Wednesday, August 23, 2017

Eclipse

The scientist in me will discard the notion that the stars, planets or infinitesimal planetoids have anything to do with guiding my life, beyond the "butterfly effect".  However, as a human I can't help but notice how celestial events help us to solidify memory and stir reflection.  I can feel the cold and hear the gasp of my 4-year old son when he first sighted Comet Hale-Bopp with his binoculars.  We mark our lives by the return of the Earth to the same position it was on significant days: birthdays; wedding anniversaries; death anniversaries; work anniversaries; commemoration of other significant events; and holidays.  Our nearest star, the Sun, is the ultimate source of energy for life on Earth and a threat to our existence (for example cosmic rays; coronal mass ejections; gamma ray bursts).  We tend to wake with the Sun and sleep in the dark.  Inability to perceive light or working odd hours throws our body clocks into a frenzies such as non-24 sleep-wake disorder.


Beginning of partial solar eclipse 23 October 2014. Photographed
at Park University.The last three solar eclipses have been obscured
by clouds in NW MO
An eclipse occurs when one celestial body casts its shadow onto another.  A lunar eclipse occurs when the Moon passes through the shadow of the Earth.  A solar eclipse occurs when the shadow of the Moon passes over the face of the Earth, apparently obscuring the disc of the Sun.  Eclipses are actually fairly common occurrences as viewed from SOMEPLACE on Earth, but rare in any ONE location on Earth.  You can expect to experience a solar eclipse in any one place on earth every 360ish years, on average.  Most of these events come and go with very little attention from the general populace.

Every now and again, one catches the public imagination.  These are usually total solar eclipses, since it is possible to look at the Sun without risking injury only during totality.  In the center of the path of totality, the sky will darken enough to see the atmosphere of the Sun (corona), planets and stars.  Diurnal animals will seek nighttime refuge and nocturnal animals will start to come out.  As the solar output dims, shadows change accompanied by a palpable cooling.  It is something that is totally out of the ordinary, and novelty sells.


Filtered view of the Sun
This is the experience being sold across the United States since at least 2015.  An eclipse with totality lasting about two and a half minutes.  The width of the total eclipse path in 2017 is about 70 miles and passes across the United States in a southeastward direction from the Pacific Coast of Oregon to the Atlantic Coast of South Carolina.  Some degree of partial eclipse is visible for thousands of miles on either side of the line of totality.  People from all parts of the world descended on little towns all across the United States.  Populations of areas along the path of totality typically doubled overnight.  Sales of all kinds of memorabilia were through the roof: branded eclipse glasses, t-shirts, posters, festivals...etc.

Take time to experience the world now, for you are a long-time dead


Setting up the camera to photograph the eclipse
One thing is for certain about almost any event that strikes a chord with a broad audience: that event will be over-hyped.  Especially if there is a dollar to be made.  While many experienced amusement at the hype, some individuals (even in the popular media) were openly disdainful of anyone that thought this was an interesting event.  There are always the contrarians, those who will go against popular sentiment just because.  There are those that are contrarians because it sells or is fashionable.  If you are not fascinated with eclipses, there is nothing that I can say to you to change your mind, and I won't try.  You have no sense of wonder about the natural world.

I don't have to convince my friend Ed, from Red Wing, Minnesota.  We have both recently lost close friends who were way too young to die.  Knowing that life is fleeting and wanting to experience the spectacle of a total solar eclipse, Ed hopped on a motorcycle with his daughter Marley and staged overnight looking for a break in the weather.  He ended up at the American Legion in Amazonia, Missouri.  Even though the clouds hid totality, he gave the eclipse a thumbs up.  I have some amazing friends.


Darkness falls on Park University as totality nears
There is a stark beauty to a rapidly changing natural canvas - a fantastic out-of-placeness.  More than that, I revel in the accomplishment of thinkers that can record and eke out complex patterns from data 2,500 years before the computer was a thing.  The Babylonians could predict within about 4 hours, when an eclipse would happen, somewhere on Earth.  Edmund Halley would further refine the ability to predict when AND where eclipses would happen.  The ability to predict the occurrence and extent of an eclipse to within a second of precision is a gigantic accomplishment.  Without understanding celestial mechanics and without computers, Babylonian astronomers could pull an astonishingly convoluted pattern out of a big data pile recorded in cuneiform on clay tablets.  It's all Greek to me.


A picture of my friend Ed and his daughter riding from MN to see the
eclipse in MO, taken by Marley and  thieved by me from Facebook
It is only during eclipse that we can really image the corona of the sun - which is key to predicting phenomena such as coronal mass ejections.  An eruption of mass from the Sun aimed at the Earth could bombard us with charged particles and x-rays that would fry our satellites, brick our electronics and destroy the electrical grid.  We got a very little taste of that on 13 March 1989, when a mass ejection hit Earth, causing a widespread blackout in Quebec, Canada.  Understanding space weather is paramount to maintaining our creature comforts, if not our very survival.

Observation of lunar eclipses made by Aristotle allowed him to conclusively state that the Earth is spherical.  He knew from projections of shadows from various geometric figures that a shadow with a rounded edge (such as that of the Earth onto the Moon) could only be produced by a sphere (suck it, Flat-Earthers).  Observations of solar eclipses revealing Bailey's Beads gave us our first indication that the Moon had mountains and valleys.  Eclipses are important because of what we can learn about Earth and its neighbors right here in the comfort of Spaceship Earth.





All That is Now

The eclipse begins
The much ballyhooed Great American Total Solar Eclipse of 2017 arrived to partially cloudy skies at 11:41:06 AM on 21 August in front of Mackay Hall of Park University in Parkville, MO.  The initial obscuration of the Sun's disc by the Moon occurred at about one-o'clock (30 degrees right of straight up).  Lunch was served on the Chapel Lawn, eclipse glasses were passed out and people dispersed over campus to view at various places.  I set up in front of the first building erected on the current campus on a solid, level surface.


Our last glimpse of the Sun in eclipse 21 August 2017
Good views of the eclipse were had all of the way up to the verge of totality.  As more of the Sun's light was blocked out, the shadows got longer, much like a winter's day.  Nadienne noticed that the butterflies had left the flower planters and I noticed that the mosquitoes were biting.  We all noticed that the cicadas started buzzing. About 10 minutes from totality the clouds became heavier, making it almost impossible to see the sun while wearing eclipse glasses or using solar filters, at times.  The clouds totally obscured any view of the sun at about 90 seconds before totality.  In the end, we were about 10 miles too far west.  The clouds held off for a long while to the east.  When totality occurred at about 1:07 PM, we were unable to see anything excepting clouds, but the skies darkened to twilight conditions and lights came on. 

After about a minute of darkness, it lightened up briefly.  Then it started lightning and thundering and the skies opened up, pouring down rain.  The deluge caused flash floods, water overtopped bridges and roads, and Mirror Lake reappeared at the National golf course.  In a time lacking technological savvy, this event would have been recorded with wonder as a Wrath of God event.





Sometimes you use Plan 9


Clouds over St. Joseph, MO on eclipse day
You can predict eclipses and they will come and go on time.  You can predict the weather, but can't do anything about it.  The weather leading up to the eclipse was beautiful.  Nadienne and I enjoyed a nice drive along the path of the eclipse through northeast Kansas and southeast Nebraska on Saturday.  Nearly every community had some kind of viewing area set up or even a festival of some kind taking place.  I had scoped out the yard, figuring where the sun was going to be and making sure I knew how to use the solar filter with my camera.  I bought a 12-pack of Leinenkugel Summer Shandy to enjoy while I took pictures in my backyard - right down the center of the path of totality.

When morning broke, the view outside was dismal.  Hardly a hint of blue in the sky.  The eclipse weather was definitely going to suck.  After checking around for weather, we decided to head to Parkville, which was just at the edge of the path of totality.  We'd get about 60 seconds, but it was better than seeing nothing.


Here comes the Sun!  You can't see a thing with
eclipse glasses on!
Then the clouds rolled in while we waited for the eclipse.  The kick in the teeth came as it started to rain.  Dejected, I nearly got in the car and rolled back home to St. Joseph, halted only by the memory of the parking lot that was traffic from Platte City to St. Joseph.  Not really seeing anything good on the cloud map, we decided to stay put and watch a live stream using on the projectors in a lecture room.  Less than a half hour before things got interesting, a break in the clouds appeared and held off long enough for us to see about 49% of the eclipse. Right before totality, thick clouds blocked our view: eclipsis interruptus.  We were clock (and cloud) blocked.  This just proved my theory of life: Always expect the worst - that way you are never disappointed.  If things go badly, you expected it - no disappointment.  If things go well - it's a bonus - no disappointment.  We didn't get to see totality, but we didn't expect to see anything at all - WIN!


And All That is Gone

Start of lunar eclipse 27 September 2015 viewed in St. Joseph, MO
I saw my first eclipse on the 9th-10th of February 1971 in Honolulu, Hawaii.  My Mom woke me up at night, which was weird.  Even stranger was that she wanted me to go outside and look at the Moon.  As we watched, a rounded edge of darkness crept across the face of the Moon.  What the heck was that?  Then Mom told me it was an eclipse.  We watched to totality, when the moon brightened up to a coppery color.  As the Moon began to reappear, I went back in the house to bed.  A local TV station was broadcasting the event - something that is difficult to find unless you stream it over the Internet.


On the night of 25 May 1975, I was sitting at a picnic table outside of our camper in Minnesota waiting for the moon to go into eclipse.  I had found the dates of the eclipses that would be visible to me for the next few years, and was waiting for this one. This time it was my Dad that came outside and watched with me as the Moon was blotted out by the Earth's shadow and then became an intense, angry red as it passed through totality.

I cut class for the first time on 26 February 1979.  The nefarious reason?  To see the solar eclipse that was occurring that day.  While St. Joseph, MO was not in the path of totality, we would be able to see the Sun eclipsed about 85%.  The event did not generate a lot of buzz and our school administration held no viewing parties.   I made my pinhole projector, asked to be excused to the library (which had windows facing the Sun) to do research for a paper, and sat through a few classes to watch as the light dimmed perceptively and then brightened up as the Moon slid over and past our view of the sun.  I did research for a paper all right, just not the one that was currently assigned to me.



Crescent Sun peeking through the clouds
On 10 May 1994, an annular eclipse sorely tested a marriage.  An annular eclipse occurs when the Moon is just far enough away from the Earth in its elliptical orbit that it can't quite obscure the disc of the Sun, resulting in a dark center with a light edge.  The day was very cloudy in Keego Harbor, MI that day.  Just as the eclipse hit annularity, a break in the clouds occurred and through the haze came a filtered image of this ring of sunlight around the Moon.  I asked Nadienne to get my camera, and between us we managed to drop it, shattering it into several pieces and exposing all of the film that had been in it.  The perfect picture...shot to hell.

I have observed close to 20 lunar eclipses and 6 solar eclipses.  Each one is locked away in memory.  I can close my eyes and see, hear and smell what that day or night was like.  What I was looking forward to, what the last and next disappointment would be.  This was my first real chance to see a total eclipse of the Sun, but the weather nicked me by 90 seconds and 10 miles.  Better luck next time.


And All That's to Come

The next lunar eclipse will come soon - a total lunar eclipse will occur the morning of 21 January 2018 and the setting moon will be in total eclipse as viewed from northwest Missouri.  The next North American solar eclipse will be an annular eclipse on 14 October 2023.  The next Great North American Total Solar Eclipse will be on 08 April 2024.  You will find me somewhere on the path from Dallas to Little Rock to Carbondale to Indianapolis to Cleveland to Niagara Falls (Niagara Falls?  Slowly I turned....).  Book your seats now, seven years is sooner than you think.


Great American Eclipse figure for 2024
Solar eclipses are due to a string of coincidences.  We have a moon, the orbital path of which crosses a path directly between us and the Sun from time to time during the new moon, throwing the Moon's shadow onto Earth.  The disc of the Sun is 400 times as large as that of the Moon, but the Moon is almost exactly 400 times closer to Earth than is the Sun.  This geometry makes it possible for the disc of the Moon to totally block out the disc of the Sun, especially if eclipse happens close to perigee (when the Moon is closest to Earth).  If the eclipse happens close to apogee, the increased distance between Earth and Moon decreases the apparent size of the Moon's disc just enough that the Moon cannot totally cover the Sun's disc, resulting in an annular eclipse. 
  
NASA figure of solar eclipse configuration

The force interactions between the Moon and Earth result in the Moon acting like a brake on the Earth.  As the rotation of the Earth slows, the momentum change causes the Moon to slip a little bit further away.  The rate of change in the Earth's daily rotation slows down by about 4 hours every billion years and the distance to the Moon increases by about 3.78 centimeters per year.  In 1.2 billion years (give or take an hour), the Moon will be distant enough from us that its apparent size will always be smaller than that of the Sun - and eclipses will be a thing of the past, replace by transits of the Moon across the Sun's disc.

And Everything Under the Sun is in Tune




I'm being followed by a Moon shadow, Moon shadow, Moon shadow

But the Sun is Eclipsed by the Moon

This time I was armed with a DSLR camera, telephoto lens and eclipse filter, courtesy of Nadienne, Breena and Christian in all.  Thanks to Randy for the film!
Composite view of Sun during eclipse 21 August 2017

And all that is now
And all that is gone
And all that's to come
And everything under the sun is in tune
But the sun is eclipsed by the moon.

Pink Floyd - "Eclipse"