... Day З In common usage the word "day" unfortunately has two different meanings: (1) the period of time when the Sun is up (what we have been calling "daytime") (2) the period of time between consecutive sunrises (or sunsets), or one daytime + one nighttime. ... The sky turns dramatically dark and bright stars and planets can be seen. ... З The planets move roughly along the same path as the Sun and Moon. ... The Moon took a month to circle the sky, the Sun a year, each planet its own period of time. ...