As we see every day in the morning the sun shows a red-orange colour but at midday has a blue-white like colour why?

Is it concerned with the distance from the earth or about intensity? How do you see it?

  • $\begingroup$ See physics.stackexchange.com/questions/17/… $\endgroup$
    – PM 2Ring
    Apr 2, 2019 at 5:55
  • 1
    $\begingroup$ Related: extinction, air mass. I think this is on topic. $\endgroup$
    – Mike G
    Apr 2, 2019 at 18:05
  • $\begingroup$ Add to that that the air scatters out more of the blue light (which is why the sky is blue), leaving the reddish light. $\endgroup$
    – Ken G
    Apr 2, 2019 at 23:28
  • $\begingroup$ I'll explain very easy: It's just a matter of light and air. Light travels more in the morning through the atmosphere so it lose more energy (becomes red), while it travels less at midday through it so it don't lose so energy (becomes blue). Quite simple. Right? $\endgroup$
    – User123
    Apr 4, 2019 at 12:25
  • $\begingroup$ This is a question for Earth Science and it is already answered there. $\endgroup$
    – user1569
    Apr 19, 2019 at 6:18

2 Answers 2


Sunsets are red because the sky is blue.

Air, while it appears colorless actually scatters light just a bit. This is not the same as absorbing the light, but more like how light is scattered by fog. If you are driving through fog with your headlights on, part of the light from their beams bounces off the fog particles and lights up the fog well outside the beam and some of it even bounces multiple times coming back to your eyes.

Air is much clearer than fog, but it does scatter light just a bit. What's more, it scatters blue light more than green, and green more than yellow, and yellow more than red. So while the Sun's light in space is quite white, as it passes through the atmosphere on a sunny noonday a lot of the blue light gets scattered, while very little of the red does. That blue light bounces many times and is the source of the blue sky light. The loss of that blue light makes the sun appear redder.

At noon, the light comes down from high overhead and passes through a minimal amount of atmosphere and only some of the blue light is scattered. At sunset (and sunrise) the light comes in at a long, low slant and passes through much more of the atmosphere, and nearly all of the blue and even most of the green is scattered (and much light is absorbed, too), leaving mostly red and orange light left.

Hence the reddened sun.

See Why Is the Sky Blue? and Why Is the Sunset Red? for a bit more including some diagrams.


Neither. As @User123 commented, it depends on the angle between where you are and the Sun. If the Sun is low in the sky, sunlight has to travel through much more of the atmosphere than at midday when the Sun is higher in the sky. The intensity of the Sun is basically constant, and the distance from the Sun does not vary between morning and midday.


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