Follow Slashdot blog updates by subscribing to our blog RSS feed

 


Forgot your password?
Close
typodupeerror
×
Space Science

Mysterious MilkyWay Warp Finally Explained? 215

Posted by ScuttleMonkey from the like-a-hot-chocolate-bar dept.
* * Beatles-Beatles writes to tell us Space.com is reporting that scientists think that a collision between mysterious 'dark matter' and two of the Milky Way's nearby neighbors may be causing our galaxy to warp 'like a vinyl record left out in the hot Sun.' From the article: 'The warp is most clearly visible in a thin disk of hydrogen gas that extends across the entire 200,000-light-year diameter of the Milky Way. Viewed sideways, one half of the hydrogen disk appears to stick up above our galaxy's plane of stars and gas, while the other half dips below the plane for a bit and then rises upward again farther away from the galaxy's center.'"
This discussion has been archived. No new comments can be posted.

Mysterious MilkyWay Warp Finally Explained? More

Mysterious MilkyWay Warp Finally Explained?

Comments Filter:

  • related article (Score:4, Interesting)

    by User 956 ( 568564 ) on Monday January 09, 2006 @11:37PM (#14433330) Homepage
    There was a related article in November-- with evidence pointing towards a massive black hole at the center of the LMC. [physlink.com] (The Milky Way's closest neighbor)

  • hmm (Score:5, Funny)

    by Anonymous Coward on Monday January 09, 2006 @11:38PM (#14433333)
    Perhaps this is because the two-thirds of the people on Earth are fat [newyorker.com]. This could result in the part of the galaxy that Earth is located in to be weighed down which is warping the entire Milky Way.

    'McDonalds: Changing the world -- literally'

  • missing info (Score:2, Insightful)

    by amazon10x ( 737466 )
    The article fails to say (or perhaps I missed it?) how severe the warp is nor how fast the warping is happening currently. Furthermore, it doesn't say when this warping was first recorded.

    • Re:missing info (Score:3, Informative)

      by maggard ( 5579 )
      Ignoring the dubious submitter of the story...

      The Milky Way is b-i-g. The warping is not happening on a scale we'd see in our lifetimes. Indeed it likely started when the Earth was still a rock with scum problem. It'll continue long past the date the Earth is a rock with a dust problem.

      Don't panic.

      While dark matter (& energy), galactic distortions, and giant black holes are interesting cosmologically (and further our understanding of the universe) there's no need to start digging a hole in the bac

  • How do we know our own shape? (Score:5, Interesting)

    by bronney ( 638318 ) on Monday January 09, 2006 @11:51PM (#14433376) Homepage
    I've always wondered, how do we know our own galaxy's shape? From our point of view. do we just look 360, more stars there, less stars here, therefore we're on the rim side of the galaxy?
    • I've always wondered, how do we know our own galaxy's shape? From our point of view. do we just look 360, more stars there, less stars here, therefore we're on the rim side of the galaxy?

      In clearer areas, like high elevation or low humidity, and away from light pollution, you can practically see it with the naked eye.

      But beyond that I'm sure they've whipped together a few models with super computers to demonstrate it.

      Besides, our galaxy isn't warped, it's Bent!

    • Stellar parallax [wikipedia.org]. Picture Homer Simpson watching a donut slowly rotating in front of his mouth.

    • Re: (Score:2, Funny)

      by account_deleted ( 4530225 )
      Comment removed based on user account deletion
    • Pretty much.. all you're missing is distance calculations.

      The Milky Way actually looks like a blurry band across the sky. The stars are too dense to make out with the naked eye, so we just see a bright "stripe." It's clearly visible anywhere near the equator or farther south, depending on the time of the year. I happen to live on an island 13 degrees north of the equator, and the view on a cloudless night is truely jaw dropping. Alternatively, you can also go to a local planetarium. If you live near Wa
      • The plane of the Milky Way and the Celestial Equator do not coincide, so the Milky Way appears to the north and to the south of the Celestial Equator. Thus the Milky Way is visible from the North Pole on a clear night. Perhaps you're confusing it with the Magellanic Clouds.

    • Re:How do we know our own shape? (Score:4, Informative)

      by Anonymous Coward on Tuesday January 10, 2006 @12:47AM (#14433610)
      the galaxy's general "flat" shape is visible from the milky way being a thin line in the sky. finding out our location in the milky way is a more interesting proposition. due to the obscuring clouds of interstellar matter, we do not see the milky way being brighter on one side or the other, so it appears to be equally bright on both sides. the first indication of us being located toward the rim was the fact that the globular clusters that we observe are mostly on one side of us. when we discovered methods for measuring distances (based on the relationship between the length of a period of a type of star called the "cepheid variable" and its brightness) [first established by astronomer Leavitt], we could measure their distance from us and create a three dimensional map of the globular clusters' location in the sky. using this method, it was determined that the globular clusters are distributed with spherical symmetry about a point in the plane of the milky way (a point which was, as it happens, quite far from our own solar system). by observing that globular clusters are symmetrically distributed around the centers of other spiral galaxies (most notably the andromeda galaxy), we make the inference that our globular clusters' distribution is also centered on the center of our galaxy - and thus we determine our position relative to the center of the milky way.

      well, at least that's how it went down at the beginning of the 20th century. a decade or two later when radio telescopy was developed, we were able to observe these things in a more direct fashion. but it is interesting to follow the historical development of our own location in the galaxy. :)
    • From our point of view. do we just look 360, more stars there, less stars here, therefore we're on the rim side of the galaxy?

      If it was up to visible light only, you'd be right; in fact, I believe it was William Herschel, co-discoverer of Uranus, who first attempted in the late 1700's to make a diagram of the galaxy, based exclusively on visible-light observing. As it turned out, the Milky Way seemed to have a "powder puff" shape and the sun was near the center!

      However, for the better part of the last cen

  • Article summary in Limerick form (Score:5, Funny)

    by melvin xavier ( 942849 ) on Tuesday January 10, 2006 @12:11AM (#14433454)
    There might a crash in the stars
    Whose damage leaves oddly-shaped scars
    Astronomists patter,
    "It might be dark matter
    That's making the warp so bizarre!"

  • Why the world is so screwed up (Score:3, Funny)

    by raider_red ( 156642 ) on Tuesday January 10, 2006 @12:21AM (#14433490) Journal
    I guess we should have known. The whole friggin' galaxy is warped.

  • Vinyl tracks (Score:3, Funny)

    by suso ( 153703 ) * on Tuesday January 10, 2006 @12:23AM (#14433503) Journal
    causing our galaxy to warp 'like a vinyl record left out in the hot Sun.'

    Now that's what I call an extended LP.
  • then it's time to give Facilities a call. It's too hot in the Data Center!

  • Blitz abstract (Score:3, Informative)

    by mattr ( 78516 ) <`moc.ydobelet' `ta' `rttam'> on Tuesday January 10, 2006 @01:40AM (#14433739) Homepage Journal
    Here's the abstract for the presentation by Leo Blitz on the warp. Anyone who was at the AAS, knows someone who does or understands dark matter professionally, how about telling us if this tablecloth fluttering mentioned by Blitz in TFA might be useful as a test of dark matter? Abstract follows.

    AAS 207th Meeting, 8-12 January 2006
    Session 40 Galactic Structure with WIMPS, STARS and Gas
    Oral, Monday, 10:00-11:30am, January 9, 2006, Salon 1

    [40.05] The Shape of the HI Warp in the Outer Milky Way Disk
    E.S. Levine, L. Blitz, C. Heiles (UC Berkeley), M. Weinberg (University of Massachusetts, Amherst)

    Although the warping of the disk of the Milky Way has been known since 1957, our work represents the first time the Milky Way warp has been quantitatively described and we find it to be both elegant and surprising. We examine the outer Galactic HI disk for deviations from the b=0 plane by constructing maps of disk surface density, mean height, and thickness. We find that the Galactic warp is well described by a vertical offset plus two Fourier modes of frequency 1 and 2, all of which grow with Galactocentric radius. The global warp demonstrates approximately an order of magnitude more power in each mode with azimuthal wavenumber m=0,1, and 2 than in any higher frequency mode; thus three and only three modes are necessary to describe the large-scale behavior of the warp. The power in the m=0 and m=2 modes grows starting from around 15 kpc; the m=1 mode is the most powerful everywhere in the outer disk. We outline six observational conclusions regarding the warp that any potential theoretical mechanism must satisfy. We will also show a movie that demonstrates the evolution of the three modes with time.

    ESL and LB are supported by NSF grant AST 02-28963. CH is supported by NSF grant AST 04-06987.

  • Really an explanation? (Score:4, Interesting)

    by Jugalator ( 259273 ) on Tuesday January 10, 2006 @01:42AM (#14433750) Journal
    I guess one *could* call it "explained", although involving this "mysterious dark matter" is much like explaning how the Sun can shine as "we now know the Sun get fueled by some mysterious nuclear process".

    This explanation only highlights our problems with dark matter even more, and things get especially funny if it's later discovered if it didn't exist. Then watch a number of theories fall apart during a night.

    • Re:Really an explanation? (Score:4, Interesting)

      by Markus Registrada ( 642224 ) on Tuesday January 10, 2006 @03:57AM (#14434144)
      And, of course, there's no such thing as "hydrogen gas" in the interstellar medium. Essentially all of it is ionized to some degree, and ionizations of one per 10,000 neutral atoms causes it to behave with dynamics fundamentally differently from neutral gas.

      As a result, all this material (which collectively outmasses the stars sprinkled here and about) responds to other familiar but enormously stronger forces in addition to gravitation. Therefore, any model relying solely on gravitation will depend on such fantastical constructs as "dark matter" to match observations.

      We see similar effects reported as apparent anomalies in galactic rotation, based on measurements of motion of interstellar "gas". To expect the motion of stars in a galaxy to match the motion of the plasma between them is to assume that no electromagnetic forces are in play. This is a popular assumption among astrophysicists, who as a rule never studied any real plasma dynamics in school (although they may have studied MHD, which doesn't apply), but the evidence suggests otherwise.

  • It won't matter much longer (Score:3, Interesting)

    by core plexus ( 599119 ) on Tuesday January 10, 2006 @02:23AM (#14433864) Homepage
    This related story about a massive cluster of Red Supergiants [suvalleynews.com] will make this, and all other space stories, moot.

    Also, global warming will be a thing of small concern.

  • I mean, I understand it's to make observations fit the theory, but what theory, exactly?

    Why can't there just be no dark matter at all?

    To be honest, the whole idea of it and how it just "has" to be there to make observations fit the theory just reminds me of how convinced scientists were of the existence of aether before the Michelson-Morly experiment in the late 19th century.

    • Basically, we look at a galaxy and see how fast parts of it are spinning. From there, we can calculate the acceleration due to gravity on different parts of (a=v^2/r) and set this equal to the gravitational acceleration (a=GM/r^2) to find the total mass inside of whichever part we are looking at (mass outside has no net gravitational effect).

      Once we have gravitationall calculated the mass distribution, we can look at normal images of the galaxy, note that we can only see 5% of that amount of mass, and d

  • Further Research Shows (Score:4, Funny)

    by Timberwolf0122 ( 872207 ) on Tuesday January 10, 2006 @03:38AM (#14434087) Journal
    The additional mass and friction with dark matter is not only causing the milkway to warp like a record in the sun but also results in the milkyway playing at 45 speed unlike other LP class galaxies that naturaly travel at 78.
  • Bah, humbug! That is what happens when the Intelligent Designer doesn't tension the wheel spokes properly...
  • So...a mysterious warp that we can't explain may be explained by something ELSE we can't explain!? Guess the only thing constant is change. Hey, today it's a tree tomorrow it's a dog!
  • Did anyone get the license plate of that galaxy that hit us?

    Where is the insurance company when you need them?

    They killed Kenny, the bastards!
  • Sounds like the name of a new candy bar.
  • * * Beatles-Beatles writes to tell us Space.com is reporting that scientists think that a collision between mysterious 'dark matter' and two of the Milky Way's nearby neighbors may be causing our galaxy to warp 'like a vinyl record left out in the hot Sun.'

    Oh, let me guess... That wouldn't happen to be a Beatles record, now would it?

Slashdot Top Deals

Children begin by loving their parents. After a time they judge them. Rarely, if ever, do they forgive them. - Oscar Wilde

Close