Meet the Beatles!

  Here’s the opening blog of a quartet.  The theme: giving you a better understanding of the behavior of the most familiar objects in our sky: The Sun, the Moon, the brightest “star”, Venus, and the constellations that make up the zodiac.  First up, though: The Sun.

As with most of my generation, I grew up listening to Beatles music.  “Help!” was the first album my older sister ever bought, and we proceeded to almost wear the vinyl out on her mid-60’s record player.  Surprisingly, though, I never paid much attention to Beatles lyrics; I suppose I thought they were largely nonsensical (though frequently clever) plays on words that John Lennon created for his own amusement.

My inattention to Beatles lyrics extended even to McCartney classics like The Fool on the Hill, even though I think the melody is absolutely gorgeous.   Sing it with me, won’t you?

Day after Day
Alone on a hill
The man with the foolish grin is keeping perfectly still
And nobody wants to know him
They can see that he's just a fool
And he never gives an answer

But the fool on the hill
Sees the sun going down
but the eyes in his head
see the world spinning round....

Ooh, ooh,
Round and round and round and…

Just typical Beatles nonsense, right? Certainly nothing too profound.  At least, that's what I used to think.

But that was before I started what has become almost a weekday ritual in my life.  I happen to live right beside Steven's Creek Trail, which parallels the section of a creek that flows out of the Santa Cruz Mountains and into the south end of San Francisco Bay. Most days after work, I combine walking and running along the trail for about two miles out and back.  The exercise is great, of course, but it also gives me a daily chance to think and ruminate about topics to post on the Whabblog.  

As great good luck would have it, Steven’s Creek (and the trail) is oriented almost exactly north-south, at least along my portion.  That chance alignment means that I’m facing virtually due north during the 20 minutes or so that I’m running away from my place, and virtually due south on the way back.

What does this have to do with "The Fool on the Hill"? Well, the chance alignment of the creek with the Earth's axis affords an extended opportunity for me to visualize things.  Astronomical things, quite often, like the relationship between the Earth and nearby objects like the Sun, Moon, and even Venus. 

The opportunity to visualize comes in handy.  Take the behavior of the Sun, for instance.  Every day, the Sun rises at some point along the eastern horizon (somewhere off to your left, if you stand outside and face due south, like I do while I’m running back to “McCann Manor”).  In a pattern that’s as familiar to us as the back of our hands, the Sun moves steadily across the sky until finally disappearing somewhere off to our right at sunset.  

Of course, intellectually, we all know that the movement of the Sun is just an illusion.  It doesn’t really “rise” in the East, or “move” across the sky, or “set” in the West.   Instead, the Sun’s apparent motion is brought about by the fact that the Earth spins on its axis, completing one full rotation every day.

But it's one thing to SAY that the movement of the sun is an illusion; it's quite another to fully “grok” the reality behind the illusion.  What I mean is, it’s actually quite difficult to square sunrise, sunset, and everything in between with the reality that the Sun doesn’t budge one inch.   To smash the illusion, imagine yourself outside, facing due south, right at sunrise. Imagine further that the Earth is spinning in an easterly direction, which forces you (and everything around you) to move continuously to your left.  Visualize that spin literally forcing the Sun (the stationary object) to move in the opposite direction and track across the sky to the west.  Eventually, the continual steady spin pushes the Sun all the way to the western horizon, and then past it.

Now comes the fun part.  Just because the Sun has set, don’t stop now.   Continue to imagine you rotating in that easterly (leftward) direction.  What effect does the rotation have on the position of the Sun after it sets?

We’ve seen that when the Sun was “up”, your local direction of movement was “pushing” it ever further to the west.  Once the Sun sets sets, though, that leftward spin starts to “pull” the Sun back toward you; that is, it now “pulls” the Sun in the same direction that you’re spinning.  Expressed another way, your rotation is yanking the Sun ever closer to the eastern horizon, with sunrise as the inevitable result.

So you think you have this concept nailed? Here's the ultimate test.  Stay up to about midnight, go outside, and face due south. Then, even thought you can’t see it, point exactly to where the sun is.  If you get it right, you’ll be pointing straight down into the ground below you, at a position roughly aligned with the North-South meridian. If you stayed up later, you'd still be pointing into the ground, but at a location that's starting to slide off to your left.   Are you with me, here?  Stay up even later, and eventually you'd be pointing to a position way to your left, just below the eastern horizon. And, then: presto! The constant eastward spin of the Earth forces the Sun back into view along the eastern horizon, and you’re pointing at the sunrise.

This ability, to imagine where the Sun is and how it behaves at night, is the key to abolishing the illusion of a stationary Earth and a moving Sun.  Of course, you don't actually have to go outside, or wait until midnight (or later) to visualize it. Try, instead, going out right at sunset, the next time the sky is clear, and face south. Then imagine you are suddenly spinning to the left (east) at much faster rate than the speed that the Earth actually rotates. What happens to the Sun?  It’s actually quite easy to imagine it racing around that circle through the ground beneath you, closing in quickly on the point that intersects the location on the eastern horizon where the Sun rises.

And then you'll have done it, patient reader: You'll have matched the observational capabilities of the Fool on the Hill!  Day after day, for the rest of your life, the eyes in YOUR head will see, not a moving ball of fire, but a world (our world) continuously spinning round and round and round. And YOU will have a gut-level understanding of a truth about the relationship between the Earth and the Sun that eluded humankind for almost the entire time that we’ve existed on the planet. 

The form of visualization exercise I’ve asked you to engage in will pay dividends in the rest of the blogs in this series, too.  In the meantime, let’s sit back and appreciate the genius of the Beatles’ lyrics, in addition to their melodies.