Sunday, May 29, 2016

The Green Flash

The General Hoyt S. Vandenberg steamed southeast at a leisurely eleven knots across the South Atlantic between Ascension Island and South Africa in late September of 1979.  A clear sky, a mild temperature, excellent visibility, and a calm and bright blue sea served as the daily standard in these subequatorial latitudes.  Classified as a range instrumentation vessel, the General Vandenberg conducted vital national defense missions for the federal government.  For this purpose, she carried an army of technicians who worked with a large assortment of electronic gadgets. Most of the crew, myself included, knew little or nothing of what these technicians actually did.  We just sailed the ship for them. 

In the late afternoon one day, several technicians gathered on the outside deck near the starboard bridge wing to watch the Sun set.  The second mate, an older man named George Hebb, stood on the bridge wing, and seeing the technicians gathering, called down to them: “Get some binoculars and watch carefully as the Sun goes down.  The conditions look good today.  You should see the green flash.”

Dumbfounded by this suggestion, they asked George what he was talking about.  He then explained the green flash to them.  In response, they exchanged puzzled expressions with raised eyebrows and laughed at him.  Finally, one of the technicians asked him bluntly, “Have you been drinking?”

“No!!  I have not been drinking!!” thundered the insulted second mate at his skeptical audience.  “What do you take me for?  A Bowery bum?  You guys want to be called scientists and you don’t know how the world works?  Just watch when the Sun sets and you’ll see what I’m talking about!!”

Normally a very congenial and mild mannered man, George Hebb seldom got annoyed. His outburst silenced the “scientists,” however, and they waited and watched the Sun quietly.  Binoculars in hand, I waited and watched, too, as did George on the bridge wing above.  The Sun set slowly, and as predicted, just when the upper limb approached the horizon, the small remaining section of the Sun turned bright green for perhaps two or three seconds.  Then the  Sun set completely, and it was all over.

The assembled technicians had seen the green flash, and so they now believed what the second mate had told them.  Also, they no longer questioned his sobriety.  Vindication!  But their initial reaction on hearing about the green flash was actually quite typical.  Most folks have never heard of the green flash and have never seen it, and as ignorant people often do, they ridicule what they do not know and have not experienced.  Thirty-seven years after this event aboard the General Vandenberg, the green flash has new credibility in the form of a Wikipedia article[1] and YouTube videos[2].  I’ll stand by the simple and straightforward description set down in the American Practical Navigator, however:

As light from the sun passes through the atmosphere, it is refracted.  Since the amount of bending is slightly different for each color, separate images of the sun are formed in each color of the spectrum.  However, the difference is so slight that the effect is not usually noticeable.  At the horizon, where refraction is maximum, the greatest difference, which occurs between violet at one end of the spectrum and red at the other, is about 10 seconds of arc.  At latitudes of the United States, about 0.7 second of time is needed for the sun to change altitude by this amount when it is near the horizon.  The red image, being bent least by refraction, is the first to set and last to rise.  The shorter wave blue and violet colors are scattered most by the atmosphere, giving it its characteristic blue color.  Thus, as the sun sets, the green image may be the last of the colored images to drop out of sight.  If the red, orange, and yellow images are below the horizon, and the blue and violet light is scattered and absorbed, the upper rim of the green image is the only part seen, and the sun appears green.  This is the green flash.

The phenomenon is not observed at each sunrise or sunset, but under suitable conditions is far more common than generally supposed.  Conditions favorable to observation of the green flash are a sharp horizon, clear atmosphere, a temperature inversion, and an attentive observer.  Since these conditions are more frequently met when the horizon is formed by sea than by land, the phenomenon is more common at sea.[3]

I have seen the green flash many times aboard several ships.  Day after day aboard the General Vandenberg in the South Atlantic, the green flash was clearly visible.  Aboard the Rigel and the Waccamaw in the North Atlantic and the Mediterranean, the green flash was a fairly common event.  I’ve never seen it in the Pacific or the Caribbean, though, nor in the far North Atlantic or the North Sea.  But each time the green flash occurs, it is a magnificent sight to behold, however briefly.  The green flash proves the point that:

They that go down to the sea in ships, that do business in great waters;
These see the works of the Lord, and his wonders in the deep (Ps. 107:23-24).

How fortunate my shipmates and I were to repeatedly witness such a spectacle!  Such a simple and small thing—the last sliver of the Sun changing color from orange to green for the last few seconds of its setting.  Then it disappears below the horizon, and the twilight gradually turns into darkness.  This is the daily transition from daylight to nighttime, and the green flash plays a small but significant role in the drama.  The “wonders in the deep” indeed!

After my Merchant Marine career drew to a close, I thought that I would most likely never see the green flash again.  And, in fact, I did not see it for many years.  Then, quite unexpectedly and in a very unlikely place, I did once again enjoy this opportunity.

Miss Patty and I sailed aboard the ferry John H from New London, Connecticut, to Orient Point, Long Island, on Friday, November 1, 2013.  The ship left New London at 5:00pm, when the Sun was low in the western sky.  While the vessel was crossing the eastern end of Long Island Sound, the Sun cast its low altitude light on a scattered collection of altocumulus and stratocumulus clouds.  This illuminated the sky in a wild assortment of vivid blue, yellow, orange, and pink.  It was a truly spectacular sight.  I remained out on deck to watch this display, and to see the Sun set as well.  As the Sun dropped closer to the horizon, I began to wonder if there would be any chance of seeing the green flash.  The conditions looked good for it.  The air was clear, the visibility excellent, the horizon sharp, but somehow Long Island Sound seemed an unlikely place for it.

Nevertheless, I waited and watched as the Sun approached the horizon and started to set.  Even without any green it was still a magnificent and breathtaking sight.  Then, as the upper limb came down closer to the horizon, I looked more carefully, even to the point of eyestrain, hoping but not expecting to see the flash once again.  Finally, it happened.  Small and faint and fast, the green started in the corners and in a second filled the center of the remaining Sun.  Then it all disappeared as the Sun set completely.  It was quite literally a flash.  It lasted at most a second and a half.  The twilight lingered for a while as the now set Sun illuminated the clouds from below the horizon.  This faded gradually as night came over the sea.  When the John H docked in Orient Point at 6:30pm, the sky was fully dark.

The green flash demonstrates a few points above and beyond the laws of physics as they are described in Bowditch.  First, it illustrates the folly of human wisdom.  The technicians aboard the General Vandenberg laughed at a fully competent licensed officer who knew his astronomy, but he had the proverbial last laugh when Nature irrefutably proved him right.  More importantly, this episode proves one of the laws of truth.  If something is true, then it is true even if someone doesn’t believe it; even if no one believes it, it remains true.

Finally, the green flash speaks to us spiritually.  As one of the many beauties of the natural world, it bears mute testimony to the scientific and artistic genius of a divine Creator.  It calls to mind the Psalmist’s famous exclamation, “The heavens declare the glory of God” (Ps. 19:1), a thought that occurs to me often when I gaze skyward.  No mere human could design, let alone create, the world and the universe that we inhabit.  And yet, we are privileged to enjoy this beauty in the same way that we would study the work of a famous artist.  Many such studies of the heavens have been made, and they have yielded extensive scientific knowledge.  Nonetheless, there remains something transcendent and ineffable about this realm.  In the end, perhaps the best we can do is acknowledge as the Prophet did that:

The heavens were opened upon us, and [we] beheld the celestial kingdom of God, and the glory thereof (D&C 137:1).

[1] See
[2] A few of these are very good; many are mediocre; and some are obvious fakes.
[3] Nathaniel Bowditch (original author), American Practical Navigator: An Epitome of Navigation, Volume 1, Washington, DC, Defense Mapping Agency Hydrographic Center, Publication No. 9, 1977, p. 882.  This book has been issued in many editions, revisions, and expansions  since its first publication in 1802, and has served as the standard reference work for Merchant Marine officers throughout its lifetime.  Aboard ship it is referred to simply as “Bowditch.”

Monday, May 2, 2016

A Perfect Night

The Northeast Regional rolled smoothly along the historic Shore Line, the railroad that has connected Boston and New York since the 1850s, in the late afternoon and early evening of Wednesday, April 20, 2016.  I had made this journey many times over the years.  Now I was going once more to visit my aged and infirm parents on Long Island.  I had not expected today’s transit of the Shore Line to be much different from any other’s, but the time of day and the workings of Nature played upon my mind and carried me far out to sea.

The train left Boston in broad daylight at 5:35pm.  Just over an hour later, it came alongside the shore of Greenwich Bay in Chepiwanoxet, Rhode Island.  Turning inland for a spell, it next came along the shore of Fishers Island Sound in Mystic and Noank, Connecticut.  After crossing the Thames River, the train stopped adjacent to the commercial shipping piers and the ferry docks in New London.  Then, rolling westward through Connecticut, the train hugged the shore of Long Island Sound at three of my favorite locations: Niantic Beach, Rocky Neck, and the mouth of the Connecticut River between Old Lyme and Old Saybrook.  In all these spots I gazed seaward, and out of a long standing shipboard habit, I took note of the meteorological conditions. 

The elements of Nature did their work as the Northeast Regional made its westward trek toward New York.  A cloudless blue sky and a clear atmosphere afforded excellent visibility.  The North Shore of Long Island lay clearly discernible across the Sound’s great expanse of dark blue water.  The bright daylight gradually mellowed into a gentle twilight as the Sun moved ever farther to the west.  Finally, the moment of metamorphosis arrived.  The train sailed alongside the sea as the Sun set among the hills of western Connecticut and the full Moon rose from the hills of eastern Connecticut.  Sunset on the port bow and moonrise on the port quarter, I thought, as if I were at sea.

The twilight gradually became night as the Sun dropped farther below the horizon, but the darkness did not become complete.  The Moon in its fullness reflected the Sun’s light and cast it down to the Earth.  It was a supernal sight.  Reacting once again as if I were at sea, I thought of taking stars.  There would of course be the routine of star sights at evening, and later, morning twilight.  But with these outstanding conditions—the cloudless sky, the clear air, the unlimited visibility, and the full Moon to illuminate the horizon—there would be a further opportunity for midnight stars as well.  The conditions were just right.  It would be, for navigational purposes, a perfect night!  The third mate on the 12:00 to 4:00 watch could use this quiet time to practice his craft and perfect his skill by taking sights of Rigel, Betelgeuse, Vega, Capella, Regulus, and the ever stationary Polaris.

These and other celestial luminaries were my best friends in the long hours of many night watches.  I thought back to one transatlantic voyage in particular, aboard the Victoria in the summer of 1981, when the conditions were just right, night after night, for midnight stars.  Dutifully taking up my sextant shortly after the change of the watch, I made the rounds of the heavens and took sights of six or seven stars each night.  I always felt that I was working in communion with Creation itself when I did this.  Alone on the bridge wing of a cargo ship in mid-Atlantic just after midnight, I was always aware of a spiritual persona that emanated from the primal elements of the sea and sky that surrounded me.  In this other-worldly realm, I relied on the absolute infallibility of Nature as I calculated the ship’s position on the trackless sea with mathematical precision.  Afterwards the helmsman always asked me, “Well, mate, are the stars all in their right places tonight?”  I assured him that they were, and that the Victoria was, too.

My thoughts were suddenly brought back to the present when the Northeast Regional rumbled across the long bridge over the Connecticut River.  The Saybrook Lighthouse at Lynde Point, at the mouth of the river, was clearly visible, as were the distant shore lights on Long Island.  The Moon had risen farther and now hung high in the southeast and cast its reflected sunlight earthward.  A beautiful evening on Long Island Sound. 

Across the bridge and now leaving the waterfront behind, the Northeast Regional continued west to its stop in New Haven.  Underway again, it glided through a brightly lit suburban landscape.  Then, unexpectedly and between stations, it eased to a halt in a dark and somewhat wooded area.  The conductor announced that due to track repairs, the train would wait momentarily for the eastbound Acela Express to pass, and then it would cross over to the adjacent track and continue westward.

During this brief interlude the interior lights in the passenger cars shut off.  This left only the dim glow of a few emergency lights, and so it became easier to see outside into the darkness.  The Moon shone in its fullness; otherwise, the sky was black.  But then, as my eyes adjusted to the changed conditions, a single star came into view.  It shone in the south, at perhaps 35 or 40 degrees of elevation.  Once more, I thought of taking midnight stars aboard the Victoria and other ships.  For the few minutes that my train waited in the darkness for the other train to pass, I sat transfixed by the night sky and felt myself again transported seaward under a canopy of celestial bodies.  And it was indeed a perfect night at sea.

All too soon the Acela Express rushed past in the opposite direction, and the Northeast Regional resumed its journey, rolling through the switches and settling onto the adjacent track.  Two more glimpses of salt water remained for me, first in Bridgeport, and finally while crossing the East River between the Bronx and Queens.  Soon after that my voyage reached its conclusion, and I reluctantly disembarked in Penn Station.

But the thought of a perfect night at sea remained with me.  I had passed many such nights aboard many ships.  All these years later, I still think back on them.  Nighttime at sea has a unique beauty and a very different way of touching the human soul.  The night speaks in a subtle manner but asserts that the Master and Chief Engineer of the universe is fully in command of everything.  He is watching over the world and watching over us.  He invites us to commune with him, and we can invite him to commune with us.

One hymn, with two minor modifications, expresses this thought particularly well:

                        Abide with me; ’tis eventide.
                        The day is past and gone;
                        The shadows of the evening fall;
                        The night is coming on.
                        Within my heart a welcome guest,
                        [Aboard my ship] abide.

                        Abide with me; ’tis eventide,
                        And lone will be the night
                        If I cannot commune with thee
                        Nor find in thee my light.
                        The darkness of the world, I fear,
                        Would [on my ship] abide.

                        O Savior, stay this night with me;
                        Behold, ’tis eventide.[1]

At our invitation, “the true Light, which lighteth every man” (John 1:9) will abide with us all night.  The myriad stars of the night sky symbolize this Light and thereby provide spiritual solace as well as navigational accuracy.  They command the navigator’s respect when he takes his sightings and calculates his ship’s location on the vast ocean.  They command the world’s respect always as they represent the ultimate Light.  If we welcome this Light that “shineth in darkness” (John 1:5) as a permanent guest at every eventide, then every night will be a perfect night.

[1] M. Lowrie Hofford, “Abide with Me; ’Tis Eventide,” in Hymns of The Church of Jesus Christ of Latter-day Saints, Salt Lake City: The Church of Jesus Christ of Latter-day Saints, 1985, no. 165.  The original lyrics replaced by the bracketed ones are “Within my home” and “in my home.”