Best Video/Why is it dark at night? (Why is it Dark at Night?)

{{Application:Wikilook Blog/Article
 * blog=Best Video
 * module=Article
 * author=Gaijin
 * publishingtimestamp=2012/10/16 21:00
 * title=Why is it dark at night? (Why is it Dark at Night?)
 * categories=Science
 * leading=Why is it dark at night?
 * text={{ Widget YouTube Advanced | id = gxJ4M7tyLRE | width = 560 | height = 315 | language = en_US }}