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Space Science

Milky Way's Black Hole a Gamma Source? 100

Posted by kdawson
from the high-energy-pinball dept.
eldavojohn writes "A paper recently accepted for publication (preprint here) proposes a sound explanation for the source of the gamma rays that permeate our galaxy. The Milky Way's central object Sagittarius A*, widely believed to be a supermassive black hole, is now suspected to be the source. To test this theory, two scientists created a computer model to track the protons, flung outward with energies up to 100 TeV by the intense magnetic fields near the event horizon, as they make a random walk through the plasma environment. It can take thousands of years for them to travel 10 light-years from the black hole, where they collide with lower-energy protons to form pions. These decay into gamma radiation emanating from a torus-shaped region around the central object."
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Milky Way's Black Hole a Gamma Source?

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  • Hulk!
  • by Archangel Michael (180766) on Tuesday March 06, 2007 @04:59PM (#18254724) Journal
    "The Milky Way's central object Sagittarius A* [CC], widely believed to be a supermassive black hole, is now suspected to be the source."

    Would that make it an "A-Hole" ?????
  • Zodiac? (Score:1, Offtopic)

    by zoloto (586738)
    I always knew I was more powerful because of my astrological sign. Now I have proof!
    Or proof that my life sucks... either way, it's something!
    • by kan0r (805166)
      Interesting. It is something, good or bad doesn't matter really. All that matters is that there is a connection somehow. This actually seems to be enough to satisfy something in here, something that is bored a bit. I am of the same astrological sign, by the way.
  • Black Hole (Score:2, Funny)

    by alexj33 (968322)
    The Milky Way's central object Sagittarius A*, widely believed to be a supermassive black hole, is now suspected to be the source.

    That black hole must really suck.
  • by sqlrob (173498) on Tuesday March 06, 2007 @05:02PM (#18254764)
    Long Shot is ready for departure
    • Re: (Score:2, Funny)

      God, how I love the concept of the "Long Shot". 75 seconds to the light-year [-swoon-].

      Imagine a Beowulf Shaeffer cluster of those...

      Thanks folks, I'll be here all week. Be sure to tip your Puppeteer generously!
    • Get ready to recieve my Hot Needle of Inquiry.
    • by CRCulver (715279)
      The Larry Niven short story where the galactic core was explored was "At the Core" (now collected in Crashlander [amazon.com] ). That was a Beowulf Shaeffer story, not a Louis Wu one. And, of course, Niven's vision of the galactic core--just lots of densely packed stars--is superseded by the current speculation that it's a black hole.
      • by Agripa (139780)
        Niven's short story "Rammer" which later became the novel "A World Out of Time" featured a galactic sized black hole at the center of the milky way . Admittedly, this was 10 years after "At the Core".

  • huh? (Score:2, Interesting)

    I thought the background gamma radiation was from the big bang and thus older than the galaxies?
  • by PIPBoy3000 (619296) on Tuesday March 06, 2007 @05:07PM (#18254838)
    I wonder if that means that life is only possible near the outer arms of the galaxy? If you assume that gamma rays are a point source in the middle of our galaxy, what sort of radiation levels are you going to see closer to the center?
    • by Normal Dan (1053064) on Tuesday March 06, 2007 @05:28PM (#18255078)
      There are already dangerous levels of radiation within our own solar system, however, we are protected by an atmosphere. I would imagine one of two possibilities. Any planet with the potential for life closer to the center of our galaxy would have enough shielding of some sort (either a thick atmosphere or a thick ocean) to allow life to form on almost any suitable location in the galaxy. The other possibility is, life can exist in high amounts of radiation, but it might not be life as we know it.
      • by Dan Slotman (974474) on Tuesday March 06, 2007 @06:13PM (#18255582)
        Actually, other parts of the galaxy are farther from the milky way and other black holes. These arms, teeming with life, use gamma rays to communicate and travel. They haven't come calling since our arm is poisoned with radiation, making interstellar travel prohibitively dangerous!
      • Of course. Life evolves to fit the current conditions. In a high radiation environment, I can imagine a life form that takes advantage of the high radiation levels to rapidly mutate and evolve, increasing its chances of survival in a hazardous environment. Actually, there are plants on this very planet that for some reason have developed the abilty to mutate rapidly. The hawthorn for example. There was a point when there were hundreds of named species of hawthorn. Before the botanists realized the damned th
        • by Eddu (999813)
          You know that's nice, but what's their IQ? IMO it's highly improbable that intelligent races evolve in unstable or high radiation environments. High radiation destroys DNA and well - unstable environments just kill so fast that it's not better to have brains instead of a thick shell or high reproduction
          • by Magada (741361)
            We have some evidence that complex organisms evolve from colonies (most likely, simbyotic colonies) of simpler organisms. What if these hard-shelled, fast-breeding things work out a way to stick together and work as a whole?
          • Actually, it seems to me that intelligence would be likely to evolve more rapidly in a rapidly evolving biosystem. And once it arose, you'd have a much broader range of implimentations of that intelligence, including such specialized abilities as telepathy and telekinesis. Also, one would expect that there would be rapid evolution in such an environment of mechanisms that protected certain parts of the genetic material, either through redundancy or through dynamic reconfiguration.
      • Water Bears (Score:3, Informative)

        Tardigrades [aka Water Bears], which live everywhere on this planet Earth, can...
        1) resist storage in liquid nitrogen
        2) survive in contact with mineral acids, organic solvents, and boiling water
        3) survive in a a vacuum and under high pressure
        4) withstand ionizing radiation of over 600,000 roentgens (500 roentgens would be fatal to a human)
        • Re: (Score:3, Interesting)

          by khallow (566160)

          Hmmm, you got to wonder if that's a fortuitous coincidence or if that amazing ability to survive was spurred by something in their environment. Now that I think of it, any organism that can exist in an indefinite "cryptobiosis" [wikipedia.org] state (ie, when all metabolic processes stop for a possibly long period of time) would do better if it had some of the above properties. In particular, the ability to survive extreme genetic damage is necessary IMHO. Suppose humans had similar abilities. If I entered cryptobiosis say

        • by Dan Hayes (212400)
          Water bears really do rock - crazy tough little buggers! Fire a few into space, and they'd be ready to wake up whenever they hit water ;)
      • by Kyeetza (927172)

        .....The other possibility is, life can exist in high amounts of radiation, but it might not be life as we know it.
        I've always been curious about other kinds of life. With all the complexity that exists, it seems naive to think that DNA is the only kind of self replicating molecule in the universe......
        • by khallow (566160)
          Or that we're the only way that DNA-based life could evolve.
        • Re: (Score:3, Interesting)

          by Artifakt (700173)
          There are definitely at lest one other self replicating molecule already known (RNA). RNA however has a much higner rate of copying errors, and lower error rates actually promote selection (down to a minimum - obviously zero errors means no selection at all, but even DNA is somewhere still well above the calculated ideal error rate for fastest selection).
          This seems somewhat counter-intuitive, but if you think of a species as a set with somewhat fuzzy boundaries, more errors mean
      • by mdielmann (514750)

        There are already dangerous levels of radiation within our own solar system, however, we are protected by an atmosphere.

        No, we're protected by a magnetosphere. It deflects solar wind and, I'd assume, other charged particles that are sleeting our planet. Mars [nasa.gov] has no such magnetosphere (and not much of an atmosphere, either - not entirely unrelated), and radiation is a real problem there.

    • Re: (Score:2, Interesting)

      by MollyB (162595) *
      I'm no scientist, but as amateur astronomer and cosmology 'nut' I can say that even though the central portion (the "bulge") may have higher levels of radiation of all frequencies that would be damaging to life-as-we-know-it, the fact remains that out in the spiral arms of the galaxy there are many stellar nursuries (huge molecular clouds that occasionally have a shock wave pass through that can ignite new stars). These regions sometimes congeal a massive star which burns in a few millions of years rather t
    • by iago-vL (760581)
      Don't forget about Sha Ka Ree [wikipedia.org]. It's at the centre of our galaxy and the crew of the Enterprise seemed all right...
    • by jwiegley (520444)

      What??? We're not the center of the galaxy??? Somebody better tell God, 'cause he's gonna be pissed!!

  • oblig. (Score:3, Funny)

    by Rob T Firefly (844560) on Tuesday March 06, 2007 @05:08PM (#18254852) Homepage Journal
    What does God need with a starship?
  • Do we know? (Score:2, Interesting)

    by pygmy_jesus (1071948)
    I've been semi-interested in Cosmology/Astrophysics lately, and from everything I've seen and read so far, I've ascertained that we don't know much. Between dark matter, dark energy, gravity, black holes, big bang, etc. it seems like we just conveniently make up "stuff" to fit some model or equation. Do discoveries like this mean anything at this time considering there's no way to prove any of it?
    • Re: (Score:2, Funny)

      by IflyRC (956454)
      Between dark matter, dark energy, gravity, black holes, big bang, etc. it seems like we just conveniently make up "stuff" to fit some model or equation.

      Is that not the same statement many have made as to the reason man in early history believed in gods?

      That black hole is angry, its throwing things at us!
    • Re:Do we know? (Score:5, Insightful)

      by MightyMartian (840721) on Tuesday March 06, 2007 @05:20PM (#18254984) Journal

      I've been semi-interested in Cosmology/Astrophysics lately, and from everything I've seen and read so far, I've ascertained that we don't know much. Between dark matter, dark energy, gravity, black holes, big bang, etc. it seems like we just conveniently make up "stuff" to fit some model or equation. Do discoveries like this mean anything at this time considering there's no way to prove any of it?
      Translation: I know the names of some scientific fields, but never read more than the science headlines in the newspaper. Clearly this is the fault of scientists.
      • Re:Do we know? (Score:4, Insightful)

        by Ibag (101144) on Tuesday March 06, 2007 @06:28PM (#18255776)
        While this probably is an accurate translation, GP has a point. A lot of science can seem rather ad hoc at times. Before we had discovered all the planets, scientists noted that the orbits of the known planets were not quite what they should be. Instead of declare that newton's theory of gravity was wrong, they theorized that there was an unknown planet. After doing some calculations, they determined where this planet had to be, looked up at the sky, and found Neptune.

        Similarly, when cosmologists look at the apparent rate of expansion of the universe (and how that rate has changed over time), they get that if their model of the way things work (general relativity) is correct, then their estimates of the mass in the universe based on empirical observation cannot possibly be right. Instead of abandoning relativity and leaving a void in its place, they say, "This will work of there is a large amount of matter that we can't observe. Dark matter!" Of course, this doesn't resolve everything, and we need various other adjustments (like dark energy, or physical constants that aren't constant) which look like kludges, but which have predictive power and are the best answers we've got.

        Do we "know" this is correct? Of course not! We don't even know that the next time we drop an apple, it will fall to the floor. Science is a process, though, and it isn't productive to dismiss the theories of today before we've seen the observations of tomorrow.
        • by rlazarus (1002774)

          It doesn't always work that way, though. A couple of thousand years before Neptune was discovered, there was a similar problem. At that point, science figured that all orbits were circular - it was simple, it was clean, but the problem was, it didn't quite fit the observations. So the answer was epicycles [wikipedia.org]: the planets still moved in circular orbits, but there were smaller loops tacked on, to make everything come out right.

          It fit the data reasonably well, but let's face it - it was kind of silly. Okay,

          • Re: (Score:3, Insightful)

            by Ibag (101144)
            Well, I think that there is an important way in which this is nothing like epicycles. With the theory of epicycles, people (I hesitate to call them scientists) were looking to describe how the heavens moved without much thought of why. Here, scientists are working with a theory of why the world behaves as it does, and is trying to tweak parameters to make the model obey observation. When people added circles within circles to make the epicycles more accurate, there was no reasonable explanation for why t
        • Re: (Score:3, Interesting)

          by MightyMartian (840721)
          I think the rate of expansion is an awfully good example. The standard inflationary model does have a problem in that it doesn't predict the expansion rate we see. Scientists have two choices when the data and the model don't jive. They can either toss the model and start from scratch, or attempt to alter the model to reflect observations. The decision to do either is one based upon how well other predictions of the model perform. In the case of the inflationary model, other aspects of the theory do ex
    • Same here (Score:3, Insightful)

      by quokkapox (847798)

      I've been semi-interested in Computer Science/Mathematics lately, and from everything I've seen and read so far, I've ascertained that we don't know much. Between dark fiber, optimal algorithms, P=NP, O(n log n) (and other equations like that), cryptography, etc. it seems like we just conveniently make up "stuff" to fit some model or equation. Do discoveries like this mean anything at this time considering there's no way to prove any of it?

      [No offense intended--just pointing out that a lack of sophistic

    • By any chance, do you edit Wikipedia?
    • Re:Do we know? (Score:4, Informative)

      by Fujisawa Sensei (207127) on Tuesday March 06, 2007 @07:14PM (#18256332) Journal

      We know a lot more than you give us credit for, perhaps you need to read a little deeper, try Relativity by Albert Einstein. AE just made up stuff because observations didn't fit Newtons proven model. So he just made up some equations to match the observations. But alas his made up equations didn't correctly model acceleration or gravity, so he made up GR.

      GR is a very accurate theory, and there is experimental evidence of it. The two most famous are the perihelion precession of Mercury, and stars visible near the eclipsed sun. Of course being semi-interested in Cosmology/Astrophysics you would already know that.

      Stuff like Dark Matter that just doesn't get made up, it falls out naturally when equations which are shown to work in one situation are shown to fail in another. DM vs GR for example. There's a lot of guess work as to what DM is, but that's where life gets interesting, we don't know what it is. We know 'something' is there, we just don't know what the something is. DM isn't a convenience item, its a wart, because without the wart GR which is shown to work in other cases could be used to correctly model galactic motion.

    • Re:Do we know? (Score:5, Insightful)

      by ChrisA90278 (905188) on Tuesday March 06, 2007 @07:27PM (#18256524)
      "Do discoveries like this mean anything at this time considering there's no way to prove any of it?"

      There is no way in science to PROVE ANYTHING. All one can do is disprove a theory you can never prove a theory to be true. This is a very basic part of how science works

      A theory is a good theory if it is predictive and makes good predictions and it is disprovable and it has not been disproved. But a theory can't be proven to be true.

      Have you ever read Wittgenstein? Goggle the name. He wrote, long before the 1960's a question "Have I ever been to the moon?" He argued that while he thought he'd never been there and knew of no one who had he could not prove he's never been to the moon and further that such proof was impossible. Proof is very different from being very, very certain. He goes on to explain the difference and what can and can not be proven. Some things can never be proven not matter what you do

      In science all you can be is "very certain" but must always be open to being proven wrong. For example we think and are very certain that light follows the inverse square law but can you prove that it ALWAYS does? It only takes one exception to disprove the theory but a trillion observations would not prove it true.
    • pygmy jesus-I am likewise able to see that mainstream astronomers make stuff up. Instead of revising theories, or beter yet, throwing discredited theories out, the bigbangers add layers of gobblygook to their gravity-only paradigm. The electric force is 10 to the 39th power stronger than gravity. Go to www.thunderbolts.info to learn all about a cosmology theory that makes sense AND backs it up with facts, experiments, predictions that actually come true, and much more! Larry
  • Is this the object at the center of the galaxy? A while back someone posted a link to video of a star orbiting the center of our galaxy. It had a period of about 10 (11 or 12?) years and a closest approach to the black hole at a distance similar to the orbital radius of pluto. Since this star is observable and much closer to the black hole than 10 light years, it seem improbable that photons take a "random walk" out to a distance of 10 light years. That would make said star unobservable - wouldn't its light
    • by Bandman (86149)
      I would think that unless it rotated against the galactic plane, it would be rendered invisible half of the time it was on the far side of SgsA*
    • Re: (Score:2, Informative)

      by btgreat (895041)
      The article was talking about protons, not photons. I'm not exactly sure whether or not the motion is random, but it certainly shouldnt have any effect on whether the PHOTONS of the star are visible or not..
      • Re: (Score:3, Funny)

        by gr8_phk (621180)
        Sorry. My dumb. I read too fast and saw all this stuff about gama radiation and my brain converted protons into photons. Hey, there you have it - proton decay due to dim gray matter - er uh dark matter.
  • by eno2001 (527078) on Tuesday March 06, 2007 @05:31PM (#18255110) Homepage Journal
    It's time to cue the Goatse jokes and links! Let's give 'em hell boys!
  • Incorrect summary (Score:5, Interesting)

    by forand (530402) on Tuesday March 06, 2007 @05:54PM (#18255396) Homepage
    The summary makes it sound as though this is an explanation for the DIFFUSE gamma-ray emission seen in our Galaxy. This is not the case, the paper only discuss a source of gamma-rays observed to be spatially coincident with the Galactic center. Gamma-ray telescopes do not have high angular resolution so there is a possibility that the gamma-rays are not actually coming from the Galactic center in the first place. Finally this is not a new proposal. Proton acceleration near black holes is quite commonly discussed and accepted. Furthermore photo-pion production is a well known process that has been well measured in the lab. I think the real meat of this paper is that they are suggesting observations of emission associated with the black hole that we have observed gravitationally for a while now. This is the big news, not that the gamma-rays in our galaxy have been explained, not that protons make pions which decay into gamma-rays.
  • Pinball on a Galactic Scale By Phil Berardelli ScienceNOW Daily News 28 February 2007 The center of our Milky Way galaxy crackles with lethal gamma-rays, emitting trillions of electron volts of energy. Yet most astrophysicists consider our corner of the universe a relatively placid place, so the source of all this energy has remained mysterious. Now, members of an international team think they have found the answer: high-energy protons ejected by the supermassive black hole that lies at the heart of the ga
    • by Anonymous Coward
      Pinball on a Galactic Scale

      By Phil Berardelli
      ScienceNOW Daily News
      28 February 2007

      The center of our Milky Way galaxy crackles with lethal gamma-rays, emitting trillions of electron volts of energy. Yet most astrophysicists consider our corner of the universe a relatively placid place, so the source of all this energy has remained mysterious. Now, members of an international team think they have found the answer: high-energy protons ejected by the supermassive black hole that lies at the heart of the galaxy.
  • by mrtexe (1032978) *
    Over twenty years ago, physicist Paul LaViolette [etheric.com] stated that gamma rays emanate from the center of the galaxy. (See prediction 12 at the link)
  • the protons, flung outward with energies up to 100 TeV by the intense magnetic fields near the event horizon, as they make a random walk through the plasma environment. It can take thousands of years for them to travel 10 light-years from the black hole, where they collide with lower-energy protons to form pions. These decay into gamma radiation emanating from a torus-shaped region around the central object.

    Or so it appears, according to the subatomic particles God set in motion "already on their way", when

  • so what im gathering is that black holes take in everything (time/space/light..etc) but emit gamma rays??????
    • Re: (Score:1, Informative)

      by Anonymous Coward
      No, they still don't emit anything (except Hawking radiation, and that's kind of complicated). These gamma rays are from protons getting close to the event horizon, but then getting shot away at incredibly high energies due to interactions with the massive magnetic fields in the area. They then smack into other particles, releasing a shower of sub-particles and gamme rays.
  • by Khyber (864651)
    In Soviet Korea.....

    http://ftw.generation.no/img/sovietkorea.jpg [generation.no]
    • Mod parent down, the link is to Goatse.
      • by Khyber (864651)
        Screw you, generations got majorly hotlinked last night. It's supposed to be a bunch of Korean soldiers all in the middle of a high-jumping exercise. All I did was give a link to the image.

        Not my fault some other asshole decides to hotlink the damned image and ruin this post for everyone else.

        And *THIS* is why Slashdot needs the ability to edit posts, so we can kinda catch ourselves if things like this happen and correct it before it gets too overly-fucked.

        So, for those who modded me down, yea, you're right
  • I can see how this would work. If my desktop gets too dark and I can't see things properly, I adjust the gamma.
    Even I winced at that one.

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