ZODIACS

Zodiac denotes an annual cycle of twelve stations along the ecliptic , the apparent path of the sun across the heavens through the constellations that divide the ecliptic into twelve equal zones of celestial longitude . The zodiac is the first known celestial coordinate system. There are two apparently independently-created zodiacs. Babylonian astrology, inherited by Hellenistic and Indian astrology, developed the zodiac of twelve signs familiar in the West. In Chinese astrology, months and years pass through a cycle of twelve animals that imply certain fortunes or misfortunes related to events occurring within those periods. The Chinese zodiac is not linked to constellations.

The etymology of the term zodiac comes from the Latin zodiacus , from the Greek ? ? d?a??? [??????] , meaning "[circle] of animals", derived from ? ? d??? , the diminutive of ? ? ?? "animal". However, the classical Greek zodiac also includes signs (also constellations) that are not represented by animals (e.g., Libra, Virgo, Gemini). Another suggested etymology is that the Greek term is cognate with the Sanskrit sodi , denoting "a path", i.e., the path through which the Sun travels.

The zodiac also means a region of the celestial sphere that includes a band of eight arc degrees above and below the ecliptic, and therefore encompasses the paths of the Moon and the naked eye planets ( Mercury , Venus , Mars , Jupiter , and Saturn ). The classical astronomers called these planets wandering stars to differentiate them from the fixed stars of the celestial sphere (Ptolemy). Astrologers understood the movement of the planets and the Sun through the zodiac as a means of explaining and predicting events on Earth.

HISTORY

By 2,000 BC, the Egyptians and Mesopotamians marked the seasons by the constellations we now call Taurus, Leo, Scorpio, and Aquarius. However, the marking of seasons by constellations may date back to 5,000 BC. [1] The division of the ecliptic into the zodiacal signs originates perhaps in Babylonian (" Chaldean ") astronomy as early as the 1st millennium BC (likely during Median /" Neo-Babylonian " times) (Powell 2004).

The Babylonian calendar assigns each month a constellation, beginning with the position of the Sun at vernal equinox . Babylonian astronomers at some point during the 1st millennium BC divided the ecliptic into twelve equal zones of celestial longitude to create the first known celestial coordinate system; a coordinate system that boasts some advantages over modern systems (such as equatorial coordinate system or ecliptic coordinate system ).