The true light that leaves the sun is white. That is, it contains ALL colors of light.
Whenever you see the sun ... OR see anything that's lit up by the sun ... the light you see has passed through the atmosphere. The light passes through the LEAST amount of atmosphere at Noon, and the MOST of it at sunrise and sunset.
The amount of atmosphere the light must pass through determines which wavelengths are absorbed (soaked up, subtracted), and how much. When the light finally reaches where we are, we see what's left of it.
