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New Galactic Neighbor

Posted by samzenpus on 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."

9 of 200 comments (clear)

  1. Re:How do they define a galaxy? by Yahweh+Doesn't+Exist · · Score: 2, Insightful

    >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.

  2. Re:How do they define a galaxy? by FalconZero · · Score: 5, Insightful
    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 (pretty pictures included).
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    Windows in 6 Bytes (IA-32) : 90 90 90 90 CD 19
  3. Dwarf galaxy by Chess_the_cat · · Score: 2, Insightful
    "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?

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    Support the First Amendment. Read at -1
  4. Appearance from outside by CaptainCarrot · · Score: 3, Insightful
    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.

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    And the brethren went away edified.
  5. Re:Star Question by helioquake · · Score: 4, Insightful

    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.

  6. Re:I swore I'd post one of these.... by x86eon · · Score: 1, Insightful
    I hate myself already
    No wonder! Your comment will probably be modded redundant! :P
  7. Re:How big is a full moon? by Anonymous Coward · · Score: 1, Insightful

    Average sized orange? What time of year? Are we talking California Navel Oranges, or Clementines?

    A Summer-Ripe Clementine about 2.5" in diameter at 1 meter is about the same size of a Quarter(USD) at a few inches. [Actal Experiment by me]

    (Sorry, I just had to use that against you...)
    ;
    ;
    ;
    ; ;-) FIRST POST! YAY!

  8. Re:How do they define a galaxy? by FalconZero · · Score: 2, Insightful

    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 interaction with other entities (IE Indirect detection).

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    Windows in 6 Bytes (IA-32) : 90 90 90 90 CD 19
  9. Re:Wrong priorities... by hywel_ap_ieuan · · Score: 2, Insightful
    if you consider that we are the aliens, and our species has simply invaded and conquered this planet an aen ago. We adapted, survived, and destroyed our own history.
    It's a fun idea, and as others pointed out, Larry Niven did some interesting work with it. But it doesn't hold up in light of the facts of biology and paleontology. Our physical features and our genes both say we're closely related to the other great apes, which are related to the other primates, which are related to other mammals, and so forth. The fossil record, fragmented as it is, shows that our predecessors were increasingly 'ape-like' as you go back in time. If we were aliens, we'd expect the evidence to be very, very different. Our genetic code - the translation mechanism, not just the genes - would probably be different. We might share some gross features with some native species, but the deeper into the details you get, the less likely it is that we'd be the same.

    And as for destroying our own history - there are far more traces of civilization than written materials. Technology leaves evidence. We have found tools and weapons and such from hundreds of thousands of years ago. Anything more complex would not only survive in and of itself, but the infrastructure to create it would leave parts laying around. Don't bother talking about wars and catastrophes. Besides the fact that they don't erase everything, they leave their own evidence behind.

    Sorry for the fun story, but we're natives. Our ancestors have been here on earth for over three billion years.