What causes different colors to appear in the sky?

If you are talking about a rainbow it is refraction happening from light passing through precipitation. If you a talking about for example a sunset, it is the sun's light being displaced as the Earth orbits it. The normal color that should show after the sun's light passes through the atmosphere is blue.

answer by yourhope:

how do models compare to real-world objects?

d. most models represent a real-world object in a simpler way.

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