Sidereal, Tropical, Age of Aquarius, what does it all mean?
Fun fact: An astrological age is 2160 years, the moon’s diameter is 2160 miles and ages result from the wobble created by the gravitational forces between the sun and moon.
The ages mark the difference between the tropical and sidereal zodiacs. We were in the age of Aries thousands of years ago when astrology emerged into our consciousness and use. It was the most recent time the tropical and sidereal were aligned.
Here’s a run down of what tropical, sidereal, and age mean in astrology.
Tropical Zodiac
In the northern hemisphere the spring equinox marks the first day of spring and the sun’s entrance into Aries. Having this equinox define when the sun enters Aries is the basis for the tropical zodiac.
The tropical zodiac is independent of small changes to the orientation of the earth’s axis caused by gravitational forces between the sun and moon, because each year the vernal equinox equates to zero degrees of Aries.
Sidereal Zodiac
The sidereal zodiac is determined by the current orientation of the earth’s axis. So it shifts over time due to the gravitational forces between the sun and moon. This orientation change makes a complete cycle through the zodiac every 26,000 years. This shift is the difference between tropical and sidereal.
Those of us using a tropical zodiac continue to use the sky map that created the foundation of astrology. The vernal equinox was in Aries when astrology emerged and we continue to assign Aries to the vernal equinox each year.
Those using sidereal are using the current orientation of the earth’s axis so the whole zodiac shifts over time. We call this shift the precession of the equinoxes, as the vernal equinox makes it’s way through the zodiac.
It takes 26,000 years for the equinoxes to move through the zodiac. Divide by 12 and you get 2160 years per sign. A sign equals an age. Each age lasts 2160 years.
Every 26,000 years the tropical and sidereal are aligned (they match).
Astrology Age
We were in the age of Aries when astrology emerged, because the vernal equinox was in Aries. The precession of the equinoxes goes in reverse order of the zodiac, so we went from Aries to Pisces. Next is Aquarius.
There is some debate among astrologers regarding the reference points to use to determine our current age. There is consensus though that we are either in the end of the age of Pieces or just entering the age of Aquarius.
The name tropical zodiac comes from Tropic of Cancer and Tropic of Capricorn.
The tilt of the earth’s axis give us two latitudes, a most northern and most southern, where the earth is directly above the equator. They are called Tropic of Cancer (most northern) and Tropic of Capricorn (most southern).
The seasons on Earth change because the planet is tilted on its axis as it travels around the Sun. This means different points on Earth receive more or less sunlight at different times of year. If the Earth were not tilted, the Sun would always appear to be directly above the Equator, so the amount of daylight at any given place on earth would stay the same and we would not have seasons.
Because we have this tilt, we have seasons and they are marked by equinoxes and solstices.
The equinoxes happen in March and September. These are the days when the Sun is exactly above the Equator, so day and night are the same length. With the solstices, the daylight varies, so they give us the longest and shortest days of the year.
Those two solstices happen in June and December. These are the days when the Sun’s path in the sky is the farthest north or south from the Equator. In the Northern Hemisphere the June solstice is the start of summer, because the North Pole is tilted closest to the Sun and the December solstice is the start of winter because the South Pole is the one tilted towards the sun. That’s why winter and summer are reversed between the US and Australia.