The following table shows the zodiac names in Latin, with their English translation and the individuals ' names. It also shows the element and quality associated with each sign. The starting and ending dates of the sun sign are approximate, as they may differ from one year to another (by a day or so), due to the fact that the earth 's orbit around the sun is not synchronous with earth 's rotation (one year does not comprehend a whole number of days). The exact date and time of sign entrance / exit (which is corresponded to the 12 "mid-climates '' within Chinese lunisolar calendar) must be obtained with appropriate software or with the help of an ephemeris.
the movement of earth around the sun is called answers.com
orbit