See Satellite for a discussion of moons in astronomy.
The moon is the earth's only natural satellite. It has an equatorial diameter of 3 476 km and its average distance from the earth is 384 400 km. Only one (and the same) side of the moon is visible from earth.
The moon requires 27 days, 7 hours and 43 minutes for one orbital period, which is the time it takes to pass through the same point on the hourly circle of a fixed star (a sidereal month). This is a shorter period than the one between two identical phases of the moon - for example from new Moon to new moon - which is 29 days, 12 hours and 44 minutes (a synodic month). The moon's average diurnal movement is 13 degrees and 10 minutes.
Viewed from the earth and measured in degrees and minutes of arc, the moon has an average diameter of 31 minutes - because the moon's distance from the earth varies slightly this figure can be somewhat larger or smaller. This is also the same size as the sun which has (again as viewed from the earth) a diameter of 32 minutes of arc. The sun and moon appear to be the same size in the view from earth, something that astrology considers to be highly significant. Knowing that the sun and the moon have a diameter of around half a degree can be useful when trying to judge distances when making astrological observations.
The moon is never retrograde.
The four main lunar phases are: new moon (a sun-moon-conjunction), waxing moon (around the first quarter or separating square), full moon (a sun-moon-opposition) and the waning moon (the last quarter or applying square). (For a more complete discussion of moon phases in astrology, see Lunation Cycle. See Lunar Eclipse for a discussion of lunar eclipses.)
The Moon is related to the goddess and feminine principle in most cultures, although it is masculine in a few, such as in the pre-Christian Norse pantheon and in ancient Egypt, where Thoth was a moon god before the Hellenists assimilated him to Mercury. The diversity of moon goddesses in cultures conquered by the Greeks and Romans is attested to by the large number of moon deities in their mythology.
The oldest Greek goddess is Selene (Semele), whose two daughters were fathered by Zeus. Selene was eventually joined, if not entirely supplanted by Artemis (Latin Diana, Luna), Apollo's twin sister. Artemis was the virgin goddess of hunting and animals. She roamed the forests accompanied by her younger female companions. Any men who showed her disrespect were severely punished and often killed. Artemis nevertheless was one of the patrons of motherhood and childbirth, which probably relates to the analogy of the waxing and full moon resembling pregnancy.
The Greeks also assigned different goddesses to the different lunar phases. As the independent virgin hunter, Artemis usually symbolised the waxing Moon. The matronly, fertile aspect of the full Moon is symbolised by Hera (Latin Juno), wife of Zeus and protector of home and family.
Hekate (Hecate) was goddess of the waning moon and the crone phase in a woman's life. She is an example of a once powerful and revered goddess who was "deposed" by later more male-oriented beliefs. Hekate's prototype, the Egyptian goddess Hekit, presided over childbirth, notably the birth of the infant sun-god each morning. While earlier myths describe Hekate as a supremely powerful and helpful nature goddess, she later became a byword for an evil, fearsome witch.
The Moon is the ruler of the sign of Cancer and exalted in Taurus; it is in detriment in Capricorn and in fall in Scorpio.
The moon rules the stomach and the female breast as symbol for femininity and inborn capability to nourish, together with the womb as an organ of procreation. The moon traditionally rules several bodily fluids, such as lymphatic liquids, breast milk, seminal fluid and the mucous membrane. The Moon is also linked to the the capacity of the nervous system to unconsciously control basic physical processes.
The moon traditionally rules phenomena that modern astrologers give to Neptune, such as the sea and alcohol. It is a primary indicator of one's mother, home, emotional needs, and feelings. It is also associated with mature women, vs. Venus as a symbol of young women.
In astrological interpretation the moon, together with the sun and the ascendant, is one of the three most important features in the horoscope. It symbolizes one's sub-conscious, emotional make-up and needs. Because the moon is not the rational, verbal part of the chart, but rather operates at a "feeling" level, it is difficult to explain it in words.
Poets and even some astrologers have long viewed the moon as inconstant and "fickle" because of its daily change in going through the lunation cycle. Consequently mood-swings are associated with the moon. Ancient observers, however, understood that these changes were orderly and predictable, and therefore could be used in time-keeping. "Moon" and "month" have the same root.
Others stressed the moon's reflectance of the sun's light. Perhaps this seemed like an appropriately female interpretation of the moon in view of the sun interpreted as "the king", yet all of the planets visible to the naked eye or photographic images also reflect light, including the "masculine" planets Mars and Jupiter. Nevertheless as the celestial body that most clearly reflects the sun's light and that most obviously changes form during its cycle, the astrological moon symbolises the receptive principle whose creative act is to receive something and transform it into something new, in the same way that the moon receives the light of the sun and bathes the earth in its silvery mysterious light.
The moon's house and sign show the individual's instinctive emotional reaction without having first been filtered by consciousness. It also stands for the instincts and an individual's need for emotional security.
Children will therefore express their lunar qualities in a more direct manner than adults. The lunar principle is the most important one during an individual's early childhood, and it is only from about the seventh year (or puberty) that the solar principle begins to become more powerful.(See Astrology of Children).
In later life the position of the moon in the horoscope indicates the kind of experiences a person is likely to have had during childhood. It also continues to accompany each individual throughout life as their "inner child".
Karmic astrology considers the moon to be a "vessel for the karmic memories of the soul." There is a long historical tradition of considering the moon as the home of the dead, and the idea of the moon as a "dead" planet continues with some forms of esoteric astrology. The moon symbolises the nocturnal "consciousness" as manifested in dreams, but also in the phase shortly before falling asleep.
The moon symbolizes the feminine principle, particularly its maternal nurturing side, and in an individual's horoscope, the symbol of the person's image of the actual mother. The moon's orbital period may be related to a woman's menstrual cycle, and in a woman's horoscope is, together with Venus, part of her feminine identity. If a woman has children, her moon will indicate her likely attitude to motherhood and her relationship with her children, so that the themes of nurturing and caring are important when interpreting the position of the moon. On a concrete level it also symbolises the actual home environment.
The position of the moon also says something about an individual's physical health due to the effect the emotions have upon the physical body (psychosomatics).
In the horoscope of a nation or politician the moon stands for the populace. In an event chart, however, the moon may act as a trigger, even when planets seemingly more involved in the event are not exact. In a horary chart, the moon symbolizes the querent and its applying aspects are critical to the judgment.
When the moon aspects other planets or a main axis in the natal horoscope, some of their qualities will be reflected in the moon's emotional nature, and vice versa. For example, moon-Mars contacts may indicate "angry feelings." The effects of the moon in transit on a natal chart are usually only felt for a few hours and indicate passing changes in moods. Hard transits of outer planets to the moon can be emotionally trying: for example a moon-Saturn contact may lead to feelings of discouragement. The progressed moon moves relatively quickly and can indicate changing areas of focus in the maturing person's life.
- Theoi Greek Mythology
- The Sun and Moon in Families (Erin Sullivan; excerpt from The Astrology of Family Dynamics. Weiser, 2001)
- Fenton, Sasha, 2009. Sasha Fenton's Moon Signs, revised ed. Zambezi Publishing Ltd.
- Greene, Liz and Sasportas, Howard, 1992. The Luminaries: The Psychology of the Sun and the Moon in the Horoscope, Samuel Weiser, Inc.
- Herring, Amy, 2010. Astrology of the Moon: An Illuminating Journey Through the Signs and Houses, Llewellyn Publications.
- Shakespeare's Juliet entreats Romeo,
"O, swear not by the moon, th' inconstant moon.
That monthly changes in her circle orb.
Lest that thy love prove likewise variable."
- From a 1550 edition of Guido Bonatti's Liber astronomiae.