Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Structure of the Milky Way?

Tags:
  1. May 20, 2012 #1
    I and a few friends thought about the oort cloud...
    If it has 2 light years in lenght, thats half way to Alpha Centauri...
    What would stop our near neighbor Alpha Centauri to have its own oort cloud...
    And if this is wright couldn't the galaxy be filled with dwarf planets, asteroids and comets rather than empty space between the stars as usual sci-fi movies like to show?
     
  2. jcsd
  3. May 20, 2012 #2
    Yes the galaxy is filled with asteroids, comets and dwarf planets, but that doesn't mean that you would bump into one celestial body after another when passing through it. The distances between these objects are so enormous that you would have to carefully aim in order to hit something. The sci-fi movies actually got it right. The space is mostly empty.
     
  4. May 20, 2012 #3
    Could we actually Colonize some of those wild planets... if they are big enaugh?
    i mean i think they can get to the size of earth or biogger, no?
     
  5. May 20, 2012 #4
    ^ Spell check.

    It's not very easy to answer speculative questions. The Kepler satellite is searching for Earth-sized planets, so if we were to ever colonize a planet, it would more than likely be a planet similarly sized to earth (obviously).
     
  6. May 21, 2012 #5

    Chalnoth

    User Avatar
    Science Advisor

    Do you mean a rogue planet? As in a planet-sized object not anywhere near a star? They'd be far, far too cold to colonize.
     
  7. May 21, 2012 #6
    Oke...
    Cold let it be, we could have hitting systems inside huge metropolises covered by some kind a dome but not made of glass as it is too fragile...
    or we could make a strong enaugh glass so we could also se the galaxy trough it...
    eeeeeh... this kind a colonization is more for fun... imagine this small scene: in the darkness of space in a huge cluster of planets, Dwarf and partially borken planets, dwarf planets, comets and asteroids surrounded by a shinning blue nebula but thin enaugh to se the galaxy trough the glass domes of our colonies... wouldn't that be nice:approve: even spectacular if i say so...:tongue:
    man this chat is more because i'm REAAAAAAALLY bored
     
    Last edited: May 21, 2012
  8. May 21, 2012 #7

    Drakkith

    User Avatar

    Staff: Mentor

    Did you have a specific question?
     
  9. May 21, 2012 #8

    Chalnoth

    User Avatar
    Science Advisor

    It's more a problem of having the energy to actually do anything.

    Maybe if we solve the problem of getting nuclear fusion reactors off the ground, maybe it will be possible. But why bother with that when there are likely to be billions of candidate planets in our galaxy within the habitable zones of stars?
     
  10. May 21, 2012 #9
    True, but the majority of those candidates are planets found in the solar system of a red dwarf, which means that the habitable zone of these planets is required to be a lot closer than the earth is to our sun, which opens up complications like harmful radiation.

    Then again, once we get to the point where we can colonize other planets, I doubt we would want to be too picky :)
     
  11. May 21, 2012 #10

    Chalnoth

    User Avatar
    Science Advisor

    Well, that's more a feature of the fact that it is technically more difficult to detect planets which have orbits closer to one year here on Earth than it is to detect these closer-in planets. I doubt that there is any real bias towards red dwarfs where habitable-zone planets are concerned.

    Of course, most stars out there are red dwarfs, but there are one heck of a lot of yellow dwarfs around as well.
     
  12. May 24, 2012 #11
    For posterity man!:biggrin:
    To show the galaxy how kool can we get:approve:

    I agree with you, Chalnoth,
    But couldn't we colonize a few planets that orbit around Blue giant stars???
    If there are any solid ones... or...:confused:
     
  13. May 24, 2012 #12

    Chalnoth

    User Avatar
    Science Advisor

    Well, blue giants tend to have rather short lifetimes, and when they die they explode in massive supernovas. So they would be rather hazardous places to live.

    Yellow dwarfs, like our own sun, are pretty much ideal. Much smaller, and they are quite volatile when young and the habitable zone is in very close to the star, making it unlikely that they have genuinely habitable planets. Much larger, and the lifetime of the star shortens significantly, often with many rather violent episodes before the final supernova. Yellow dwarf stars, though, last quite a long time (billions of years) and are relatively quiescent.
     
  14. May 25, 2012 #13
    Posterity, remember let's harvest some adrenaline...:biggrin:
    Till the time comes when we could even control a supernova or just live trough the exploding giant we are most surely going to search for planets orbiting yellow dwarf and red dwarf stars...

    But hey... a small imaginary jump in the future jus may feed our will to explore space and get us a bit a fun!:approve:

    (In the future we would have colonized planets that have close orbits to black holes...:tongue:)
     
  15. May 25, 2012 #14
    one thing that i don't understand... Why are there more red dwarfs than any other type of stars?
     
  16. May 25, 2012 #15
    because they spend a very long time as red dwarfs, whereas giant stars don't last very long
     
  17. May 25, 2012 #16

    Drakkith

    User Avatar

    Staff: Mentor

    That plus red dwarfs are very easily made as they require much less material than larger more massive stars. When stars form from a collapsing gas cloud you typically have many more small stars created than larger stars.
     
  18. May 25, 2012 #17
    I don't understand your reasoning at all. Isn't the idea of colonizing other planets far-fetched enough for now? Let alone colonizing unfavorable and unforgiving planets near black holes?

    It's good to be excited about these things, but you need to stay slightly realistic. If the only reason to inhabit certain areas of the universe is just for the hell of it, or just to show that we can, then I think we would need to question the intelligence of the people authorizing those missions.
     
  19. May 25, 2012 #18

    Chalnoth

    User Avatar
    Science Advisor

    Smaller objects tend to be far, far more numerous than larger ones.
     
  20. May 25, 2012 #19
    We should never colonize planets outside our own solar system. Expansionism unavoidably leads to war. And war with a high technology level likely leads to extinction for all sides involved.
    I know that doesn't sound good for SF movies and for people's imagination, but it's closer to reality.

    On the other hand, small outposts can be built anywhere. But why on a rogue planet in the middle of nowhere ?
     
  21. May 25, 2012 #20

    Chalnoth

    User Avatar
    Science Advisor

    I don't quite see why. It's highly unlikely that we'd ever run into another space-faring civilization, if it is even technically possible to expand beyond our own solar system. Because if such civilizations were that common, they'd probably already be here.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Structure of the Milky Way?
  1. Speed of the milky way (Replies: 3)

  2. Viewing the Milky Way (Replies: 7)

  3. Viewing milky way (Replies: 3)

Loading...