Astronomy Question of the Week: Why is it dark at night?

Because the Sun does not shine at night, of course! Or, more precisely, because sunlight does not reach the side of the Earth that is facing away from the Sun.
This answer is not sufficient for astronomers. Just like being in a large forest, where in every direction and in our entire field of vision [...]

Full story at http://spacefellowship.com/2009/12/21/astronomy-question-of-the-week-why-is-it-dark-at-night/