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Space News

New Galactic Neighbor 200

Posted by samzenpus from the there-goes-the-neighborhood dept.
Dan Yocum writes "The Sloan Digital Sky Survey reveals a new Milky Way neighbor: a galaxy so big we couldn't see it before. A huge but very faint structure, containing hundreds of thousands of stars spread over an area nearly 5,000 times the size of a full moon, has been discovered and mapped by astronomers of the Sloan Digital Sky Survey."
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New Galactic Neighbor More

New Galactic Neighbor

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  • So (Score:5, Funny)

    by Mikkeles ( 698461 ) on Wednesday January 11, 2006 @09:57PM (#14450834)
    Can't see the galaxy for the stars, eh?

  • How do they define a galaxy? (Score:3, Interesting)

    by keraneuology ( 760918 ) on Wednesday January 11, 2006 @10:03PM (#14450867) Journal
    What makes this a galaxy rather than just some random swirl in the cosmos? (TFA doesn't really say)... does this galaxy have a black hole to call its own in the middle? What happens if a black hole eats another black hole?

    • Re:How do they define a galaxy? (Score:5, Funny)

      by Travoltus ( 110240 ) on Wednesday January 11, 2006 @10:07PM (#14450880) Journal
      "What happens if a black hole eats another black hole?"

      It becomes Congress?

    • What happens if a black hole eats...? (Score:5, Funny)

      by fredistheking ( 464407 ) on Wednesday January 11, 2006 @10:08PM (#14450887)
      Try to imagine all life as you know it stopping instantaneously and every molecule in your body exploding at the speed of light.
    • >What makes this a galaxy rather than just some random swirl in the cosmos?

      it's a strucured group of stars. our galaxy is very roughly a flat disk of stars, this new one is a sphere of stars intersecting it.

    • Re:How do they define a galaxy? (Score:5, Insightful)

      by FalconZero ( 607567 ) * <FalconZero&Gmail,com> on Wednesday January 11, 2006 @10:15PM (#14450935)
      What makes this a galaxy rather than just some random swirl in the cosmos?
      If I remember my Physics elective from uni, Galaxies are internally gravitationally bounded, that is the entire 'clump' of things is held rougly in equalibrium with gravity providing the contracting forces.
      does this galaxy have a black hole to call its own in the middle?
      The jury is out on the existance of supermassive holes at all galactic centers (partly due to obvious impossibility of direct detection).
      What happens if a black hole eats another black hole?
      Black hole collisions are theoretically possible, and has been simulated on a Cray [uiuc.edu] (pretty pictures included).

      • Re:How do they define a galaxy? (Score:5, Interesting)

        by waytoomuchcoffee ( 263275 ) on Wednesday January 11, 2006 @11:26PM (#14451287)
        Black hole collisions are theoretically possible, and has been simulated on a Cray

        Yes, this is offtopic, but what is really wild is that they simulated that in 1994 on a Cray C90, which has a floating point speed of 16 gigaflops. Back here in 2006: the Playstation 3, a TOY, has a floating point speed of 2 teraflops.

      • The jury is out on the existance of supermassive holes at all galactic centers (partly due to obvious impossibility of direct detection).

        I disagree. The orbits of stars that get very close (while moving very fast!) to our galaxy's central mass have been directly observed, as shown on this page [wolaver.org], which includes an amazing movie of stars whipping around the central mass. Likewise, we have observed strong x-ray variability of that region on a time scale of hours, implying a source no larger in size a few li

        • The previous poster was pointing out we don't know if there's a black hole at the center of ALL galaxies. As you point out, there's ample evidence of a black hole at the center of our galaxy, but that doesn't mean there's one in the center of every other galaxy.
        • I should point out that all the methods you've suggested for detection are indirect detection. A fundimental property of a black hole (as we understand it) is that everything beyond its event horizon is never emitted. Correct me if I'm wrong, but the only thing that is directly emitted from a black hole is Hawking radiation (which is so weak as to make its detection practically impossible. Since we can't detect anything it emits we can't directly detect it. We can however infer it's presence from its intera
          • A fundimental property of a black hole (as we understand it) is that everything beyond its event horizon is never emitted.

            Correct, except this in itself provides a means to differentiate a black hole from something with a surface in the case where the black hole has a companion star. Material from the companion is pulled towards the black hole. If there were a surface the material hits the surface and releases a burst of X-rays periodically. A black hole will never have these burst since it does not have
      • If I remember my Physics elective from uni, Galaxies are internally gravitationally bounded, that is the entire 'clump' of things is held rougly in equalibrium with gravity providing the contracting forces.

        Because if it wasn't bound by gravity it would be an open cluster nebula.

        what really matters though is isf this cluster has 100 billion stars or not. if it only has 99,999,999,999 stars it's not a galazy at all. I assume someone counted before declaring this collection of distant stars a galaxy, but some

      • If I remember my Physics elective from uni, Galaxies are internally gravitationally bounded, that is the entire 'clump' of things is held rougly in equalibrium with gravity providing the contracting forces.

        Our solar system is rougly in equilibrium... it isn't a galaxy. Lots of binary or trinary star systems are also in equilibrium - not galaxies either.

        Not to be difficult, but galaxies have -lots- of smaller clumps of stuff in gravitational equilibrium and they are all subsets of, yet still part of, t

  • Not very long ago... (Score:5, Funny)

    by ian_mackereth ( 889101 ) on Wednesday January 11, 2006 @10:10PM (#14450898) Journal

    ... in a galaxy surprisingly not so far away...

  • Galaxy?! (Score:2, Funny)

    by faqmaster ( 172770 )
    And it's headed this way!!!!!!!

    • Re:Galaxy?! (Score:4, Interesting)

      by SlowMovingTarget ( 550823 ) on Thursday January 12, 2006 @01:11AM (#14451759) Homepage

      Actually, on an intergalactic scale, this thing is freakishly close. According to TFA this dwarf galaxy is 30,000 light years from Earth. The distance from Earth to the center of the Milky Way galaxy is roughly 27,700 light years (according to Wikipedia [wikipedia.org]). This thing is nearly right on top of us.

      BTW, if you're preparing to shoot it, the quote you're looking for is "It's coming right for us!"

  • Could this be... (Score:5, Interesting)

    by idonthack ( 883680 ) on Wednesday January 11, 2006 @10:15PM (#14450932)
    Could this be what's warping the Milky Way [slashdot.org], previously thought to be Dark Matter?

    • Re:Could this be... (Score:4, Informative)

      by Razor Sex ( 561796 ) on Wednesday January 11, 2006 @11:37PM (#14451336)
      Yes and No. Part of it, perhaps. But all large scale structures have masses far greater than that of their visible matter content. Spiral galaxies typically have a dark matter to light matter ratio of 10:1, ellipsoidal galaxies 7:1, superclusters 100:1, and so on.

  • *in warbly voice* (Score:4, Funny)

    by phaetonic ( 621542 ) on Wednesday January 11, 2006 @10:17PM (#14450943)
    It's a trap!!!!

  • Dwarf galaxy (Score:3, Insightful)

    by Chess_the_cat ( 653159 ) on Wednesday January 11, 2006 @10:17PM (#14450949) Homepage
    "a galaxy so big we couldn't see it before"

    It's a "dwarf galaxy" and yet so big we couldn't see it before?

    • By definition, "dwarf" really refers to its mass / luminosity content, I think.

      I don't really pay attention to these guys and type of work, so I could be wrong.

    • Re:Dwarf galaxy (Score:5, Informative)

      by techno-vampire ( 666512 ) on Wednesday January 11, 2006 @10:37PM (#14451049) Homepage
      It's a "dwarf galaxy" and yet so big we couldn't see it before?

      That's right. It's a dwarf galaxy because its actual size is small (compared to other galaxies) but its apparent size is 5,000 times that of the Full Moon because it's so close, as galaxies go.

      In case that's not enough to explain it to you, consider that the Moon is much smaller than Jupiter, but appears to be larger because it's much nearer.

    • a galaxy so big we couldn't see it before

      Shouldn't that be

      a galaxy so close we couldn't see it before.

    • May I refer you to Father Ted [imdb.com]:

      Father Ted: Now concentrate this time, Dougal. These
      [he points to some plastic cows on the table]
      Father Ted: are very small; those
      [pointing at some cows out of the window]
      Father Ted: are far away...

  • Futurama-o-rama (Score:2, Offtopic)

    by radiotyler ( 819474 )
    Leela: I don't know what you did, Fry, but now all the planets in the galaxy are gonna be crackin' wise about our Mommas...
    Hermes: I'm just glad my fat ugly Mama isn't around to see 'dis day...
    Professor: Enough about your promiscious mother, Hermes...

  • 5000 times the size of a full moon? (Score:4, Informative)

    by qualico ( 731143 ) <worldcouchsurferNO@SPAMgmail.com> on Wednesday January 11, 2006 @10:21PM (#14450974) Journal
    "spread over an area nearly 5,000 times the size of a full moon,"

    Interesting wording.
    So that must mean 5000 full moons in the sky?

    Moon = 1800 arc seconds
    or 1800/60 = 30 arc minutes.
    or 30/60 = .5 degree

    So what is that in degree of sky?
    A fist at arms length is roughly 10 degrees.
    • Roughly sqrt(5000) ~ sqrt(4900) = sqrt(7*7*10*10)= 70.

      So, if the diameter of the moon is about 0.5deg, this thing is about 70 x 0.5 = 35 deg in diameter (if circular, but mind you, the original article says it is not).

      That's huge.
      • I find it amazing that you actually factored the square root, rather than reaching for a calculator. You are, of course, right on; sqrt(5000) == 70.711 to five digits (which is probably about three more than are called for given a phrase like "about five thousand")

    • Re:5000 times the size of a full moon? (Score:5, Funny)

      by Quixote ( 154172 ) * on Wednesday January 11, 2006 @10:34PM (#14451034) Homepage Journal
      Moon = .5 degree
      FTFA: nearly 5,000 times the size of a full moon

      So naturally it is 5000*0.5 = 2500 degrees, silly!

      .

      .

      .

      ;-) for the ;-) -impaired
      • Just a guess mind you, but since the area is about 5,000 full moons, you just might suspect the width of the object was about 80 full moons, assuming of course the area is approximately circular. That would make it about 40 degrees across.

    • Re:5000 times the size of a full moon? (Score:5, Informative)

      by Edmund Blackadder ( 559735 ) on Wednesday January 11, 2006 @10:35PM (#14451042)
      Well they said the area was 5000 times the size of a full moon. I.e. they are comparing the two dimensional visible area of the galaxy with that of the moon.

      The measurements you offered for the degrees of the moon concerns of course only one dimesnion of the moon.

      Now, suppose we assume that that galaxy is roughly squarish, we just need to take the square root of 5000 and we get roughly 70 which means that in the sky the galaxy is 70 times bigger than the moon in any one dimension (lets say width).

      Therefore, assuming your other calculations are correct, then the galaxy is about 70x0.5= 35 degrees in the sky. Which is pretty big if you think about it.

      • Now, suppose we assume that that galaxy is roughly squarish

        Ah, that reminds me of one of my favorite jokes:

        The owner of a large dairy wants to increase the efficiency of his business, so he goes to the local university for some ideas. Unfortunately all of the biologists and engineers are busy, but he does run into a professor of physics, who impresses him with his great intelligence. The physicist agrees to help, saying "I vill get to vork on it at vonce!"*

        After a few weeks pass the dairyman gets a

      • Now, imagine if that was a full-sized galaxy, and we could see what it really looks like! It's a pity we didn't develop in a dwarf galaxy, with a nice big spiral galaxy filling half the night sky - that'd be sweet!

        --LWM

  • Star Question (Score:2, Interesting)

    by dkdeath1 ( 594079 )
    I am not well versed in astronomy in general, but how could it be so faint we havent noticed it yet? Isint there a certain level of luminosity that is required to be a star? Could there possible be something between us and this galaxy?

    • Re:Star Question (Score:5, Insightful)

      by helioquake ( 841463 ) * on Wednesday January 11, 2006 @10:38PM (#14451053) Journal
      What's the humidity inside your room? It's not completely dry, right? So, why don't you see a white patchy cloud in your room? Not even in summers?

      Why?

      Well, it has to do with the density. Even if there is a galaxy nearby, if the content of a galaxy is sparcely populated by ordinary stars (and they are, I RTFA), you ain't gonna see them. Just like you don't see "humidity" (water molecules) in your room.
      • What's the humidity inside your room? It's not completely dry, right? So, why don't you see a white patchy cloud in your room?

        Actually this is because humidity as we know it is a measure of water vapour, which is in fact colourless and damn near transparent. Clouds are visible because they're actually condensed droplets of liquid water, and they reflect and scatter light. It's possible to have a relative humidity within a cloud that's actually lower than 100% overall, but you can have the humidity in your r
        • Actually this is because humidity as we know it is a measure of water vapour, which is in fact colourless and damn near transparent.

          You've apparently never been in Memphis in the summer. You can see 90% humidity. Not within the confines of a room, but 100 feet or more away it can become noticable. Half a mile away it's absolutely obvious. I'd call it translucent, not transparent.

    • Imagine it as such.

      You're an observer looking across a field covered in a fog of a certain turbidity. Now, I disperse a spherical cloud of smoke at some distance from you in that field.

      Assuming similar colour and only slightly different turbidity, then you're most helpful factor in noticing the cloud is seeing the edges delineating it. If the cloud covers a very wide field of view, you'll tend to just look through it, unregistered. A combination of low contrast and minimal local variation in structure (

  • Some SDSS info (Score:5, Informative)

    by Michael Woodhams ( 112247 ) on Wednesday January 11, 2006 @10:26PM (#14450996) Journal
    I was a graduate student at the Astrophysical Sciences deptarment at Princeton when they were planning and starting to build the SDSS. A few interesting facts:

    Some very clever optics (designed by James Gunn) went into the telescope. Normal telescopes do not produce the large field of view required. There were existing specialized telescopes which did (Schmidt cameras) but they have the imaging plane in the wrong place.

    The main camera uses 30 2k x 2k CCDs, cooled by liquid nitrogen. At the time (early '90s) these cost on the order of $200k per chip.

    The camera works in "drift scan" mode: the telescope moves such that the images of the stars drift along the columns of detectors in the CCDs. The packets of charge are shifted along the CCDs at the same rate - so instead of producing distinct individual frames, it continuously outputs data along an ever-lengthening strip along the sky. As I recall, the data rate is about 8Mbyte/s.

    The camera spends rather more time on spectroscopy than imaging. (The imaging is primarily about selecting targets for the spectroscopy.) The spectrograph does 640 objects at a time. A computer-drilled plate is (manually) plugged with fibre optic cables in the right positions for that field of sky.

  • like looking at the milky way through 3d glasses (Score:5, Funny)

    by themysteryman73 ( 771100 ) on Wednesday January 11, 2006 @10:27PM (#14451002)
    "It's like looking at the Milky Way with a pair of 3-d glasses," said Princeton University co-author Robert Lupton.

    I wonder where he got 3d glasses that make stuff look 3d in real life? I could use some of them to stop walking into walls so much!

  • Appearance from outside (Score:4, Insightful)

    by CaptainCarrot ( 84625 ) on Wednesday January 11, 2006 @10:35PM (#14451044)
    If you've ever wondered what it was like to live on a planet in one of those exotic galaxy-eating-galaxies that we've seen in various images from Hubble and others --

    Well, now we know. Little did we know that we knew all along.

    • I don't know about you, but I wonder about how it would be to live in a real galaxy-eating-galaxy rather than the very common galaxy-eating-dwarf-galaxy we currently live in. There are some pretty well argued theories out there that suggest the spirals are created by dwarf-galaxy eating, and remain for some time after as the shockwaves travel around.

  • Very cool! (Score:4, Funny)

    by lawpoop ( 604919 ) on Wednesday January 11, 2006 @10:49PM (#14451095) Homepage Journal
    This is like that part in the movie or the comic book, where the guy is tripping out or whatever, and he's staring into the dark void of space, and then slowly he realizes he's staring into a GIANT FUCKING EYE!
  • I'm hard pressed to think of a better oxymoron...

  • Why women are smarter than /.ers (Score:3, Funny)

    by Honkytonkwomen ( 718287 ) on Thursday January 12, 2006 @12:07AM (#14451467)
    They know you're lying when you tell them "You can't see it because it's so big".
  • I for one welcome our not-so-benevolent ascended Ancients.
  • I, for one, welcome our new galactic neighbors!
  • When in an argument, people who vaguely rely on something 'scientific' they once read will persue a cycle of 'I read this scientific thing', 'what do you mean science doesn't know everything', 'are you disputing these great scientists!'. This is a manouvre by dimwits to use someone elses published intellect as ammunition for their own weak arguments.

    Even with supposedly 'intellectual sciency' people like those on slashdot, you only have to subscribe and read my torrid posts with 'darwinists' (read, people w
  • There's a classification of galaxies known as Malin-type, which refers to their being at the extreme end of low density and luminosity. Malin-types can be spiral and a thousand times larger than our own Milky Way (LOL!), yet only have a few million active stars within; little is known about these supergiants, but the fact that they do organize themselves into spiral structures and that most of their mass is spread so thinly that it has not and maybe cannot create pockets of concentration that will achieve

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