I'm continuing to experiment with Glass Bead Pairings -- i.e., interesting possible "moves" in a Glass Bead Game, in which ideas are compared and juxtaposed over a wide spectrum of fields. Before moving on to visualize dozens of luminescent pearls of thought at once, it's nice to start with simple opposing pairs of two.
My GBG mentor, Charles Cameron, once suggested that the SUN and MOON represent two archetypal glass beads that fly across our field of vision every day. Conveniently, they have been made to "stand in" for many contrasting ideas over time, too. Most obviously, the Sun often symbolizes light and heat, and the Moon symbolizes darkness and cold. Western astrologers associate the Sun/Moon dichotomy with concepts of masculinity/femininity, activity/passivity, and constancy/change (although the astronomers may have a valid argument for that last one to be flipped!).
The alchemists associated the Sun with gold and the Moon with silver. It's been pointed out that the relative monetary value of gold to silver has often hovered around a ratio of 13 to 1, and that's close to the ratio of the main cyclic periods of Sun (year) and Moon (month). Causality or coincidence? :-) I'm curious if that analogy extends to copper (the metal of Venus), but I don't know if copper has held such a historically stable value relative to gold or silver...
I could go on with the symbolic associations, but the real thing I wanted to talk about is another piece of trivia: the fact that the Sun and Moon appear to us as very nearly the same size in the sky. The Sun is approximately 400 times bigger than the Moon, but it's also 400 times further away. This nearly exact matching makes total eclipses so spectacular, of course.
I called it trivia. Most people would call it "coincidence." But is it, really?
Let me throw some additional trivia at you. Here are three facts:
- The Sun and Moon have very nearly equal angular sizes in the sky.
- The Sun and Moon have very nearly equal average densities (mass divided by volume). Initially that may seem strange, since one of these things is a million-degree ball of hot gas and the other one is made of rocks... but there you go.
- The Sun and Moon both are responsible for tides on the Earth, and the lunar tides are roughly of equal strength as the solar tides.
Some scientists believe that the presence of tides was crucial for the development of life on Earth. Not only do the tides provide heat -- which may keep the oceans from freezing during ice ages -- but they also transport lots of material to and from the oceans near shorelines. (Rush fans, go listen carefully to the parts about tide pools in Natural Science!) :-) By churning up all this material, the tides may have helped "stir the pot" to bootstrap the very first strands of DNA to start self-replicating.
So what's this have to do with the Sun and Moon? Well, what if there was only one source of tidal pulling? You'd just have a simple, boring sine-wave of tidal motion... up and down, up and down... twice per day as the bulging oceans rotate underneath that single celestial source of tugging. Over a month, the tidal force felt at one point on Earth would look like this:
If both Sun and Moon were present, but with very different tide strengths, it wouldn't look too much different from the above. There would be a weak long-term modulation to that sine wave, but overall it would be pretty much the same.
But we live on a planet where the strengths are roughly equal. What does that look like?
It's certainly not random in any sense, but there's a lot more going on. It's sometimes very strong ("spring tides") and sometimes very weak ("neap tides"). In fact, having two sources of tides with equal strengths maximizes the complexity of these oscillations. My crazy thought is that these ever-changing variations were much more able to spur on (or stir up) the stochastic transport of material that helps natural selection than those dull sine waves above could ever hope to do. And this wild variation was made possible by the same coincidence (?!) that makes the Sun and Moon appear of equal size in our sky.
(Astronomers sometimes talk about the "Goldilocks effect" of our Earth being not too close to the Sun, and not too far away. This could be a different, but possibly equally important, kind of Goldilocks effect!)
So the next time someone asks why we're here? Just point up at those two luminous glass beads...