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What color is the sky?

  1. Oct 14, 2009 #1
    What color is the sky on extra-solar planet?

    Hi I'm writing a story and I need to figure out what color the sky is on a planet orbiting Zeta Tucanae that has close to the same atmosphere as earth.

    just so you know Zeta Tucanae's Spectrum is F9V and Color Index is 0.576

    It would be great if you can tell me how to find the color myself, or direct me to something that will, that way I won't have to bug you guys in the future.

    Thanks alot,
    Last edited: Oct 14, 2009
  2. jcsd
  3. Oct 15, 2009 #2


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    Welcome to PF!

    Hi Dan! Welcome to PF! :smile:

    F9 is only two grades hotter than the Sun (the Sun is G2, and it goes F9, G1, G2, …), so the intrinsic light will be pretty similar.

    But the sky colour really depends on the thickness of the atmosphere, and whatever's suspended in the atmosphere.

    The Sun's light is actually white, but Earth's atmosphere is so thick that diffraction makes the sky blue and direct sunlight yellow.

    (btw, I've never really understood why the Moon doesn't also look yellow, on that basis :confused:)

    On Mars, the sky is red, but that's only because of all the red dust in it. :wink:
  4. Oct 20, 2009 #3


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    From http://en.wikipedia.org/wiki/Rayleigh_scattering#Rayleigh_scattering_from_molecules"
    Last edited by a moderator: Apr 24, 2017
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