Moving parts

Ever take off toward your next errand only to realize you could kill two birds with one stone if you carry something else along? Why birds have to suffer for this metaphor is unclear, but you’ve been there.  Efficiency, effectiveness, high throughput, they come at a price.  But the price for completing several objectives in one trip may be lower than the combined cost of several trips.  The overall accounting might not be so simple as first assumed.  Keeping track of and managing multiple objectives adds a level of difficulty.  Distractions can be deadly (think distracted drivers).  Still we persist; indeed there is often a surreal sense of satisfaction tied to achieving several objectives with the most meager effort.

These notions occurred to me while reflecting on the path of the total solar eclipse headed diagonally across North America next summer. For a bit on August 21, 2017 the moon will pass between us and the sun so as to cast some shadows.  A partial eclipse and the even rarer total eclipse will traipse from South Carolina to Oregon along a path that will enable millions of Americans fairly easy access to this once-in-a-lifetime experience.  A really nice bit of background is available here.

solar-eclipse - smaller

Our principal players.                      picture credit  1/

Reflecting on the predicted pathway stirred a few ponderances: How precise is this prediction? What sort of galactic phenomena might perturb exactly where the total eclipse’s shadow will fall?  And on a personal note… where should I head to take in the show?

A moment’s reflection on the precision question brings back many of the planetary science lessons studied decades ago. The rotation of the earth, orbit of the moon, location of the earth in its progression around the sun (think elliptical orbit).  Something about the moon’s orbit around the earth occurred to me… not a lesson I held onto very well so I did a bit of research.  It matters:

Lunar_perturbation

Stuff I might have learned if I’d been paying attention.     Figure credit 2/

Now the sun itself is moving about within the galaxy, and the Milky Way is tumbling through the greater Universe. Dark matter, black holes, colliding galaxies, gravitational waves, and those pesky asteroids right back here in our own solar system, they’re all moving parts.  The earth’s rotation is slowing ever so, well… slowly.  The continents are drifting about on the surface of the earth, and the guts of the planet are roiling and bubbling about causing magnetic disturbances and volcanic indigestion.  Oh, and butterflies.  Millions of  butterflies.

That we have a pretty complete model of the bigger players among all these moving parts is comforting. I have to imagine the predicted route of total shadow is going to be pretty close to the route that will actually occur.  But in the end there are a bunch of moving parts – and several of the smaller parts are chaotic (not readily predictable).

Notes on accuracy (by someone FAR more knowledgeable than me) can be found here.

I have such confidence in the current level of planetary science that I’ll wager the predicted day of the eclipse, heck even the hour are close enough that if one shows up upon a site with several minutes to spare you won’t miss the couple minutes it will take for the whole shadow to pass. And the human fascination with space being what it is I’ll go further out on a limb and suggest if any of the moving parts I’m aware of (or the undoubted many I’ve completely missed) are to impact the predictions in place today – someone will ferret them out and revise the predictions.  Check your sources again next July.  It probably won’t hurt to make sure your favorite timepiece is properly set.

Now there is the matter of where one might want to set up camp for the observation. August in SC could be intense.  For that matter, August throughout more than a third of the North American transit line can be uncomfortable.  I hear Oregon is nice in August.  Let’s see, who do I know in Oregon?  Pretty short list it turns out.  Well, if knowing someone along the route is a necessary constraint, I suppose I’m lucky enough.  I grew up just a couple miles outside the total eclipse band that is currently predicted for southern Illinois.  I lived in Lincoln Nebraska for a dozen years and it sits right in the path.  Shoot, even Knoxville Tennessee is only a short scoot down I-75 from the path of totality.  Hmmm, I wonder if there’s a country hillside in Roane County Tennessee that could serve as an observation post??  You know, the sort of place where an agrarian or two might hold out when they’re not working for the man.

With so many possible haunts for me to visit with friends and relatives it got me to wondering what it might take to view the eclipse from several sites along the path. Turns out it’s not such a strange wondering.  In 1973 some scientists used the Concorde to fly along the route of a total eclipse to make some measurements.  The Concorde is no longer flying, but there are plenty of other ways to move along at close to Mach 2 so that you could keep the eclipse in view for more than a couple minutes.  Let’s have a peek at the piggy bank.  Nope.  Looks like I’ll be hoping for a sunny day and the company of friends/relatives in just one local.

After running across all these moving parts and planetary science pieces for background to this piece I was out walking the dog Thursday morning early. It was still an hour before dawn and the moon shown quite brightly as we walked.  Gazing on the moon with my new found knowledge about all the various comings and goings of its path I was struck and my sleepy mind happened to imagine I might ask the old Orb if it were aware of all the excitement we humans were anticipating for next summer’s eclipse.  And imagine my surprise as the old feller not only read my mind but answered my thought with another…  Seems the moon really hasn’t done much consideration of its starring role next August.  To explain its lack of caring in the matter it shared with me a line from an epic Dylan tune:

I’ll be so much older then, I’m younger than that now.

Naturally I wanted to make the correction – it had misquoted the verse. But then it came right back to me:

 Oh, so now YOU are going to call ME out about quoting Dylan lyrics?  I seem to recall you waxing about something the smoker said to the chief.

Obviously the moon has an internet account, is a Dylan fan, and has some sense of humor.  Who knew?  And being called out by the moon hurts more than I’d imagined.

1/ This image comes from: http://www.vancitybuzz.com/wp-content/uploads/2014/10/solar-eclipse.png

2/ This figure courtesy Geologician, Homunculus 2 – from English Wikipedia, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=23379433

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