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Space Science

Milky Way Black Hole Could Reignite 117

Posted by kdawson
from the tinfoil-umbrellas-might-help dept.
sciencehabit sends us to Sciencemag.org for an account of a survey of nearby galaxies that points to the possibility that once-quiescent galactic nuclei could wake up and become active again. If the Milky Way's dormant black hole should become active, it could be bad news for life on Earth (and elsewhere in the neighborhood). The paper (PDF) is up on the arXiv.
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Milky Way Black Hole Could Reignite

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  • by Beavertank (1178717) on Thursday April 10, 2008 @11:31AM (#23025120)
    Remember kids, just like government mind control rays the gamma ray bursts generated by our galaxy's black hole center can be blocked by a tin foil hat.

    You may want a tin foil codpiece, too.
  • oblig. (Score:3, Funny)

    by Rob T Firefly (844560) on Thursday April 10, 2008 @11:31AM (#23025122) Homepage Journal
    What does.. God.. need.. with a starship?
    • Worst. Trek. Movie. Ever.
      • Re:oblig. (Score:5, Funny)

        by infonography (566403) on Thursday April 10, 2008 @03:04PM (#23028196) Homepage

        Worst. Trek. Movie. Ever.
        Don't be so hasty, there are plans for many more....
        • by sco08y (615665)

          Don't be so hasty, there are plans for many more....
          Without the pure awfulness that was Shatner, they'll just be derivative.
      • by LithiumX (717017)
        No... most regrettably, Insurrection has long-since beaten Final Frontier in the Worst Trek Movie Ever competition.

        The difference between the two, on my end, is that I've watched FF at least once since buying it. I have started Insurrection twice, but never got more than 30 minutes into it. It was that bad.

        Please note that the only reason I own either one is that I had two gaping holes in my Trek collection that had to be filled, regardless of how dirty I felt when I bought them.

        Final Frontier pr
        • So, you're saying that when your obsession causes you to fill your two gaping holes, it makes you feel dirty?

          Further, that you've only ever made it through 30m of the video? Twice?

          Sure you aren't talking about another industry?

          Just saying... ;-)
    • What does.. God.. need.. with a starship?
      I don't know about God, but I know the Puppeteers are bugging out even as we speak.

      http://en.wikipedia.org/wiki/Pierson's_Puppeteer [wikipedia.org]

      but they don't bother with spaceships either they use planets....
    • by rubycodez (864176)
      "What does...God..need...with an ark?" -- Noah's Neighbor
  • by sm62704 (957197) on Thursday April 10, 2008 @11:31AM (#23025136) Journal
    Darn, and I never EVER rtfa, but the summary made it necessary. So for my fellow slashdotters who hate to RTFA, what they mean by "reignite" is to turn into a quasar. The way the black hole could turn into a quasar is for the galaxy to collide with another galaxy.

    I don't think we have anything to worry about. Nothing to see here (and if it happened, nobody to see it)
    • by Dan East (318230) on Thursday April 10, 2008 @11:36AM (#23025216) Homepage Journal
      "The way the black hole could turn into a quasar is for the galaxy to collide with another galaxy."

      That's not what the article says:
      It's not understood what is causing the black holes to become newly active, because in most cases there is no evidence of collisions or mergers.
      • To be fair, it is still a way and not the (only) way that we know of now.
      • Only way for black holes to become "more active" is for more mass to fall into it. Don't know what they're talking about...
      • by kesuki (321456)
        "It's not understood what is causing the black holes to become newly active, because in most cases there is no evidence of collisions or mergers."

        Clearly it's the dark matter that nobody has figured out where it is or where it's going that's colliding with all these black holes making them quasars.

        In theory a super large gravity well that's tightly compressed shouldn't change into a quasar with no reason. After-all with no impact, that would require matter escaping the singularity...

        But FWIW i doubt it wou
        • by kesuki (321456)
          Should have wiki'd

          "Current measurements suggest the Andromeda Galaxy is approaching us at 100 to 140 kilometers per second. The Milky Way may collide with it in 3 to 4 billion years, depending on the importance of unknown lateral components to the galaxies' relative motion. If they collide, it is thought that the Sun and the other stars in the Milky Way will probably not collide with the stars of the Andromeda Galaxy, but that the two galaxies will merge to form a single elliptical galaxy over the course of
    • Re: (Score:3, Insightful)

      by John Hasler (414242)
      > ...what they mean by "reignite" is to turn into a quasar. The way the black hole could
      > turn into a quasar is for the galaxy to collide with another galaxy.

      You didn't RTFA very well. The point is that they have found galaxies whose black holes have reignited without there being any evidence of a collision.
    • Unfortunately, your lack of practice in reading articles is apparent in your attempted explanation. I am no expert on the subject matter, but even I know enough to recognize that you misunderstood what they are saying.

      Actually, the main message I get from the article is how complex the universe is, and how little is known, even by the most knowledgeable, about how these mechanisms work.

    • by A nonymous Coward (7548) * on Thursday April 10, 2008 @12:30PM (#23025982)

      Nothing to see here (and if it happened, nobody to see it)
      Move along, move along.
    • Feed Me (Score:4, Informative)

      by iamlucky13 (795185) on Thursday April 10, 2008 @02:53PM (#23028090)
      For a black hole to be active, it needs stuff falling into it...gas, dust, stars if you're unlucky. The stuff heats up to an extraordinary temperature due to friction as it falls in. To be hazardous at our distance of 25,000 light-years from the galactic center, it has to be quite a bit of matter falling in for a harmful intensity of radiation.

      Our galaxy's black hole, Sagittarius-A, is not considered active, although it does have some weak emissions, primarily at harmless infrared and radio wavelengths consistent with a very small accretion disc. The nearest star to the black hole is estimated to be about 70 times as far away from it as it would need to be for the gravitational forces to remove significant amounts of material from the star. It also has an orbital period of 15 years, so it would take a long time and a significant perturbance to fall significantly close. It doesn't seem likely at all that it would become active in the foreseeable future.
      • Our galaxy's black hole, Sagittarius-A, is not considered active, although it does have some weak emissions, primarily at harmless infrared and radio wavelengths consistent with a very small accretion disc. The nearest star to the black hole is estimated to be about 70 times as far away from it as it would need to be for the gravitational forces to remove significant amounts of material from the star. It also has an orbital period of 15 years, so it would take a long time and a significant perturbance to fa
    • Re: (Score:3, Informative)

      by DynaSoar (714234)

      Darn, and I never EVER rtfa, but the summary made it necessary. So for my fellow slashdotters who hate to RTFA, what they mean by "reignite" is to turn into a quasar. The way the black hole could turn into a quasar is for the galaxy to collide with another galaxy.

      I don't think we have anything to worry about. Nothing to see here (and if it happened, nobody to see it)

      Obviously there is something to see here. Us. Our sun was a member of a galaxy that was absorbed by the Milky Way. The evidence is in the fact that we do not orbit the center of this galaxy in the plane of its arms, but rather perform a wave-like motion alternatively above and below the center plane, passing through the plane in between peaks. A galactic collision could produce the effect noted in TFA, while simultaneously increasing interstellar gas and dust cloud densities, protecting the outer stars fro

      • by Sibko (1036168)

        Obviously there is something to see here. Us. Our sun was a member of a galaxy that was absorbed by the Milky Way. The evidence is in the fact that we do not orbit the center of this galaxy in the plane of its arms, but rather perform a wave-like motion alternatively above and below the center plane, passing through the plane in between peaks. A galactic collision could produce the effect noted in TFA, while simultaneously increasing interstellar gas and dust cloud densities, protecting the outer stars from the radiation produced (as well as forcing new star production)

        Yeah, this was in a slashdot story awhile back I think. It was pretty quickly debunked by Bad Astronomy: [badastronomy.com]

        [Opening paragraph in above link.] Note: I generally don't do a thorough debunking of pseudoscientific nonsense on the blog, and instead relegate that to the main site. But I decided to do this on the blog, knowing that more people would read it than if I put it on the main site and linked to it from the blog. So here it is. Bon appetit.

    • by sjames (1099)

      So that's what Elvon [paganlibrary.com] was talking about!

    • Consider the hypothesis about the layer of enriched iridium in rocks formed at the boundary between the Triassic and Jurassic geologic periods and the associated extinction event... 200 million years ago.

      And the similar hypothesis about the layer of enriched iridium in rocks formed at the boundary between Cretaceous and those of the Tertiary periods and the associated extinction event ... 65.5 million years ago.

      Could that suggest an alternative to the "impact from an asteroid or comet" hypothesis? Could

  • by clonan (64380)
    I for one welcome our "new" glactic core Overloards!
  • by RichMan (8097) on Thursday April 10, 2008 @11:42AM (#23025280)
    So massive core explosions delivering a huge radiation wave are expected.

    Step 1:
        - invent scrith
    Step 2:
        - build Ringworld
    Step 3:
        - profit (sell real estate)
    • Re: (Score:3, Interesting)

      by PakProtector (115173)

      So massive core explosions delivering a huge radiation wave are expected. Step 1: - invent scrith Step 2: - build Ringworld Step 3: - profit (sell real estate)

      Dear Sir and/or Madam:

      Good Day. My name is Jack Brennan. You may call me Brennan-monster. I am writing on behalf of my Protector brethern. This letter constitutes a cease and desist notice. You have been publishing our trade secret, that is, our business plan. Please remove said plan from you website at once or face litigation.

      Sincerely yours, Jack Brennan

      • by fifedrum (611338)
        I always figured such a move to be more like, "I sense you are a threat and will now destroy your entire lineage. With my bare hands." rather than a C&D letter on paper
      • Re: (Score:2, Interesting)

        by Anonymous Coward
        Umm... Jack Brennan (AKA BrennanMonster) was trying to protect humanity from the Pak, and the Pak already made the Ringworld, so prior art, and all that... :)
        • We Protectors stick together.

          Now go away, or someone with Genetic Luck will come along and ruin this conversation by making it so that any further dialog entered into it will only work out in their favour.

          Jack Brennan

    • Rich Mann.

      Have you read Down in Flames?

    • by sco08y (615665)
      Step 0: raise rather a lot of venture capital
  • by mmell (832646) <mike.mell@gmail.com> on Thursday April 10, 2008 @11:43AM (#23025292)
    but it is intriguing. I'm always impressed when scientists come forward and admit that they've found something they didn't expect. It validates the scientific method and the people who apply it to research - whether it be mathematics, anthropology, physics, cosmology, . . .

    SO - not unlike the assertion (for example) that there's a large asteroid with Earth's name on it, this research seems to indicate that perhaps we should start studying this phenomenon now even if there's nothing we can do about it now. After all, much of our modern technology was understood to be impossible/impractical as little as a century ago; if we start looking now, perhaps we can devise a mechanism for the preservation of our species before we need it. Then again, when has humanity ever shown that much foresight?

    • Understanding something better could have a big reward. Maybe not avoiding that all the life in 30k light years from galaxy center is wiped out, of course (that is the core of the RTFA?), but think that that will not happen (soon, at least), and that we learn more... maybe we can use that to implement future technologies or even stop a very dangerous experiment at LHC.
      • "or even stop a very dangerous experiment at LHC."

        You DO know that particles with much higher velocities and energy levels than the LHC could ever produce interact with other particles every second in the upper atmosphere of Earth, and that no planet devouring quantum black holes have appeard and devoured the Earth, nor have any "strangelets" converted the Earth to its component bits.

        Oh, wait. Apparently no, you DON'T know.

        Stop listening to Art Bell (or whoever is in the chair at his radio program these day
        • Re: (Score:2, Interesting)

          by Mr. Slippery (47854)

          You DO know that particles with much higher velocities and energy levels than the LHC could ever produce interact with other particles every second in the upper atmosphere of Earth

          You DO know that such collisions involve one particle with high velocity impacting a particle at rest (relatively speaking) with respect to the earth, making the collision products scatter like billiard balls after a good break and thus taking them away from the planet in short order? As opposed to colliding two streams with o

          • Re: (Score:3, Interesting)

            ...the collision products scatter like billiard balls after a good break and thus taking them away from the planet in short order?

            It seems to me that a significant fraction of the collisions would produce particle showers pointed towards the ground. Even if 99% of the "evil bits" have momenta that don't allow them to settle into the earth, there's still a lot of evil bits (produced by incident particles with energies 10^4-10^6 times more energy than the LHC) over the last 4+ billion years that haven't des

            • It seems to me that a significant fraction of the collisions would produce particle showers pointed towards the ground.

              Sure. But the idea is that the particles so produced would be zipping along rapidly due to the momentum imparted by the collision, and would go right through the planet with a small chance of reacting with anything.

              • If neutrinos can and do interact with particles, I.E. pure water in the diverse detectors worldwide, then it appearsthat in the 4.5 billion years or so that there has been an Earth made of solid matter, and the 3 billion or so years there's been an atmosphere of one kind and another, there has yet to have been an "evil particle" that has interacted with terrestrial matter or atmosphere.

                Apparently, that "small chance" you posit is so small, as to be effectively zero.

                Thanks for playing! Vanna has some lovely
                • If neutrinos can and do interact with particles...

                  Uh, yes. So what? No one was talking about neutrinos.

                  in the 4.5 billion years or so...there has yet to have been an "evil particle" that has interacted with terrestrial matter or atmosphere.

                  In 4.5 billion years or so, I suspect there have been few if any collisions between particles with high but opposite velocities. How often does one high energy cosmic ray particle knock into another going the opposite direction?

                  Yes, lots of collisions between hi

                  • "
                    If neutrinos can and do interact with particles...

                    Uh, yes. So what? No one was talking about neutrinos.


                    It's called an analogy. Much like your very lame pool ball analogy. Except mine makes sense.

                    If neutrinos, virtually massless particles with no charge, can interact with matter to an extent they are routinely detectable, then these super high energy particle generated in the upper atmosphere, it's likely in that in 4.5 billion years, at some point, that quantum black holes have
                    • It's called an analogy.

                      No, it's called a non sequitur. Neutrinos, from man-made reactions or from natural ones, have not been seen to exist traveling at any velocity besides a whisker away from c. All neutrinos are equal.

                      The question here is not just whether weird dangerous particles could form, but with what velocity relative to the earth. If they can exist at all (and I'm not saying that they can) a non-evaporating micro black hole or a stranglet or a monopole at rest with respect to the earth is a

                    • You know what they say about arguing on the Internet and the Special Olympics?

                      YOU WIN!
  • Oh noes! (Score:2, Funny)

    by RabidMonkey (30447)
    If the terrorists get their hands on this, we're all doomed!

    Quick, invade something, anything!
    • Re: (Score:1, Offtopic)

      by Radish03 (248960)
      Quick, invade something, anything!

      Don't be so quick to invade! I say, we develop manned space travel so that we may send some of our elected leaders to meet with the black hole in its homeland of the galactic nucleus to discuss the situation.
      • by j_166 (1178463)
        "I say, we develop manned space travel so that we may send some of our elected leaders to meet with the black hole in its homeland of the galactic nucleus to discuss the situation."

        So what you're saying is we fight them over there so we don't have to fight them over here. Brilliant! You build the spaceship, I'll build the giant magnetic yellow support-the-troops ribbon. (Well, I won't really *build* it so much as I'll outsource the building of it to China).
    • by Culture20 (968837)
      If you invade the black hole, you'll only make it stronger.
  • by Gat0r30y (957941) on Thursday April 10, 2008 @12:07PM (#23025690) Homepage Journal
    From TFA it seems like somewhere between 20-40% of galaxies surveyed have active nuclei, but how do they know they reignited?

    It's not understood what is causing the black holes to become newly active, because in most cases there is no evidence of collisions or mergers.
    How could it be verified that despite the lack of a recent collision with another galaxy, these particular phenomenon were at some point dormant like ours, then reignited? How are they supporting this claim that these galactic nuclei must have spontaneously rekindled vs. they have been winding down from a collision very far in the past?

    There's just one problem: Astronomers have found quasarlike centers--called active galactic nuclei (AGN)--in some relatively nearby galaxies, which should be far too old to generate such energies.
    So they should be too old for this sort of behavior, but how are they verifying the time since the last collision? Another possibility is that these galaxies had a collision more recently right?
    • by HTH NE1 (675604) on Thursday April 10, 2008 @02:49PM (#23028026)

      How could it be verified that despite the lack of a recent collision with another galaxy, these particular phenomenon were at some point dormant like ours, then reignited?
      By the velocity vectors of surrounding matter affected by the blast? A collision would give the local matter directionality whereas a spontaneous reignition would send matter out in all directions uniformly.

      Haven't you watched CSI: Stellar Cartography Unit?
    • by antic (29198)
      Newbie question - things like galaxies colliding and black holes igniting and ungulfing galaxies - what sort of time scale would be involved with these events? If very high, I'm assuming that very high speeds are involved and that a drawn out event would simply stem from the sheer size of the objects in question?
  • by meringuoid (568297) on Thursday April 10, 2008 @12:11PM (#23025752)
    ... Well, shit. I'd nearly saved up enough to buy a General Products hull, and now it seems they've shut up shop and left town.
  • OK, so I've R'd TFA, and I've read what people have posted so far. But, I'm still too thick to get it.

    So, a quasar is an energetic black hole? Or it's kinda like a black hole, but different, and with more spinning and less dark?

    What is the black hole "doing" when it's not spraying high energy particles every where? What happens to turn a black hole into a quasar short of two colliding galaxies? We're now sure that there is a black hole in the center of all-if-not-most galaxies seems to be implied by thi
    • Re: (Score:3, Informative)

      by Stevecrox (962208)
      http://en.wikipedia.org/wiki/Quasar [wikipedia.org]

      Quasars are an effect created by the supermassive black holes at the centre of each galaxy, these black holes consume tremendous amounts of mater (something like 10 sun masses a year) the more solar masses they consume the brighter they are. Obviously there is only so much material than can be pulled in by the supermassive black hole, eventually all the material is either ejected as high intensity engery (the quaser pulses we can observe) or consumed by the black hole.
      • But this posits, without evidence, that the black holes in these galaxies in fact had run out of matter to pull in, before coming into contact with more, thus the re-ignite. It may just be that they never stopped being quasars and that some galaxies take longer for the matter to be pulled into the black hole than others. It may be that they never stopped being quasers and the theory on how long until the matter orbitting "should have been used up" is wrong.
  • The scary part is this thing could already be active and we just don't know it yet!

    The night sky would be pretty though.
  • by peter303 (12292) on Thursday April 10, 2008 @12:36PM (#23026080)
    Its 30K light yers away, so we wouldnt know for that long.
  • May 2008..... LHC Startup
  • by random coward (527722) on Thursday April 10, 2008 @12:50PM (#23026296)
    Quick summary of TFA: Scientists observe that the black holes at the center of galaxies were Quasars on far away galaxies. The one at the center of the Milky Way and other nerby galaxies were observed to not be Quasars. So they theorised that the black holes initially are quasars after galaxy formation, and they run out of fuel. New observations show that nearby galaxies do in fact have quasars. A scientist conjectured that it re-ignited. Better conjecture may be that the fuel source of those blackhole-quasars is more variable than previously thought.
    • by ceoyoyo (59147)
      That would be the most likely mechanism for reignition.

      Black hole eats everything in easy reach, goes dormant. New source of fuel builds up in the neighborhood, black hole starts eating again, and the galaxy "reignites".
  • Axis of Rotation (Score:2, Interesting)

    by FromellaSlob (813394)
    Don't active galactic nuclei fire out their "death rays" along the axis of rotation, ie perpedicular to the galactic disc, where we are.
  • I guess space as we know it [wikipedia.org] would have to upgrade to class 3 pretty quick...
  • by Alizarin Erythrosin (457981) on Thursday April 10, 2008 @02:09PM (#23027514)
    OK, here's my theory:

    We detect the presence of black holes at galactic centers by observing the stars whirling around said galactic center at high rates of speed, right? All those stars whirling around have mass, therefore, gravity. Other stars moving around, maybe not as near to the galactic center, also have gravity. All this movement and such may attract, due to gravitational pull, a cloud of gas somewhere nearby. Slowly it gets pulled by the stars' gravity, until it gets into the gravitational pull of the black hole. Quasar'd!
  • Biologist are reporting that all of the dolphins have mysteriously vanished from the face of the earth.
  • Sure, it may seem academic now, but in just 3e9 years, our galaxy is going to merge with the Andromeda galaxy(http://en.wikipedia.org/wiki/Andromeda-Milky_Way_collision [wikipedia.org]). That would re-ignite re-ignite the merged black holes, and we'd have to move to a better neighborhood.
  • OK, so if it does reignite, what the hell are we going to do about it? Lob a tac nuke or something? Waitaminit....
  • It seems like I read a sci-fi short story along these lines. Only I don't think it was a "black hole reignition". It was a "sun-like" object, only on a much larger scale. Scientists had verified it's existence and determined that, coincidentally, the first light from that object would soon reach earth (I don't know how they discovered it before the light from it reached us, but that's beside the point). Anyway, everyone's watching waiting to see this amazing new thing when it appears ... and it burns ev

  • The ORI are coming and need the black hole to power the super gate.
  • Our supermassive black hole is quiescent right now, more or less, because it's not feeding. But there are a number of events that can dump gas into it. Collisions are the best way, but we're not colliding with anything right now massive enough to do the deed. However, I have read that there is a large repository of gas not too far from the BH that could fall in sometime in the next 30 million years or so. Not too much to worry about now, but it could fire things up a bit. However, our BH isn't terribly mas

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