Tuesday, September 25, 2012

The Age of Aquarius

This is the dawning of the Age of Aquarius
The Age of Aquarius
Aquarius! Aquarius!
   James Rado, Gerome Ragni
   In “The Age of Aquarius”

That age, or rather its dawning, may still have some resonance in pop culture—if you’re old enough—and that’s because before we started having “bad hair days” we had Hair, the musical, and it introduced the notion of that age in its most celebrated song, “The Age of Aquarius.” Now the notion that we have celestial or astrological ages derives from the precession of the equinoxes, discussed in my last post. This is an add-on to complete the picture. Yesterday I pointed out that a mismatch has developed between the dates on which astrological “months” begin and the actual constellation showing in the sky on those dates. Thus, yesterday, began the period of Libra, but the sun actually rose in Virgo. The reason for this is because precession has caused the seasons to begin earlier and earlier—but we still observe an astrological year fixed far back in time. The astrological age, however, is determined by actual astronomical observation.

The “age” in which we live, at any one time, is determined by the constellation in the sky as the sun rises on the day of the vernal equinox. This year that took place on March 20, and the sun rose in constellation of Pisces. Therefore, these days, we are in the Age of Pisces. So why is Aquarius dawning? And when will its Aquarian sun actually rise?

Well, our current calendar conveniently begins with the first year of the Age of Pisces. Some put that at year 0, others at January 1, 1 AD. Each age lasts 2,160 years. And while the regions actually covered by the 12 houses of the zodiac are of varying width, by convention they are of the same size, each describing 30 degrees of a circle. Therefore the Age of Aquarius will begin with the vernal equinox of 2160—or if you insist on observing a Year 0,  2161. Now for the math.

The Great Age, meaning the time it takes for our poles to point to the same points in the never-changing sky, lasts for 25,920 years. If we divided that number by 12, we get the time during which each house “rules”—2,160 years. Since each such period covers 30 degrees of the sky, the precession of the equinoxes moves 1 degree every 72 years.

The illustration shows Pisces in the center and part of Aquarius in the lower right corner. I've inserted a little orange sun to inicate where the sun rises these days on the vernal equinox. The movement of the sun, over extended ages, on that date, is from left to right, appearing ever more to the right—but it takes a lifetime for it to cover a single degree of the circle—not perceivable through 76-year-old eyes. The image is from Wikipedia (link).

A geometrically more pleasing presentation comes from Roy Taylor’s “Precession of the Equinoxes” (link). It shows the movement of the Spring and Autumn equinoxes over time on a circle of the sky rendered into equal 30 degree segments, each owned by a house. The first shows the Equinoxes after the Age of Pisces just began thus around 2000 BC, the other the situation around 2005 AD. Are we at the dawn of the Age of Aquarius? Roy Taylor thinks so, and the astronomers bear him out.

Food for poetic contemplation, this. The fish-symbolism is intimately linked to Christianity. When I think of Hair, I think of the New Age. But then, when  I contemplate the precession of the equinoxes, I think to myself: What goes around comes around.

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