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Hundreds of Black Holes Roam Loose In Milky Way

Posted by samzenpus on Thu Apr 30, 2009 05:01 AM
from the Maximilian-and-old-bob dept.
sciencehabit writes "From Science: 'Astronomers suspect that hundreds of medium-sized black holes are roaming loose in the Milky Way. These rogues, according to a new study, are the orphaned central black holes of the many smaller galaxies that the Milky Way has swallowed over its billions of years of existence.'"
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  • Anything else we need to be worrying about?

    • Global warming, fundamentalist christian, jews, muslims, poisonous food additives,and a global echonomic collaps can be a good start. :D

    • by Nephrite (82592) on Thursday April 30 2009, @06:09AM (#27770573) Journal

      Looks like everyone has already forgot the LHC...

    • And the biggest risk that most of us face, getting hit by a car on the way to work.

      • by Opportunist (166417) on Thursday April 30 2009, @06:52AM (#27770829)

        That's what has puzzled me to no end since the onset of various hypes. SARS? Your chance to catch it? Play the lottery if you do, your chance for a jackpot is higher. Mad cow? Ditto. Terrorism? 3000 affected of roughly 200 million (directly, not due to the political fallout). Swine/bird flu?

        And now compare that to the chance of a heart attack. Lung cancer. Getting run over by a car. Getting mugged. And various freak accidents that happen all the time.

        It's a miracle that you're still alive! And it's not because of black holes, not because of terrorism, not because of pandemics. It's because you're living.

        Your alternative is to spend your life under your bed. But then again, where's the difference to being dead already?

        • Re: (Score:3, Insightful)

          by Anonymous Coward

          It's not that. The government and it's agencies MUST overreact to these things, or at least hype the media up to let them know they are doing "everything they can" in light of the unfortunate turn of events Katrina caused. Because we didn't overreact at that time, a sh**load of angry black people came out of the woodwork looking for a FEMA handout because Kanye announced Bush hates black people. Now don't flame the comment as racist, it's not, but it was a very dynamic situation that people capitalized o

        • > Your alternative is to spend your life under your bed. But then
          > again, where's the difference to being dead already?

          I am not going to spend my life under my bed. That's where the monsters live.

        • Your alternative is to spend your life under your bed. But then again, where's the difference to being dead already?

          About six feet. *Rimshot!*

          • Re: (Score:3, Interesting)

            ... add up ALL the various possible dangers, and the odds of it happening in a given year...odds of getting hit by lighting, 1:22 million. Odds of being in a car accident 1:50,000, etc, etc...I suspect that once you compiled a comprehensive list, you'd end up being nearly certain you'll die in the next year.

            A few years back, I read an interesting article whose authors pretty much did just that, and wrote about the conclusions. One of their more interesting ways of expressing the results of the study was:

      • Well, I would like to know, if a black hole comes by, does it actually pull a whole planet into its hole, do we know if this is possible...

        If it has sufficient gravity, then yes, it is quite capable of "swallowing" a planet. Any black hole that formed in the "usual way" from a collapsing star, certainly has enough gravity (pretty much exactly the same as the star that it was before it collapsed) to suck in a nearby planet if the planet is unfortunate enough to be nearby. Of course, that's only really a problem with these "wandering" black holes - if our sun was mystically replaced with an equally massive black hole (which would be MUCH smaller in size), then the planets would continue to go around it exactly as they do now (although we'd all die from freezing since the hole isn't putting out heat like our sun does, but that's another matter entirely)

        I mean at the core a small start implodes and turns into a black hole, but does it have enough strength to suck in another star, or even a whole solar system...

        Again, depends on the size (gravity) of the hole, but generally yes - put two stars on a collision course and it'll be pretty nasty.

        and what happens if you put 2 black holes side by side, do they cancel each other out...sort of like putting a bag of holding inside a bag of holding...?

        Nope, they'd just "merge" in to one bigger one. So, two that had a mass of x, would become a single one with a mass of 2x.

        Black holes are pretty weird and there's a lot of strange physics around them when you get deep in to it, but at the very basic level, they're not particularly odd at all - just think of them as objects with a REALLY large mass for their size (but still no larger than many other objects around, such as stars (of course, holes that used to be galactic centres are generally a bit bigger, since our best theories regarding black hole galactic centres involve a LOT of matter going in to creating them)).

      • by jc42 (318812) on Thursday April 30 2009, @02:45PM (#27777617) Homepage Journal

        A couple of years ago, there was an astronomy news story about the discovery that our nearest spiral-galaxy neighbor, the Andromeda Galaxy, has two large black holes (with masses of several million sols) in its core. This explained some of the anomalies in that galaxy's shape, which isn't quite as flat or symmetrical as you'd expect a big spiral to be. The suggested explanation is a merger with another galaxy that probably happened several billion years ago, long enough that the resulting mess has settled down into what at first glance looks like a single normal spiral galaxy.

        This isn't at all unusual, though. There are lots of galactic collisions visible in space. There was a fun one a few days ago on the Astronomy Picture of the Day [nasa.gov] site. Stories on them generally explain that few if any of the stars collide, because they're too far apart. The dust and gas clouds do collide, and the result is a period of star formation. In many cases, simulations show that the galaxies merge, typically producing an elliptical galaxy if both were large and had different orientations. In the Andromeda case, they were probably roughly coplanar, so the merger just produced a slightly bigger spiral.

        Another recent story is about calculations showing that the Andromeda and Milky Way galaxies are on a collision course, and will collide in several billion years. The result may look a lot like the above picture to astronomers in other nearby galaxies.

        Astronomers have also found the remnants of several smaller galaxies that our Milky Way has gobbled up. They were generally disrupted, but most of the stars from a single such galaxy now have similar orbits, so each appears as a loose "stream" of stars with a thickening that corresponds to the core of the original small galaxy. It's likely that each such smaller galaxy contributed one or more "medium" black holes (with a few thousand solar masses) to our galaxy.

        Anyway, this story isn't especially surprising to anyone who follows atronomy news.

  • by Dutchmaan (442553) on Thursday April 30 2009, @05:07AM (#27770225) Homepage
    Perhaps all our money really WAS disappearing through a black hole!
  • I wonder if black holes could account for either of these things? Gamma rays would be released if a large mass hits a black hole. A cosmic ray could be accelerated if it passes too close to a black hole.
  • by Anonymous Coward on Thursday April 30 2009, @05:08AM (#27770237)
    My kind of galaxy!
  • Nah, I call BS (Score:4, Interesting)

    by DavidRawling (864446) <hulk_@NOsPam.yahoo.com> on Thursday April 30 2009, @05:13AM (#27770269)
    Scenario. The Milky Way swallows a galaxy, and by extension, all the stars around the central black hole. Yet, the same gravity that causes the stars to amalgamate completely misses the biggest mass in that swallowed galaxy? Why would that make sense?
    • Re:Nah, I call BS (Score:5, Interesting)

      by MichaelSmith (789609) on Thursday April 30 2009, @05:22AM (#27770327) Homepage Journal

      Scenario. The Milky Way swallows a galaxy, and by extension, all the stars around the central black hole. Yet, the same gravity that causes the stars to amalgamate completely misses the biggest mass in that swallowed galaxy? Why would that make sense?

      The only bit which I think is strange is that the black hole from the swallowed galaxy hangs around in our galaxy. It should have enough velocity to pass right through our galaxy and never come back. Most likely the captured stars would die of old age before they passed though our galaxy. Only red dwarfs would keep going because of their long life. Gas clouds in the captured galaxy would interact with our gas clouds. I think that is the only component which would really get captured.

      • What makes you think the black hole would have a trajectory any different from any of the stars from the captured galaxy? Because it's marginally heavier than the other stars?
      • Re: (Score:2, Informative)

        since the gravitation force is ~M_blackhole*M_milkyway and F_bh=m_bh*a i dont think the trajectorie is dependent on the mass of the particle in the first order as long as m_bhm_milkyway
    • Re:Nah, I call BS (Score:4, Interesting)

      by Brown (36659) on Thursday April 30 2009, @05:24AM (#27770333) Homepage
      The Milky Way swallows a galaxy, and the swallowed galaxy's stars get added to the milky way, orbiting the galactic centre in the usual way. Presumably the same happens to the black hole - there's no reason why it should be sucked into the middle. Black holes will happily orbit around each other, as long as they're outside each other's event horizons.
      • Re:Nah, I call BS (Score:4, Interesting)

        by stonewallred (1465497) on Thursday April 30 2009, @06:29AM (#27770699)
        What happens when two black holes actually intersect at their event horizons? Inquiring non-astrophysicists would like to know.
        • Re:Nah, I call BS (Score:5, Informative)

          by beanyk (230597) on Thursday April 30 2009, @07:12AM (#27770983)

          What happens when two black holes actually intersect at their event horizons? Inquiring non-astrophysicists would like to know.

          They merge into one bigger hole. The final hole mass will be (almost) the sum of the two masses, and will likely have a significant spin, even if the pre-merger holes don't.

          Disclaimer: this is actually my area of research.

            • Re:Nah, I call BS (Score:4, Interesting)

              by beanyk (230597) on Thursday April 30 2009, @07:40AM (#27771229)

              Well for one thing, the "time moving slowly" thing is an observer-dependent effect. If you were the one falling into the hole, you wouldn't notice any real time lag at all [depending on the size of the hole -- and your personal oxygen supply, etc -- you might even survive crossing the horizon].

              But to a distant observer, your progress would look more and more gradual. Signals leaving you would also get more and more red-shifted, and eventually pass out of the visible spectrum. So a distant observer would never see you cross the horizon.

        • Re:Nah, I call BS (Score:5, Interesting)

          by AlecC (512609) <aleccawley@gmail.com> on Thursday April 30 2009, @06:03AM (#27770539) Homepage

          Because the galaxy is not a point mass. Most ordinary star/planet modelling is based on viewing each object as a sphere, which behaves as a point mass at the centre. But when you penetrate inside another body, as two galaxies do when they collide, this simplification no longer applies. Some of the mass of the "other" galaxy moves behind the penetrating galaxy, slowing it down rather than, as the point mass model would suggest, continuing to accelerate into the centre. In the simplest model, of inter-penetrating spheres, gravity no longer has an inverse square law but an inverse linear law. Of course, galaxies are not uniform spheres, and the modelling is much harder. However, it is widely accepted that when two galaxies collide, they merge and the vast majority of the mass forms a single galaxy - though clusters may be flung out. If the galaxies are of broadly similar masses, the distinctive spiral structure is wiped out and the merged result becomes an elliptical galaxy for a few hundred million years before the spiral structure re-establishes.

          Google "andromeda collisions" for simulations of the collision between our galaxy and the Andromeda galaxy in about 3 billion years.

          • But when you penetrate inside another body

            There aren't too many slashdotters that can relate to your analogy. May I suggest a car one instead? ;)

          • Re: (Score:3, Interesting)

            Why would the stars and black hole change their trajectory significantly?

            Gravity?

            Gravity can change the direction of travel of a black hole or star. It can't significantly change momentum unless the object passes very close to a large mass. Our space probes do that at Jupiter, etc, but that requires guidance or an extreme amount of luck. To be captured by gravitational slingshot a black hole would have to pass very close to our own central black hole. Thats not very likely.

  • Milky Way? (Score:5, Funny)

    by krou (1027572) on Thursday April 30 2009, @05:21AM (#27770313)

    If I found hundreds of "black holes" in my "Milky Way", surely that would mean it's an Aero?

    I'll grab my coat ...

  • and it sounded like a cartoon.
  • by VShael (62735) on Thursday April 30 2009, @05:45AM (#27770441)

    And how can the news networks use it to induce fear?
    And more importantly, how we can we use it to sell stuff?

    "Black hole protective face-masks" just don't seem like a seller, to me.

    • The Black Holes were created by the Large Hadron Collider during the short time that it was online, before the radioactive liquid helium leaked out and freeze-burned its way down toward the center of the earth (China Syndrome), where it was reflected back up and surfaced in a pig patch in Mexico, and irradiated sick pigs with Swine Flu, which mutated into the Mexico Flu, and hopped a ride on some poor little kid, who passed it on to Mexico city.

      Seems all pretty plausible to me.

  • by hack slash (1064002) on Thursday April 30 2009, @06:15AM (#27770611)
    Take this wise lesson from Red Dwarf:

    "Well, the thing about a Black Hole, its main distinguishing feature, is it's black. And the thing about space, your basic space colour is black. So how are you supposed to see them?"

    *later on*

    "They weren't Black Holes."
    "What were they?"
    "Grit. Five specks of grit on the scanner-scope. See, the thing about grit is, it's black, and the thing about scanner-scopes..."
    "Oh shut up!"
    • I vote for Buck Rogers to be remade like BSG, who's with me?

      A few years ago, I watched a cheesy rerun with Wilma posing as a hooker to sneak into some fat-cat's hotel room. Oh my! She was SMOKIN' back in the day! I just never picked up on that as a kid.

  • by hyades1 (1149581) <hyades1@hotmail.com> on Thursday April 30 2009, @07:09AM (#27770961)

    I'm reasonably sure there's one in my ex's purse. Money goes there to die.

  • by jollyreaper (513215) on Thursday April 30 2009, @08:23AM (#27771691)

    For the love of Christ, Republicans! You know that line about anti-zombie research? Don't fucking touch it! You saw what happened when you cut funding for volcano and pandemic flu research!