Aries (astrology) Aries (astrology) Aries (♈) (meaning "ram") is the first astrological sign in the zodiac, spanning the first 30 degrees of celestial longitude (0°≤ <30°). Under the tropical zodiac, the Sun transits this sign from approximately March 20 to April 21 each year. This time duration is exactly the first month of Solar Hijri calendar (Hamal/Farvardin/Wray). The symbol of the ram is based on the Chrysomallus, the flying ram that provided the Golden Fleece. According to the tropical system of astrology, the Sun enters the sign of Aries when it reaches the March equinox, which time systems and the western calendar
Zodiac late Antiquity, by which time Ptolemy's influence was widely established. Ptolemy clearly explained the theoretical basis of the western zodiac as being a tropical coordinate system, by which the zodiac is aligned to the equinoxes and solstices, rather than the visible constellations that bear the same names as the zodiac signs. The Hindu zodiac uses the sidereal coordinate system, which makes reference to the fixed stars. The Tropical zodiac (of Mesopotamian origin) is divided by the intersections of the ecliptic and equator, which shifts in relation to the backdrop of fixed stars at a rate of 1° every 72 years,