Ordering of the Zodiac
Aries is the first sign of the zodiac and is ruled by the planet Mars, as it is the Sun's alignment with Aries that marks the beginning of spring in the northern hemisphere. The beginning of Aries is not the first day of March as you might expect, but a seemingly unusual day around 21 March. Aries begins around this date for a very good technical reason.
When the Earth rotates on its axis at an angle of 23.45 degree from the plane of the ecloptic, there is the apparetn path of the Sun around the Earth.When the Earth is tilted away from the Sun, in the follow diagram, it presents the southern hemisphere directly to the Sun. This is the case for six months of the year.The rotation of the Earth causes theSun to appear to move east to west, not north to south, So there is no such thing as four seasons in one day . The above diagram shows that one 21 December the Sun is directly above the Tropic of Capricorn (the Sun is in Capricorn) Six hours later, the Sun is still directly above the Tropic of Capricorn.This is as far south as the Sun will ever appear in the sky.
For the next six months, as Earth orbits the Sun, the path of the Sun will move north.Six months later, on 21 June, Earth is on the opposite side of the Sun, and this is as far north as the Sun will go .
Sun's position in the sky changes throughout the year.
Aries begins when the Sun is directly above the equator.Therefore, on 21 September and 21 March night and day are equal,
which is why each of these dates is known as an equinox.On these dates, the Sun is directly above the equator.
The following diagram represents 21 March, which is the vernal or spring equinox in the northern hemisphere, and the natural starting point of the zodiac. The Earth orbits the Sun each year witht the North Pole constantly tilted towards the North Star. Also known as Polaris, this is the brightest star in the constellation Ursa Minor, and is slightly less than one degree from North Pole .
The ancient Babylonians linked the New Year with the spring planting and it was therefore tied closely with the vernal equinox.