Fire and Ice

10 August 2013

The Hairless Star

Imagine if you will a mountain far larger than Everest or K2.  Now imagine that this mountain is made of ice; ice with a leavening of stony debris and dust—gravel and particles of fine grit.  Color it the darkest shade of charcoal, with perhaps a slight reddening, and then lift it into the sky.  If your imagination can reach, place it far from earth—out in the vast spaces beyond the planets, on a curving path that takes it even farther from the faded Sun, a path that will not return it to the warmth of the inner Solar System until the year 2125.

This is Comet 109P/Swift-Tuttle*.  Too far from the heat and light-pressure of the Sun to display tail or even the dusty crown of coma, 109P tumbles through space on the outbound leg of its 133 year-long orbit, naked, dark, invisible against the background stars.  Darkened by uncounted centuries of exposure to Sol’s ultraviolet radiation, it has long-since been lost to sight by Earth-bound observers with even the greatest of telescopes.  Farther and farther from the warm center of our solar neighborhood, Comet 109P journeys alone.  But not forgotten.

Yesterday’s Comet

Comet Swift-Tuttle was probably observed by Chinese astronomers in the first century BC, and certainly it has appeared many times in our skies over the centuries, but it acquired its hyphenated name in July 1862, when independently discovered by Lewis Swift and Horace Parnell Tuttle.  It’s orbit was calculated and soon researchers realized that this “hairy star” had appeared in the heavens before.

Comet 109P is also part of my own history; in the early 1990s I was able to observe its passage through our skies with my portable telescope and binoculars, and so I have a small but definite proprietary feeling regarding this frozen visitor from afar.  It is one of the few dozen comets I have been fortunate enough to view over the forty+ years I’ve been stargazing, beginning with Comet Kohoutek in the early 1970s.

I’ll never see the bloom of coma, the fan-shaped tail of Swift-Tuttle again; my own journey through life is quite short when compared to that of this lonely voyager.  But I will see the orphaned children of 109P, and soon.

The Dusty Trail

Like all active comets, Swift-Tuttle leaves behind pieces of itself as it travels its long orbital track around the Sun.  In the heat and pressure from our star the crust of the comet loses infinitesimal portions of its mass; sublimation of its shell of ice from a solid to gaseous state results in a slow dispersal of its solid mass along the portion of its orbit that crosses the inner solar system, dust and ice particles slowly spreading out along its track and following in the wake of the parent body with only the tiniest of differences in velocity.  Comet 109P has been pursuing nearly the same orbit—with only occasional perturbations caused by the gravities of planets passed along the way—that this slow process has spread the lost mass along the entirety of Swift-Tuttle’s orbit.

Imagine this—not only is the 26-kilometer-across mass of 109P continuing faithfully to follow this well-defined pathway around the Sun, but that same pathway is also inhabited by the debris that the comet has generated over the countless millennia!  The individual orbits of the billions upon billions of particles of dust and icy residue vary slightly, so there is some spreading-out; some are lost forever through perturbation by the giant planets, others simply wander away due to miniscule differences in momentum, and many, many are channeled by gravitational variations into twisted ribbons of matter, invisible streams of dust and ice.  Unseen they rush through space, in general following the orbit of their parent body.  These particles are known to science as Meteoroids.

Tonight’s Meteors

Comet Swift-Tuttle’s orbit is an ellipse that drives deep into the solar neighborhood, and compared to the open vastness of the outer system our warm central region, close to the Sun, is a crowded superhighway of planets and asteroids; it is remotely possible that 109Ps orbit will intersect that of one or more of these bodies at some point.  And when it does…

Now we come to the most wonderful co-incidence of our story; the intersection of one of those ribbons of dust and ice—a meteoroid “stream”—with a planet near and dear to us--Earth.  For the past few weeks our world has been driving deeper into the spread-out debris of Comet 109P, being struck by more and more particles over recent nights, and as I write this we near the central, most dense portion of Swift-Tuttles’ stream.  Because of the same effect of relative motion that makes snowflakes seem to streak toward your windshield from a certain point in the distance, this stream of debris appears to drive toward us from the direction of the constellation Perseus; for this reason we call this collision of planet and meteoroid stream the “Perseid” meteor shower.

When the particles of space debris dive into our planet’s atmosphere they are known as “meteors”; striking the thin upper air at incredibly high speeds they begin to slow, transferring their kinetic energy they heat the surrounding molecules of gas to incandescence.  This is the bright streak you see—a “shooting star”.  The Meteoroid is not “burning up” as much as breaking-up; the increasing air pressure overcomes the objects tensile strength as it shatters into smaller and smaller pieces until—in most cases—only the finest dust remains to sift through the lower atmosphere to the ground.  The rare fragment that makes it intact to the ground is known as a Meteorite.

The Sons of Perseus

The Perseids are one of the years’ most impressive and reliable meteor showers—the “old faithful” of annual celestial fireworks shows.  Each year, beginning in the last week of July and strengthening into the second week of August, the bombardment begins; millions of tiny bits of matter striking our planet’s upper atmosphere.  Most are too faint for us to see; the vast majorities are detectable only by the “hiss” of radio static to be heard on certain frequencies.  Many are seen as quick “shooting stars”, and a tiny fraction—a few thousands—will light up the night sky and draw appreciative gasps from all observers.  To see a bright “fireball”, drawing a green or yellow trail behind it, is one of the most sought-after experiences of the meteor watcher.

The next two nights; 11-12 and 12-13 August, are forecast to be the critical times to observe the Perseids; from a dark location with a wide view of the sky it may be possible to observe 50 to 80 meteors an hour after midnight, and even before that time there should still be a pretty impressive display.  I’d like to invite you all to go out under the August skies and meet the wayward children of Comet 109P Swift-Tuttle; they’ve come a very, very long way. Weather permitting, I’ll be out on deck to greet them.

Tom Epps

Operations Chief

USNS Alan Shepard

Persian Gulf

The Superlative Moon

Hello, Shipmates!
By now I have no doubt that most of you have heard some small part of the “Super Moon” hype—at best you’ve been informed that the Full Moon on Sunday night will appear somewhat larger and brighter than usual, and at worst you’ve been treated to the “doomsday” scenarios that connect the “Super Moon” to floods, earthquakes and bizarre weather around the globe, usually accompanied by “photoshopped” images displaying a Moon of ludicrously impossible apparent size, dominating a skyline.

Here’s one now…

Of course, there is no known relationship between the Moon motions and such disasters, beyond the normal effects of the tidal effect that it has on our planet’s oceans and crust; the Moon will be no closer tomorrow night than it has hundreds of thousands of times in the past, and will have no more effect than usual, with the exception that many, many more people than usual will be out looking at it!

So what is happening here, that our companion world will appear up to 18% larger –and 30% brighter—than a normal, run-of-the-mill Full Moon does each and every month (a measure of time that originates in the orbital period of our natural satellite—perhaps we should call it a “Moonth” instead)? It’s quite simple, actually…the Moon orbits Earth along an elliptical path, taking 29 53 days to complete each journey from New Moon through Waning Crescent, First Quarter, Full, Last Quarter and back to New again. Since its path is an ellipse (above) the distance from Earth to Moon varies considerably during the course of a single obit, with the near-point of it’s path (“Perigee”) being considerably closer to Terra than the far (“Apogee”).

It is on those occasions that the Moon reaches that near point of Perigee at a time close to the Full Moon that a “Super Moon” (the astronomical term for this event is a “Perigee-Syzygy” for the combination of a Perigee with Syzygy, or the alignment of Sun, Earth and Moon) occurs in our skies. Of course the Moon reaches Perigee every month, but the effect of a larger-looking Luna is less obvious when the Moon is a crescent- or Quarter-phase, or especially New. Just as importantly, most people hardly notice those less-brilliant apparitions of our natural satellite; the sight of a Full Moon, however, can stop folks in their tracks!

So plan to get outside tomorrow evening and enjoy the Perigee-Syzygy (THAT name will never catch on!). Try to go to a location with a fairly clear Eastern horizon just about sunset; then you can enjoy the sight of our Moon rising above the trees (or water, buildings, mountains, etc.) and the effect of its brightening as the sky darkens. Print out the attached moon map and see how many lunar features you can identify with your naked eye or with binoculars. Got a digital camera? Try taking several photos using Manual settings, adjusting ISO, focus and exposure to get the best image you can.

And as you gaze at our Moon, think about what you are seeing. You are looking at another world, the only body in the Solar System that we can regularly study without benefit of a telescope, without special filters, and still perceive actual details of its surface. And the only celestial body that bears human footprints—that members of our frail, troubled species have actually walked upon its surface. More than that, without the Moon, it is very possible that we wouldn’t be here to enjoy our view of and to ponder our relationship to it.

So show Luna some respect, and look up more often—you may find that our Moon is always “Super”.

Tom Epps
Operations Chief
USNS Alan Shepard

P.S. Announcing the "Super Moon" photo contest: send me your best picture of Luna, and tell me of your experience…I'll post the best of them here.

The Alan Shepard Observatory

First Light

On the evening of 25 May Alan Shepard’s bridge team watched a lovely spectacle from the bridge; only a few minutes after sunset the members of the watch could see a brilliant point of light about ten degrees above the western horizon. It was quickly joined by a slightly dimmer spark above and to the left of the first, and finally a third gleamed in the hazy twilight, a dazzling triangle of "stars" shining between the clouds.

What we were seeing that evening was a conjunction of three planets; Venus, Jupiter and Mercury. The four of us on the bridge enjoyed the view for nearly a half hour before the three worlds vanished into the dust-laden air of the horizon. They were a brilliant sight through binoculars; I could just fit all three planets into the 5-degree field of view.

I’d been aboard since 14 May, but between the murky skies to be found in the Persian Gulf and the hectic pace of the turnover I was receiving prior to assuming my duties as Ops Chief I’d not had any real opportunity to star-gaze; in astronomical parlance this conjunction of three ‘wanderers’ is known as “first light” for me aboard this ship. I find it quite appropriate, in fact, to commence astronomical observations aboard a vessel named for a Mercury Program astronaut with a sighting of the elusive planet Mercury itself!

Under the Dome

Alan Shepard is not my first sea-going observatory; since 1981 I have (rather selfishly) used nearly thirty vessels as roving platforms for viewing the heavens, staying up long after my assigned duty hours to watch the skies. In fact, the vast majority of the entries in my Observing Journal over the past three-and-a-half decades recount the observation of meteor showers, solar and lunar eclipses, planets, stars and other “deep sky” objects from pitching, rolling decks. Such is the nature of my career @ sea; that I am rarely to be found at home and able to use my telescopes there for their intended purpose of exploring the visible universe.

I have to leave my heavier instruments behind when I come to the sea; my telescopes packed carefully away, eyepieces, tripods and the hundred peripheral parts and pieces boxed and placed into storage. I have learned that in the shipboard environment they would be useless; extra baggage to carry to faraway ports only to languish in a locker, delicate optics and mechanisms risked to no advantage. Long experience has taught me that the best astronomical instrument for this environment is a pair of trusty binoculars; when I travel to meet my newest vessel I carry mine with me; sturdy 10x50 instruments useful for spotting that dhow on the horizon as well as observing the motions of Jupiter’s satellites or studying our own moon’s features.

Starry Night

Yes, my observations are limited but, Ah, the trade-off! Far from land and the light-polluted coastal realm, I am routinely able to see the night sky as few land-dwellers can; with no intrusive city lights to mask the heavens they blaze forth in dizzying splendor, much as our distant ancestors must have seen them in the time before artificial lighting. From Shepard’s deck I can see the Milky Way arcing overhead as no-one in a town can see, the light of its multitudes making as if to drown-out the dimmer stars of the familiar constellations, blurring the lines of Swan, Eagle, Fox and Scorpion.

And between those stars, wonders! Nebulae bright or dark against the background glow of a hundred-billion stellar candles, open clusters with their often oddly regular patterns of stars like strings of pearls, globular clusters blurry and spherical, and the galaxies, distant and often hard to spot, each a stellar “city” in its own right, home to its own multitude. They tease the eye, one moment invisible, the next an obvious spot of cosmic “fuzz”, and then vanishing again.

And still more to see; through my binoculars the classical planets lie within reach. Mercury, Venus, Mars, Jupiter and his moons, Saturn and the far-away ice-worlds of Uranus and Neptune. The brighter asteroids I regularly watch as they silently play amongst their larger cousins, and the comets, slowly following gravity’s summons diving down into the Sun’s warmth before rushing to escape again, dashing back to the outer Solar System as if Sol’s heat had scorched their tail-feathers! They are the leftovers of creation; the flotsam and jetsam of the sky.

The Lights Go Down

This is my world of night, the time and place where I feel most entirely at peace. Deck rolling beneath my feet, wind whistling in the rigging, dolphins splashing and playing in the phosphorescence of the wake. And the sky above, slowly shifting from east to west as the night wears on, Gemini and Auriga setting on the port bow even as Hercules and Lyra rise from the haze on the starboard quarter. Arcturus overhead and Spica due south, paired with Saturn; all old friends to be greeted and admired. A flash of light to the north; a bright meteor has neatly bisected the “scoop” of the Little Dipper, leaving a fading trail of green mist.

Welcome to the Alan Shepard Observatory. I wonder what the night holds for us.

Tom Epps
Operations Chief
USNS Alan Shepard
The Persian Gulf

Changing Course II

USNS Alan Shepherd

"Amateurs talk tactics; professionals talk logistics."
(Military quote attributed to practically every great general who ever lived)

It's a familiar scene; a resupply rendezvous on the open sea between three grey vessels. The replenishment ship takes "tactical control" of the two warships, then directs them to their stations while maintaining a precise course and speed so that the two combatants can orient correctly on the formations' "guide".

Soon heavy wire-rope cables will physically join their hulls and fuel will pulse through massive hoses; all the while the heavy beat of rotor blades fills the air as a heavy-lift helicopter conveys cargo from flight deck to flight deck. Forklifts position enormous "lifts" of palleted cargo for transfer while line-handlers, winch operators, supervising Boatswain's Mates, and helo control officers perform the industrial ballet by which navies are refueled and resupplied at sea.

Puma 06

Puma 06

Puma Vertrep of USS Carter Hall and USS San Antonio

Suddenly the fueling, the cargo transfer are complete; at a signal from the supply ship the small formation disperses as the combat ships separate and "proceed on duties assigned". In minutes they disappear over the horizon on their various missions and the replenishment unit comes about, shaping course for the next rendezvous, the next scheduled event. There are other "customers" out there that need fuel, food, ammunition and mail.

HMAS Toowoomba

PNS Tippu Sultan

Puma 06 and USS San Antonio

Another UNREP completed, another mission accomplished. Such a dance of machinery and people does not happen by accident; as in any complex undertaking the pieces do not fall automatically into their places to make it all "work". The event must be carefully scheduled, coordinated, and plotted days and even weeks in advance to ensure a successful resupply at sea. All the players must understand their roles in the play, all the materiel and equipment must be prepared, tested and staged, and every possible contingency--weather, shipping traffic, mechanical breakdown, and even enemy action--must be prepared for lest the operation fall apart in mid-execution, endangering ships, aircraft, and lives. There must be a solid, universally-agreed-upon, well-briefed plan.

My plan.

The rendezvous with and UNREP of USS Carter Hall and USS San Antonio in the Gulf of Oman a week ago, which the accompanying photos illustrate, was my masterpiece in the older sense of the end of my apprenticeship and the true beginning of my new career as an Operations Chief with Military Sealift Command (MSC). To bring three mighty ships and their crews together with one purpose I had to negotiate with my opposite numbers aboard them; I had to understand their requirements and limitations as well as our own in order to prepare my briefings and plots. I had to consult 'Shepard's Captain, officers and helo crews repeatedly to ensure that the developing concept of operations was workable, and their feedback was invaluable as I trimmed the rough edges from the plan.
Then, with the "customers" on the horizon, I had the duty of actually driving the process, communicating intents and last-minute information and orchestrating the entire event.

The old saying that "No battle plan survives contact with the enemy" could be well applied here; there were minor problems in the execution of the UNREP, and some improvisation was required, but in the end we had an effective, safe transfer of stores and fuel and all objectives were met; I even had the pleasure of receiving a "well done" from our Captain as the party ended.

I'm proud of my accomplishment, and also humbled by it; my "lessons learned" from this particular event fill three pages in my wheelbook, and though the UNREP went off well I am more aware than ever of the responsibility I bear for this and future operations. The learning process has only begun, and I look forward to the challenges to come.

I think that this change of course in my life and career came at just the right time.

Tom Epps
Operations Chief
USNS Alan Shepard

USS Carter Hall

Ready in All Respects for Sea...

Finally, I've received orders...I'm to report in two weeks' time for duty aboard USNS Alan Shepard, T-AKE 3, and I'm quite pleased by this assignment.  Not only is my new ship named for a personal hero of mine, first American to launch into space and fifth to walk on the moon, but she has a great 'rep' in the Fleet.  I've been hoping for several weeks to "score" these orders, and when the folks in the front office told me I had to restrain myself from a celebratory fist-pump!

USNS Alan Shepard seen from USNS Arctic, 2011

I'll be spending most of the next two weeks helping Lucy move our accumulated goods down from New York to Virginia, but already I feel the old excitement.  I'm headed back to sea again, and this ought to be a good one!

Mare Est Vita Mea!

USNS Alan Shepard, 2011

 

The Sea as a Playground

So, you took a cruise.  Knowing the good record of the major cruise lines, chances are that nothing happened save that you wore yourself out on the dance floor and put on three pounds at the buffet.  You enjoyed picturesque vistas of lovely islands and sunsets and lost some but not all of your money in the casino.  You took a thousand digital photos for your loved ones to admire and in general had a terrific time.

Alternatively, your cruise ship had a major engine room fire that caused a general loss of electricity, food and sewage service throughout the vessel, which then drifted dead in the water off the coast of Mexico for several days.  No lights.  No AC.  No toilets.

Or your vessel struck the rocks off a tiny Italian island and rolled onto her beam-ends, drowning dozens of your fellow passengers and leaving you to swim ashore while--apparently--your Captain took more comfortable passage.  Hey, at least she capsized onto the rocks--a few hundred yards further out and she'd have rolled completely over, killing thousands. Including you.

Or a fitting carried away below decks and the entire South Atlantic tried to come in.  By the time you realized that anything was wrong the ship had taken a severe list--and the crew had abandoned ship, leaving one of the entertainment staff to send a distress call and arrange your rescue before the ship herself succumbed. 

Perhaps your great-grandparents also enjoyed a pleasant, tranquil transatlantic voyage.  Or perhaps they didn't... 

Okay, so you signed up for the adventure of a lifetime.  Just remember that not all adventures are pleasant, and that the sea can be a cruel and unforgiving playground.  Those of us who regularly work on great waters know this all too well; a sea voyage can be uncomfortable, unpleasant, and even dangerous, and a ship--no matter how elegant and solid she may seem--is simply a steel shell filled with machinery that can break down, flammable materials ready and willing to combust, stores of food and water that may or may not be of the highest quality, and--lest we forget--many, many representatives of that frail, fickle, and unpredictable herd called humanity.  Many of them in the crew.

There is no such thing as "safety".  It is a myth, a fiction, a phantom that we seek but can never achieve.  We can expend enormous energies in an attempt to make a vessel, an automobile, an airliner more safe, we can in fact go a great distance toward achieving that goal--but we will never, ever fulfill the dream.  People make mistakes.  Ships founder.  Shit happens.

So book your cruise, make sure your passport is up to date, and pack your bags.  Plan on having  a great time aboard that floating hotel.  But make sure you pay attention to the safety briefings, watch carefully as that crewman demonstrates how to fasten your life-jacket, and learn the emergency exits from your assigned deck and common areas.  Do this first; the casino, dining room or cabaret will wait a few minutes.

And if the worst should happen--as has happened before and is statistically certain to happen again--keep calm, make your way to your emergency station, and follow instructions.  Take care of your loved ones and yourself, and do your best to survive while the sea does her best to kill you.

You can always call your lawyer and get interviewed by CNN later.

Caveat Emptor






P.S.  Trust an Old Sailor: NEVER put on a life-jacket inside the "skin" of the ship.  Wait until you get out on deck.  Too many people have been trapped inside a sinking vessel when she rolled over, the deck became the overhead, and their life-jacket buoyantly pinned them to it.

Sailors are meant to be on ships...

Sailors are meant to be on ships,

Ships are meant to be at sea,

And land ain't nothing but a hazard to navigation!

After all of these years I certainly understand the meaning of this saying, oft-repeated in the Fleet.  Life on land is complicated; at sea it becomes simpler, more manageable, comprehensible.  When ashore I have to deal with the traffic on I-64, standing in line at the ATM, the noise of small children in the cinema, and a thousand other complications that arise when I find myself caught up in the "real" world; when sailing these stressors diminish and fade away.

Aboard ship I know my place, I am familiar with my duties and responsibilities, there are few surprises to interrupt the splendid routine of life underway; a life which resembles closely that which Sailors and Mariners have known for many hundreds, even thousands, of years.   The self-contained world of a sea-going vessel has a structure honed and refined over uncounted voyages which, while perhaps not perfected, serves well to maintain her bottled ecosystem, her government, infrastructure and citizenry. 

On the deck of a great gray ship alongside other seafarers, whether in calm or storm, in close-quarters maneuvering with an aircraft carrier or transiting the Strait of Gibraltar, I am at peace.  I'm not a spiritual man by any definition that I know of, and not prone to "new age" ideas, but if there is a place where I am 'centered' or find 'balance', it is out there on the deep sea, where the days' tensions can be wiped away by the sight of a broaching whale, inevitable "personality conflicts" put into perspective by a sunset or sunrise.

I have been ashore since late in February, and confess that the yearning is upon me.  As much as I enjoyed being with Lucy in New York, as much pleasure as walking Delany and enjoying the woods behind our little house gave me, as much as I treasure those nights at the museum where I volunteer, introducing guests to the wonders of the night sky and our own central star--the call of the sea beckons.

I'll be there soon.