Platonic Year
Synonym: Great Year
Term for the longest cosmic cycle from a geocentric point of view. It is the time taken for the vernal equinox to travel through the whole ecliptic. This takes 25729 years (according to some estimates 25771 years).
The vernal equinox spends on average 2144 years in one sign of the zodiac. This epoch is known as a Platonic month. A Platonic day is roughly 72 years, the average age of a human being.
Many astrologers believe that the passage of the vernal equinox through one constellation of the sidereal zodiac sets the general tone for a 2000 year period known as an Astrological Age. Because it is not possible to precisely define the sidereal zodiac in relation to the Celestial Sphere, it is difficult to calculate the starting date of a new astrological age. With such long periods of time it probably makes sense to include fairly long transitional phases, from anywhere between decades to centuries. Many supporters of the New Age theory believe that we are currently experiencing the transitional phase between the outgoing age of Pisces and the coming age of Aquarius.
