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Color of the Clouds.

  1. Jun 27, 2009 #1
    Why is the color of the clouds dark pink in the night as compared to the black sky? Also..why is it white in the morning when the sky is blue..(is it because the cloud molecules scatter red wavelengths along with the blue ones? )
  2. jcsd
  3. Jun 27, 2009 #2


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    I've never seen pink clouds at night, unless you're talking about immediately after the sun sets. In that case, the sun is below your horizon, but the clouds are high enough up that their horizon is farther away. They just reflect what you previously saw as a red sunset.
    Remember that clouds are merely water droplets along with some impurities such as dust and airborne pollutants.
  4. Jun 27, 2009 #3
    Oh no..im not talking about the time when the sun sets.. Actually it's the monsoon season here..and the rain clouds appear pink in color against the black sky late in the night much after the sun has set. so ...i dont really know what must be happening in this case?
  5. Jun 27, 2009 #4


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    If it is long after sunset, the only things that could illuminate the clouds is light from the ground or the moon.
  6. Jun 27, 2009 #5

    Andy Resnick

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    The color of the clouds comes from scattering, and there are many, many relevant scattering processes that can occur depending on the relative positions of the sources (sun, 'light pollution'), the observer (you) and clouds; the composition of the clouds, the polarization dependence, etc. etc.

    Here's a great site to surf around:

  7. Jun 27, 2009 #6
    wow..maybe it is light pollution ! because i live in a metropolis...
  8. Jun 27, 2009 #7


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    I live in Toronto, and the clouds here are yellow/orange at night due to the city lights. But your clouds are pink?
  9. Jun 27, 2009 #8
    I dont know why the colour is pink? Maybe it's because of some other reason.And the colour is a dirty pink.Im from Mumbai...
  10. Jun 27, 2009 #9
    Maybe there's a large red light district hidden in the middle of your city? :biggrin:
  11. Jun 27, 2009 #10


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    If there's a lot of heavy manufacturing around, maybe iron dust is getting into the air?
  12. Jun 28, 2009 #11
    No...that cant be...because i'm staying in a residential area. Ald my house faces the sea. The clouds on top of the sea also are pink in colour! They're slightly dirty pink(pink mixed in murky black?)
  13. Jun 28, 2009 #12
    Speaking of sunset colours, can anyone tell me about the saying, "Red sky at night, shepherd's delight; red sky in the morning, shepherd's warning". I understand it is to do with predicting the weather. I do not know how accurate it is though.
  14. Jun 28, 2009 #13


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    I donlt know about accuracy, but http://en.wikipedia.org/wiki/Weather_lore#Red_sky_at_night" regarding the rationale of the saying:

    "Weather systems typically move from west to east, and red clouds result when the sun shines on their undersides at either sunrise or sunset. At these two times of day, the sun's light is passing at a very low angle through a great thickness of atmosphere, the result of which is the scattering out of most of the shorter wavelengths — the greens, blues, and violets — of the visible spectrum, and so sunlight is heavy at the red end of the spectrum. If the morning skies are red, it is because clear skies to the east permit the sun to light the undersides of moisture-bearing clouds coming in from the west. Conversely, in order to see red clouds in the evening, sunlight must have a clear path from the west in order to illuminate moisture-bearing clouds moving off to the east."

    In a nutshell:
    A red sky at night means the sky is clear to the West, where the sun is setting. That clear weather will be arriving in the morning.
    A red sky in the morning means that clear weather that has passed over is now in the East, and the sun's red rays are now lighting up the incoming, wet clouds.
    Last edited by a moderator: Apr 24, 2017
  15. Jun 29, 2009 #14


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    Maybe it is dust or a sand storm if you are in the middle east.
  16. Jun 29, 2009 #15
    If you're are saying that the clouds appear white during the day and the sky blue and that they clouds appear reddish and so does the sky at sunset then this is what everybody sees. Two words 'Rayleigh Scattering'.

  17. Jun 29, 2009 #16


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    He's not saying that. He addressed this very question in https://www.physicsforums.com/showpost.php?p=2252108&postcount=3":

    Last edited by a moderator: Apr 24, 2017
  18. Jun 29, 2009 #17


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    yash25, Google nocto-luminescent clouds.

    (Or variations such noctoluminescent, noctiluminescent, nocto-luminescent.)
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