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What I see in sky - Milky Way, other stars

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  1. Jan 27, 2009 #1
    I've wondered about this for a while:

    -the Milky Way which we are part of appears to be a white cloudish streak in the sky. I guess this is because the stars are so far away that it appears as a cloud of light?

    -But I would assume that all the stars in the Milky Way, our own galazy, must be closer to us than stars in other galaxies?

    So,

    1- why is it that I can see individual stars in the sky, but not individual stars in the milky way?

    2- And conversely, Why can I see individual stars (that must be part of other galaxies?), without the same 'cloud' effect from thier home galaxy? I mean, these stars must be so much further away, so why would they appear alone and clear, when the stars in our own galaxy appear so muddled?

    Thanks,
     
  2. jcsd
  3. Jan 27, 2009 #2

    turbo

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    The stars that you can see as individuals are all part of our own galaxy and many of them are relatively nearby. The Milky Way that you see as a "streak" is actually the galactic plane of our spiral galaxy (the densest concentration of stars) and many of the stars on our line-of sight are not distinguishable as individuals.
     
  4. Jan 27, 2009 #3
    Well that clears a lot up then... about 29 years of the wrong mental model on this one. I didn't realize that. Thanks.



    Seems pretty boring now though... just kidding... kind of. I'm going to have to go buy one of those hubble dillies to check out all those galaxies now.
     
  5. Jan 27, 2009 #4

    Nabeshin

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    If you have moderately dark skies, you should be able to see M31 with the unaided eye :)
     
  6. Jan 27, 2009 #5

    berkeman

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  7. Jan 27, 2009 #6

    turbo

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    Very true. In the southern hemisphere, you can see the Magellanic clouds which are companions of our own galaxy. The nearest galaxy of comparable mass to the Milky Way is M31 (seen through the constellation Andromeda) and it is visible to the naked eye in reasonably dark skies in the northern hemisphere.
     
  8. Jan 27, 2009 #7

    turbo

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    Thanks for linking that, berkeman! I am a member of the Our Dark Skies forum, and other long-time members routinely get APOD nods. In particular Diets, a surgeon, does fantastic work, and Greg and Noel (a Brit imager and a Floridian image processor) have a fantastic picture-book in the works. I know, because ODS members routinely get to see their images as works-in-progress. If anyone here is interested in astrophotography, I highly recommend that they join ODS. Noel Carboni has developed a powerful suite of actions for Adobe Photoshop and CS packages to greatly streamline image processing, and he will give a free set of these actions to any ODS member.

    http://forum.ourdarkskies.com/
     
  9. Jan 27, 2009 #8

    DaveC426913

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    ...and with reasonably young eyes.


    A qualifier you don't know is applicable until it's too late...
     
  10. Jan 27, 2009 #9
    Wow, yes that is quite the APOD photo... beautiful. While googling the milky way before posting I ran across the photo below, which is pretty striking as well.




    http://en.wikipedia.org/wiki/File:Deathvalleysky_nps_big.jpg


    I'll keep an eye out for this M31... pretty clever name, its gotta be good.
     
  11. Jan 27, 2009 #10

    turbo

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    It is called M31 because it was the 31st object cataloged by Messier. Messier was a French astronomer who wanted to compile a list of objects that might be confused with comets. Comet-hunting was all the rage then, and his catalog was intended to reduce the number of false-sightings.

    BTW, when you see images in which the galactic plane of our MW is curved, it is an artifact of wide-angle photography. The MW's galactic plane is quite flat, with a bulge in the direction of the constellation Saggitarius.
     
    Last edited: Jan 27, 2009
  12. Jan 27, 2009 #11

    Hey get out of my head!! You're reading my mind now :smile:

    I was just wondering that very thing while looking at the two pictures... I was picturing looking out from one of the MW spiral arms towards the center, and it wasn't adding up that it would be seen as curved. Thanks again!
     
  13. Jan 27, 2009 #12

    turbo

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    Mmmmmm! Donuts!
     
  14. Jan 27, 2009 #13

    berkeman

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    No, no, no. Mmmmmmm Beeer!
     
  15. Jan 27, 2009 #14

    turbo

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    Not at work, berkeman! When you're an operator in a nuclear power plant, you can only have beer before and after work and maybe on breaks. Donuts at work-stations???? Perfectly acceptable.
     
  16. Jan 27, 2009 #15
    Well thats right for sure, if I got drunk at the panel then how would I drive home?
     
  17. Jan 27, 2009 #16

    turbo

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    More to the point, how you find your way to Moe's so you could have "just one more"?
     
  18. Feb 3, 2009 #17
    This is a somewhat related question, so I figured I'd add it here instead of just starting a new thread.

    I'm 26 years old, and I've never seen the Milky Way (meaning the galactic plane) before. I live on the outskirts of Baltimore, so it's just too bright around here. If I drive about 20 miles from the city lights, I can see maybe a few dozen stars out. At my house (2 miles from the city line,) I struggle to see 20-30. From my house, the Pleiades, for example, looks like a fuzzy patch of very pale light that looks like it may not be real at first.

    How far away from the city lights do I need to travel to see the Milky Way? Think there would be anywhere within an hour of Baltimore, MD where I could actually see the galactic plane?
     
  19. Feb 3, 2009 #18

    DaveC426913

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    This might have more to do with your night vision. I live in the burbs of Toronto, a city of 4 million people, and my 44 year old eyes can see hundreds or even thousands of stars if I go to a dark park.

    Also, if the Plaeides are a fuzzy patch, that would definitely point to a vision thing. If it's dark enough to see it at all, you should be able to be able to make out at least 5 distinct stars visible in the shape of a "tiny dipper".
     
  20. Feb 3, 2009 #19

    mgb_phys

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    It is stunning from a dark site, especially in the southern hemisphere.
    The first time I saw the milky way from our observatory in Chile I thought it was a cloud.
    You can't see it on Hawaii, the low oxygen at altitude wrecks your night vision.
     
  21. Feb 3, 2009 #20

    DaveC426913

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    I did not know this.

    Waitaminnit; I still don't. Hawaii is at sea level. I presume you mean from the observatory...
     
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