1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The sky's red color during sunset and sunrise

  1. Dec 14, 2012 #1
    I understand why the sun is red,, due to most of the blue light of shorter wavelength being scattered in other directions because the sunlight has to travel through more atmosphere before it reaches our eyes, but why does the surrounding sky appear red to us?
  2. jcsd
  3. Dec 14, 2012 #2


    User Avatar
    Gold Member

    Got a good answer by Googleing "why are sunsets red"
  4. Dec 15, 2012 #3
    I know why sunsets are red, but I want to know why the sky surrounding the sun is red.
  5. Dec 15, 2012 #4


    User Avatar
    Staff Emeritus
    Science Advisor

    Why is the sky surrounding the Sun red during a sunset? Scattering of light and refraction. Red light is still scattered by the air, and during a sunset the light has to go through so much air that most of the blue light is already absorbed, leaving the longer wavelengths to get through. But even these longer wavelengths are still scattered some, so you see the reds and oranges since they actually make it through the atmosphere to you. Also, look closely as the Sun goes down and you should be able to see a subtle rainbow effect, with the colors changing as you get further away from the horizon due to refraction from the atmosphere.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook