This article focuses on the planetary aspects of the archetypal heavenly fertility goddess. For a more detailed article discussing her specific mythologies, refer to Aphrodite, Ishtar and Ostara, or Virgo - the sign most associated with her (the Greeks called this sign Parthenos, meaning Virgin).
Etymology and Derivatives
Venus is the root of everything from veneration to venereal disease, both of these tracing their origin to Latin veneris, which is also the root of the romantic names for Friday, e.g. French vendredi, as this day is named for her in all major European languages (in the Germanics it is named for Frigg, or Freya, their equivalent of Venus). Friday is the holy day of Islam, comparable to the Jewish Saturday or Christian Sunday.
A Universal Fertility Goddess
In virtually all cultures, from the Pueblo and Maya of the Americas to the Greeks and Egyptians of the Mediterranean, Venus has always been a fertility goddess.
In Ptolemaic times the movements of celestial bodies were studied carefully, and, though they were not properly understood, a somewhat effective predictive system was devised which consisted of "synods" and "epicycles." A synodic year is the amount of time it takes for a given planet (from Gr. planetese, wanderer) to return to its initial position.
For Venus this cycle is 584 days, but because it is an inferior planet it spends roughly 263 days as morning and then as evening star or vice versa, with the remainder spent behind or in front of the Sun during conjunctions. (Be sure to note that this is different from orbit, the time it takes to circle the Sun - which for Venus is 224 days.) This 263-day cycle likely inspired the Mayan Tzolkin, a 260-day calendar which they aligned with the solar Haab (365 days), though the modern Maya themselves maintain that it is derived from maize agricultural cycles; others suggest it may be related to human gestation, which on average is 268 days. The Tzolkin, i.e. the cycles of Venus, determined times of war and peace; the evening star was a positive military omen and wars often began around this point in its cycle.
The average human gestation period of 268 days certainly also accounts for Venus' association with fertility, love and sexuality.
The Flower of Venus
Intriguing mathematical relationships exist between Venus, the Earth and the Sun. For example, for every 5 Venus synods, 8 Earth-years and 13 Venus-years will have passed (5 x 584 = 2,920; 8 x 365 = 2,920; 13 x 224 = 2,912 days): the first 7 numbers of the Fibonacci sequence are 1, 1, 2, 3, 5, 8, and 13. (Their sum is 33, the number of the Perfected Initiate or Solar Christ.)
This relationship means that every 8 years Venus draws a fivefold flower pattern, or pentagram in relation to Earth and the Sun (with either taken as the immobile center). Many argue that mere coincidence is responsible for this agreement with Venus' fivefold symbols, such as the star and the rose, in spite of the fact that ancient astronomers literally based their study on synods.
The fivefold rose is a symbol of both the Rosicrucians and Martin Luther, and the inverted star reveals the Satanic pentagram (see: Lucifer). The Virgin Mary has borrowed a title from Aphrodite, Stella Maris - the Star of the Sea, referring to the planet Venus. Mary is of course the five-petal rose at the heart of the crucifix. (See: Mary; Aphrodite; Virgo)
The difference between the inverted pentagram and the flower of the Queen-Mother is Venus' position in the heavens: the Eastern Star is the 'venerated' while the Western Star is the 'fallen' one. (See: Virgin Mary; Aphrodite; Lucifer)