The word "equinox" translates from Latin as "equal night," although because the sun is not a point, the length of day and night are not exactly equal. They are both, however, almost exactly 12 hours.

Thursday, March 20, the date of the spring equinox, marks the first day of spring in the United States. The spring equinox lands at 5:01 a.m., the precise moment the sun's rays shine directly on ...