The sun, moon, Mercury, Venus and Mars. Owing to their relatively short orbital periods, these planets can be in different signs of the zodiac in the charts of individuals born in the same year or even the same month - for example, the moon changes signs every 2 1/2 days. They contribute a highly individualistic character to each birth chart. They represent the following themes of a personal nature: personal consciousness or sense of identity (sun); emotions (moon), communicative abilities and learning capacity (Mercury); aesthetic sense and relationships (Venus); and assertiveness (Mars). The personal planets are distinguished from the social planets (Jupiter and Saturn) which can spend one to 2.5 years in a sign or house; and spiritual or generational planets (Uranus, Neptune and Pluto.) They spend so long in one sign that they can typify a generation of people.