Why does the sky turn different colors during sunrise and sunset?

Question

If it didn’t change the colors, noone would take pictures of them.

In: Physics

Answer 1

Start by drawing two circles around the same center, one slightly larger than the other. The inner circle represents the Earth’s surface, and the larger circle represents the size of the atmosphere.

Then, draw a sun ray coming in from straight above a point. That represents the sun at mid day. Now, draw a sun ray coming to that point from the horizon (i.e., straight across instead of straight up). That is the sun at sunrise/sunset.

Notice how much more atmosphere the suns rays have to traverse during sunrise/sunset compared to midday. That extra distance through the atmosphere results in more sunlight being scattered (on average) in the red wavelengths at sunrise/sunset compared to more blue wavelengths at midday.