrinated by education that it actively rejects anti-knowledge: I first read that as “Newton’s gravitational so-called law for occultation”.

    … and now my brain snapped too.

  37. bigjohn756

    Phil, how many eons ago did they collide?

  38. Davidlpf

    Please whatever you do, do not repeat do not try to think like OiM. getting close to the blackhole fine but there are some things that are just too horrifying for the human brain.

  39. ND

    I really, really did not want to bring attention to Oils/Anaconda on UT but you guys have to read this. It’s absolutely hillarious:

    http://www.universetoday.com/2009/03/04/astronomers-detect-two-black-holes-in-a-cosmic-dance/

  40. Brian

    What a fantastic find. The forces involved in that dance must be intense. Poor space-time continuum! Good thing it’s so stretchy.

  41. Phil wrote:

    “billions or possibly hundreds of billions of years from now”

    Waaaaaaaaaaait a minute! I thought that at the current rate of universal Inflation, in only 20 billion years the fabric of space will have flown so far apart that atoms will no longer be able to interact with each other.

  42. Anne

    Actually, we think that there may be many pairs of black holes even closer together than this. They will be too far away to see any light from, but for gravitational-wave detectors with sensitivity to waves with year-scale periods, they are expected to be the dominant signal. We are in fact building such a gravitational-wave detector: all you have to do is carefully time the pulses from a lot of pulsars; gravitational waves will produce variations in the arrival times that are correlated between different pulsars.

  43. Knurl

    @ND

    I couldn’t help checking it out. I read the thread in the mid-afternoon to find out what everybody was saying about Anaconda and OiM (I missed the stuff they did on this blog and have neither the time/interest to check out lunacy).

    OiM’s rants, especially about Newton’s “occult” science, lead me to wonder if this might be a new type of creationist attack . It seems to be an attack on the understanding of the universe.

    BTW. Somebody or other here either asks the questions I come up with before I do or gives an answer before I can find it. Some have high level expertise. That’s why I don’t post a comment very often, and I guess that makes me a “lurker”. But I do read most of the posts and appreciate the things that most commenters give me to think about. If an individual does not seek knowledge beyond what they know or what they think…..

  44. Greg in Austin

    QUASAR said,

    “Aren’t black holes and quasars like, the most fascinating and also one of the dangerous things in the Universe?”

    Not to humans. The most dangerous thing to humans is driving a car.

    8)

  45. Greg in Austin

    QUASAR said,

    “And, approximately 4 billion light years away? That means that this happened nearly 4 billion years ago!”

    Hey, Captain Obvious, did you learn something today?

    light-year

    –noun
    1. Astronomy. the distance traversed by light in one mean solar year, about 5.88 trillion mi. (9.46 trillion km): used as a unit in measuring stellar distances. Abbreviation: lt-yr

    8)

  46. Pouria

    Offtopic:
    Reading comments such as those made by OIM and Anaconda make me truly belive humanity is headed for inevitable doom. Is it just me or have these people multiplied the past few years?

    on topic:
    Cool!

  47. Pieter Kok

    @ UT thread: Oh dear…
    In some sense it is fascinating to read, because it clearly demonstrates the impossibility of meaningful communication between people who have wildly different world views. It goes a long way to explain the disconnect in the political discourse in the US, and it bodes terribly badly for any future encounters with aliens.

  48. What’s the name of the spacetime used to model a binary pair of black holes?

    I imagine that the Kerr geometry approximates the system around its center of mass. But wow, that would be a really twisted Kerry solution — over a billion solar masses spinning at relativistic speeds!

  49. Nigel Depledge

    Joe Smith CA said:

    Wait, I am confused. Is the quasar the binary pair of black holes or are they orbiting the quasar? And if so, isn’t that a pair of black holes orbting another black hole?

    A quasar is a galaxy with an active black hole at its centre.

    Or, in this case, a galaxy with two black holes at its centre.

    However, quasars are all so far away that, until fairly recently, the active black hole was all we could see. Hence the name, Quasi-Stellar object (QSO, or Quasar).

  50. Nigel Depledge

    Greg in Austin said:

    The most dangerous thing to humans is driving a car.

    No, no, the most dangerous thing to humans is being on a road with other humans driving a car / cars.

  51. Greg in Austin

    @Nigel,

    Of course, I could have been more specific. Most people would get around safely if there were nobody else on the road, unless of course the only person on the road was a 16-year-old boy driving a Mustang GT. ;)

    A relative of mine once told me a story of a great-grandparent who owned the 2nd automobile ever sold in Texas. By sheer luck, that great-grandparent just so happened to have an accident with the driver of the first car ever sold in Texas.

    8)

  52. Nigel Depledge

    Greg in Ausitn said:

    Of course, I could have been more specific. Most people would get around safely if there were nobody else on the road, unless of course the only person on the road was a 16-year-old boy driving a Mustang GT.

    Hmmm … what’s that, about 600 horses in a 2-ton car?

    How about the Bugatti Veyron instead? 1000 bhp in a car weighing just over a ton.

    A relative of mine once told me a story of a great-grandparent who owned the 2nd automobile ever sold in Texas. By sheer luck, that great-grandparent just so happened to have an accident with the driver of the first car ever sold in Texas.

    Heh. That must have taken some doing.

  53. Cheyenne

    @Nigel – If you like the Veyron you should watch the last episode of Top Gear. Stig finally was able to take it out for a timed lap.

    That car is a beast.

  54. Gary Ansorge

    In Saudi Arabia, in the late 1970s, when Saudi Arabs finally had access to cars, their favorite expression seemed to be “Allah Akbar”,,,,just before running their Datsun at 120 miles/hr under the front end of a Mercedes dump truck,,,

    I guess we all have a need for speed, as in, “Finally, I can out run Abdullahs camel,,,”
    ,,,or, in Texas, it would be “,,,Joes horse drawn carriage,,,”

    Snark!!!

    GAry 7

  55. Sorry, firemancarl, but black holes are much easier to understand than insurance or the stock market.

  56. Joe Meils

    I was reading Phil’s description of this, and I had a sudden feeling of deja vu…

    Has anyone else ever read a novel by David Gerrold called, “The Galactic Whirlpool?” It was one of the earliest “Star Trek” tie in books… but he describes something very much like this.

  57. Chris A.

    @Bryan:
    The reason there are names for various spacetime geometries in GR (e.g. Schwarzschild, Kerr, Kerr-Newman) is because they are exact (analytic) solutions of the Einstein field equations. Something as complex as this won’t have an analytic solution, and thus probably won’t get named. Part of what makes solving GR hard is that it is highly non-linear, i.e. the things that cause the curvature of spacetime (i.e. mass and energy) are themselves subject to the effects of curved spacetime. Time to break out the numerical approximation code and the supercomputer!

  58. DrFlimmer

    I cannot just go on without leaving a comment:

    I consider this “two” quasars to be ejected galacitic nuclei that are now combined by intergalactic Berkeland currents! Definitly, without any doubt!

    Now, I feel better… and now I will go on to the UT forum…

    Greetings!

  59. Brian

    I’m getting a series of really interesting questions out of this. My knowledge of Relativity and Black Holes is somewhat limited, but here goes:

    Would 2 singularities ever truly merge? Or is there some mathematically provable notion that they would forever remain separate, locked in an ever-tighter orbit? Kind of like a Space-Time version of Zeno’s Paradox?

    What happens to the event horizons during the early stages of the merger process? Would they extend outwards towards the other mass? Perhaps retract inwards, due to opposing gravity fields? Or are they completely unaffected (seems unlikely)?

    If orbiting black holes generate gravity waves and waves are a form of energy, wouldn’t those gravity waves be getting their energy directly from the masses of the black holes? Is this a way for a black hole to lose mass, like Hawking radiation? If so, is this a significant energy loss to the black holes? Or is this over-reaching, and all that radiated energy is simply drawing down the kinetic energy of the holes?

    Would the merged black hole rotate, having gotten a big kick from the orbital motions of the original pair? I seem to recall that a rotating hole had a singularity that was a ring, rather than a point (or was it a double event horizon?).

    Wasn’t there some idea that an energetic phenomenon (Gamma Ray Bursts?) was the result of black hole mergers? Or was it simply black holes consuming large masses like stars?

    So many interesting questions!

  60. DrFlimmer

    Many interesting questions, indeed! But I do not have many answer for you, at least a few.

    I think that the singularities will merge, yielding a singularity with more mass (the combined masses from the two singularities). But I am guessing; on the other hand I cannot imagine a reason to prevent the merger.

    An event horizon is not a membrane or physical object. The only thing that will happen is that it will grow when the singularities are close enough to each other (probably when they are “inside” the other’s event horizon). I don’t know if you will ever have a sphere; possibly the two spheres just combine to the bigger sphere.
    But what do you mean with “opposing gravity fields”? Hopefully you don’t refer to something like “anti-gravity”, what is nonexistent.

    Gravity waves (AFAIK) are just the product of the “released” angular momentum. It should not affect the mass of the black hole(s). They are just colliding due to gravity waves (probably one could call it another form of friction ;) ).

    Since both black holes are most likely rotating the resulting black hole should rotate as well. And if I recall correctly a rotating BH has a singularity that is a ring AND more than one horizons, since only the inner one is the “true” event horizon and the outer one defines something that is called the ergo-sphere, out of which particles can still escape (and have some other weird effects).

    I don’t know if a black hole merger can cause a GRB, since you merge two singularities and two event horizons, but I don’t want to exclude that possibility.

    In fact, most of my answer are more or less speculations from what I know about black holes. But most of my knowledge depends on Schwartzschild black holes, meaning nonrotating ones. But, as I said, probably every BH is rotating so the situations can be more difficult and complicated. Nevertheless, your questions are interesting and I’d love to know more about those big monsters.

  61. IVAN3MAN

    DrFlimmer, are you familiar with GRS 1915+105? It is the heaviest of the stellar black holes so far known in the Milky Way Galaxy, with 10 to 18 times the mass of the Sun, and it appears that the black hole may rotate at 1,150 times per second! That is approaching the theoretical upper limit! Cool!

  62. DrFlimmer

    No, I haven’t met that specific black hole personally :D
    But I wonder why there should be an upper limit for the rotational period of a black hole since it should not “rip itself apart” like a neutron star. Probabaly I find some time to find out more about that.

  63. IVAN3MAN

    DrFlimmer: “No, I haven’t met that specific black hole personally.”

    Heh. So, you Germans do have a sense of humour, then?! :-)

    DrFlimmer: “But I wonder why there should be an upper limit for the rotational period of a black hole since it should not “rip itself apart” like a neutron star[?]”

    Remember that the Universal speed limit is c — 299,792,458 metres/second (exactly). So, let’s assume a spherical cow; if a reference point on the equator of the ‘spherical cow’ in question is travelling close to the speed of light, as it is rotating at 1,150 times per second around its axis, the equatorial circumference of the ‘spherical cow’ would be limited to:
    299,792,458 / 1,150 = 260.689 km maximum.

    Therefore, the maximum diameter of the ‘spherical cow’ would be:
    260.689 / π = 82.980 km — about the size of Pandora, a satellite of Saturn.

    Q.E.D. :-)

  64. DrFlimmer

    I thought the British humour is the one that is known to be very special ;) (On the other hand: Monty Python is absolutly fantastic!!!) So, yes, Germans can have a sense of humour, why did you think otherwise?

    @ Ivan3man AND also @ Brian
    After a few hours of internet research I finally took the book “An Introduction to modern Astrophysics” (2nd edition) by Carroll & Ostlie (probably THE standard literature for astrophysics students). Page 640 is quite interesting:

    “There is a firm upper limit for a rotating black hole’s angular momentum given by L(max)=GM^2/c.” (where G is the gravitational constant, M the mass and c the speed of light)
    “If the angular momentum of a rotating black hole were to exceed this limit, there would be no event horizon and a naked singularity would appear, in violation of the Law of Cosmic Censorship.”

    So there is, indeed, that upper limit. Sadly the book doesn’t give an explanation why the event horizon would vanish. Probably it has to do with complicate mathematical stuff of the Kerr solution of the Einstein equation of GR. But I don’t know that – probably someone else? ;) Maybe I check Carroll’s “Spacetime and Geometry” (this is Sean Carroll, not the same Carroll as above; he is named Bradley ;) ), but not now.

    But the text goes on about “frame dragging”:

    “The rotation has distorted the central singularity from a point into a flat ring, and the event horizon has assumed the shape of an ellipsoid. The figure [in the book] also shows additional features caused by the rotation. As a massive object spins, it induces a rotation in the sorrounding spacetime, a phenomenon known as fram dragging.
    […]
    Near a rotating black hole, frame dragging is so severe that there is a nonspherical region outside the event horizon called the ergosphere where any particle MUST move in the same direction that the black hole rotates. Spacetime within the ergosphere is rotating so rapidly that a particle would have to travel faster than the speed of light to remain at the same angular coordinate (viewed from the outside).
    […]
    The details of the singularity cannot be fully described until a theory of quantum gravity is found. The presence of a singularity seems assured, however. In 1965 an English mathematician, Roger Penrose, proved that EVERY complete gravitational collapse must form a singularity.”

  65. DrFlimmer: “So, yes, Germans can have a sense of humour, why did you think otherwise?”

    Oh, just stereotypical British viewpoint of Germans as hardworking, but humourless, and of the French as riding around on bicycles, wearing a black beret, a black & white striped jersey, and with onions around their necks. :-)

    @ DrFlimmer,

    The rotation has distorted the central singularity from a point into a flat ring, and the event horizon has assumed the shape of an ellipsoid. The figure [in the book] also shows additional features caused by the rotation. As a massive object spins, it induces a rotation in the surrounding space-time, a phenomenon known as frame dragging.

    Interesting! Wikipedia has an article on Ergosphere (click on my name for the link) that refers to “frame-dragging” and an illustration of an oblate spheroid (ellipsoid) ergosphere around the event horizon of a rotating black hole.

  66. DrFlimmer

    That graphic is more or less the same as in the book, so you get an idea ;). But the book does also contain a “line” representing the ringed singularity inside the event horizon.

    Btw: humourless Germans? Well, the British humour is, say, legendary here in Germany, too. ;) The same prejudices everywhere….

  67. DrFlimmer, I’m glad to hear that you like Monty Python! Click on my name for the link to the Official Monty Python Web-site: PYTHONLINE. Also, make sure that you buy The Complete Monty Python’s Flying Circus: Collector’s Edition DVD Mega-box-set of the entire series.

  68. DrFlimmer

    Ivan3man, thanks for the advice, probably I can place it on the next list of wishes for christmas. ;)
    I own the three movies already. Do you know that the Germans renamed “the holy Grail” as “The knights of the coconut” (Die Ritter der Kokosnuss)? Also a quite apposite name, I think.
    “Spamalot” is currently presented in Cologne, just 100km from where I live (so I am not the other German stereotype as a fat, wheat bear drinking bavarian, only eating “bratwurst and sauerkraut” :D ).
    We are working for international understanding, aren’t we?

  69. Brian

    DrFlimmer: Thanks for the reply. I appreciate any effort to answer my questions.

    No, I wasn’t referring to anti-gravity when I said “opposing gravitational fields”. I merely extended the concept of a Lagrange point between the Earth and the Sun to this (putative) binary black hole system. There ought to be a point somewhere between the 2 holes where their gravity cancels out.

    These two holes are rather mismatched in terms of their mass. It occurred to me that the gravity cancellation point could actually be inside the “normal” event horizon of the smaller hole. Thus a conceptual reason for a dimple in an otherwise spherical event horizon.

    On the other hand, if gravity is an attractive force (I know, I know, that’s not 4-D S-T thinking…) shouldn’t the 2 masses distend and distort towards one another, like the Earth and Moon? And, since there’s nothing left of the masses except a pair of singularities and gravity wells, won’t that event horizon bulge outwards?

    However I’m having trouble choosing. I think the reason is that I’m shifting conceptual frames of reference, between Newtonian ideas and Relativistic ideas. When I use full-on field thinking, I talk myself into the idea that Lagrange points don’t exist at all, anywhere, which I know is not true!

    The essential question remains: Is the merging event horizon an Innie, or an Outie? Or is it completely unmoved?

  70. DrFlimmer

    It’s just guess: I say they are not affected at all!

  71. IVAN3MAN

    DrFlimmer:

    … so I am not the other German stereotype as a fat, wheat bear drinking bavarian, only eating “bratwurst and sauerkraut”.

    You left out the “lederhosen wearing” bit. :-)

  72. DrFlimmer

    Since I am a great supporter of the soccer club “Borussia Dortmund” (you might heard of it, they won the Champions League in 1997; I have a seasonal ticket :) ) I am accustomed to sing

    “Zieht den Bayern die Lederhosen aus!”

    (probably a good translation is “take the leather trousers off the Bavarians”, but while I read it, I think this sounds rather stupid and wrong ;) ) when we have a match against “Bayern München” (Munich).

    So, I should have known!!

    Btw: in about 13min (9:00 pm MET) they show “Monty Python and the holy grail” on TV. Maybe I watch my DvD.

  73. DrFlimmer, can you answer one of the timeless questions of science: What is the airspeed velocity of an unladen swallow?

    Click on my name to find out.

  74. DrFlimmer

    At first, I just wanted to answer with the counter question, but clicking on your named served well. Thanks :) .

    But the movie is absolutly… well…. great. :D Even the German synchronization.

    Ni!

  75. IVAN3MAN

    DrFlimmer, wir wünschen ein Gebüsch!

    Is that the correct translation?

  76. DrFlimmer

    You can say it that way! I don’t know how they really did it, right now, but I love that scene!

  77. IVAN3MAN
  78. DrFlimmer

    “Wir wollen … ein schönes Gebüsch!”

    NI!

  79. IVAN3MAN

    My Babel Fish translator reads: “We want beautiful bushes!”

    NI!

  80. DrFlimmer

    Let me call it the “freedom of synchronization” (sounds like a bill of Goerge W. Bush) ;)

    Eki-eki-eki-*what-is-this-last-sound?*

  81. According to Wikipedia (The Font of All Knowledge!), the collector’s edition DVD of Monty Python and the Holy Grail has the “script” subtitles for that bit in the Knights Who Say Ni! (click on my name) scene as: “Ekke Ekke Ekke Ekke P’tang Zoo Boing”!

  82. @Brian “Would 2 singularities ever truly merge?”

    Good question. From the point of view of a “clock” maintained at either black hole singularity they will. From the point of view of a remote observer watching the merger it will take an infinite amount of time.

    “What happens to the event horizons during the early stages of the merger process? Would they extend outwards towards the other mass?”

    The event horizons are not physical objects so there should be no effects similar to what happens when two physical objects merge (e.g., turbulence, etc.).

    “If orbiting black holes generate gravity waves and waves are a form of energy, wouldn’t those gravity waves be getting their energy directly from the masses of the black holes? Is this a way for a black hole to lose mass, like Hawking radiation?”

    It’s my understanding that the energy contained in the gravitational waves comes from the initial kinectic energy of the two black holes.

    “If so, is this a significant energy loss to the black holes?”

    Probably not, in this case the kinetic energy of the smaller of the black holes is 7.2E50 joules but its rest energy is 3.6E54, 5000 times greater.

    “Would the merged black hole rotate, having gotten a big kick from the orbital motions of the original pair?”

    They are probably both rotation to begin with. After the merger the resulting angular momentum vector is the vector sum of the initial angular momentum vectors (using the parallelogram rule).

    “I seem to recall that a rotating hole had a singularity that was a ring, rather than a point (or was it a double event horizon?).”

    I think that’s probably true. Of course any attempts to go inside the event horizon and verify this are likely to be fruitless.

    “Wasn’t there some idea that an energetic phenomenon (Gamma Ray Bursts?) was the result of black hole mergers? Or was it simply black holes consuming large masses like stars?”

    GRBs are thought to be coming from massive stars during black hole formation, not from swallowing stars although that probably would be an energetic event also.

  83. Keith

    My question is do quasars suck in things like blackholes?

  84. Keith

    please answer ASAP!

  85. Keith

    My ? is do quasars suck in things like black holes
    reply ASAP!

  86. I hope this thread is not completely dead!

    (Brian) Q: “What happens to the event horizons during the early stages of the merger process? Would they extend outwards towards the other mass?”
    (Tom) A: The event horizons are not physical objects so there should be no effects similar to what happens when two physical objects merge (e.g., turbulence, etc.).

    Brian’s question is similar to the one that I wanted to ask. I don’t know if you are correct Tom, that there would be no effect to the Even Horizons as the two singularities approach each other in a merger.

    Even though both objects are super massive, the pull they exert on each other should still create an area of zero gravity at a specific location between the objects relative to their masses. For example, the SOHO (Solar and Heliospheric Observatory) Satellite orbits at a distance between the Earth and the Sun where the two body’s gravities “balance each other out” so that the pull on the satellite is equal in both directions.

    Regardless of their masses, there should be a similar zone of zero gravity that exists between these two black holes where the pull from each black hole is equal but in opposite directions.
    Considering that the Event Horizon is simply a threshold where the gravitational pull of a black hole becomes so great that nothing can escape, as these two monsters approach each other, shouldn’t the event horizons retreat inward towards their centers by this zero G zone between the two masses? If there is no gravity, relatively then there can be no Event Horizon, right? I understand that this zone would become increasingly narrow or small as the two masses move inward towards each other, but it should still be there regardless of it’s size.

    I know I must be wrong in this conclusion but it is something that I have been thinking about as I’ve been considering whether Newton’s Shell Theorem, should also be applied to Black Holes. Just as there is zero gravity at the center of the Earth and Sun, because all the mass of these objects goes out in all directions away from the center, shouldn’t the same be true for a Black Hole and doesn’t that imply that there would be no singularity at the center of a black hole?

  87. Rich Mingin

    This makes me wonder; Those masses are so very high, I wonder if there is a conversion point for black holes. Not a scientific term, just one I’ve been using. Conversion point: At around solar masses, dying stars swell and red giant, then shrink and brown out. At the conversion point, the stellar mass is enough to nova or supernova. Also, there’s a point further along the stellar mass scale where black hole formation becomes possible, then likely, then inevitable, according to our models.

    Is there another point, further up the scale, where a supermassive black hole of, say, a trillion solar masses does something new, and even weirder? Quantum breakdowns, neutronium, something weirder??

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