Phases of the Moon. The moon cycles 13 times a year through phases, each of which influence us just like the pull of the tides. It starts with the New Moon, which carries the energy of new beginnings, this is a great time to focus on stepping into something new. Then the Full Moon, Signifies the time of the completion of a project, and finally returns to the New Moon again. This entire cycle occurs over a period of 28 days, and yes, there is no mistaking it, this is the same as women's menstrual cycles, women tend to be much more connected to the moon than men.
People with 'Airy' Moon, (Gemini, Libra or Aquarius) will need to communicate to others their ideas, opinions, ideals, knowledge or beliefs to others in order to feel right about themselves. Finding out, learning and passing on information on will be nourishment for them, as well as a good conversation with like-minded or intellectual people. Curiosity and the need to know could be the thing that forces them out their comfort zone. Negatively they could be too influenced by others options, be indecisive or simply a 'gossip'.
Envision that astrology is made up of the study of all of the planets and the sun. The astrological birth chart and the study of how planetary alignments affect sun signs are based on these aspects of astrology. The moon actually influences this overall picture, and can cause certain aspects of astrological phenomena to influence our lives differently than was otherwise predicted.