Why Do We have Seasons? As the earth spins on its axis, producing night and day, it also moves about the sun in an elliptical (elongated circle) orbit that requires about 365 1/4 days to complete. The ...

Visible light travels in electromagnetic waves, which we see as the colors of the rainbow. Different colors have different wavelengths of light. Violet and blue have the shortest wavelengths, whereas ...

There are very special cases, when the sky is very clear and exceptionally transparent, that a green flash can be glimpsed just as the very topmost part of the sun is rising or setting. When you ...