‘Oumuamua!

Astronomers suspect that the recently discovered object 1I/2017 U1 has been crossing interstellar space for hundreds of millions of years. It comes from the direction of the bright star Vega in the constellation Lyra. However, given its tremendous speed of 95,000 km/hr, it would have passed the point where Vega is now some 300,000 years ago. As Vega was nowhere near its current position in space at that time our Sun may be the first star it has encountered in a very, very long time.

The scales of time and distance stagger the imagination. Where did this lonely wanderer originate and what titanic forces caused it to be nudged away from its parent star…wherever that object might be? Arriving from afar this surprise visitor speaks of time, wonder, age, and mystery. It embodies, in a sense, what many feel when they look up at the night sky. Indeed, the Hawaiian name bestowed upon 1I/2017 U1 by its discoverers captures this sense of wonder perfectly. They call the object ‘Oumuamua which means “a messenger from afar that arrives first.”

Oumuamua
An artist’s impression of 1I/2017 U1 or ‘Oumuamua. Credit: ESO/M. Kornmesser

Given its speed astronomers did not have much time to track this object. By the time it was discovered it had already passed its trajectory’s closest point to the Sun. As it receded light would drop off quickly and so would the ability to gather useful observations. Discovered on October 19th by the Pan-STARRS 1 telescope in Hawaii, astronomers there plotted its orbit over the course of several nights and it quickly became apparent that the new object was passing through our neighborhood from somewhere beyond the Solar System. This exciting initial report was quickly followed by additional observations from astronomers all around the world.

The Very Large Telescope at the European Southern Observatory was quick to spring into action. Located at Cerro Paranal high in the Atacama Desert of northern Chile the VLT consists of four identical, 8-meter wide telescopes. These telescopes can be positioned to serve as an interferometer in which the distance between them makes for an even larger instrument. These were used across several nights to observe 1I/2017 U1.

The details of this observation campaign were revealed yesterday in an article in the journal NatureThe investigators found many surprises and some confirmations regarding what was once considered a hypothetical scenario regarding extrasolar objects. The visitor swept quite close to the Sun at just a little under 40 million kilometers. This is roughly one-quarter of the Earth’s distance from the Sun. In astronomical distances this was just a little inside the distance that the planet Mercury orbits, although at a much steeper angle compared with the ecliptic plane.

'Oumuamua
‘Oumuamua’s path through the our solar system. It is travelling at 95,000 km/hr.

What is interesting about this close pass is that ‘Oumuamua seems to be purely asteroidal in nature, with no behavior or evident out-gassing as might be displayed by a comet. Indeed, a comet passing so close to the Sun would have developed both coma and tail as volatiles on its surface sublimated before the Sun’s heat. ‘Oumuamua appears to be a large, rocky object with a high metal content. Spectroscopic observations show its surface to be ruddy in hue and that is suggestive of organic molecules. This is similar to the surface of many asteroids found in the Solar System.

‘Oumuamua has a “day” that lasts about seven hours. This was noted by measuring a light curve that showed a variation in the intensity of reflected sunlight. That change in brightness varies by an order of magnitude (10x) every seven hours. This weird light curve is not seen in local asteroids, and is suggestive that ‘Oumuamua is quite elongated, almost like a long rugged column of rock.

Other measurements showed few if any traces of dust or ice on the surface. This is indicative of great age as surface compounds were likely swept away by irradiation and cosmic particle bombardment across millions of years. It is also an extremely dark object. Unlike local asteroids ‘Oumuamua absorbs almost 96% of the light that strikes its surface. The visitor is extremely elongated and has an average radius of 100 meters and is thought to be at least 400 meters in length.

An important revelation regarding ‘Oumuamua is that given the fact that it is the first asteroid to be identified as having formed around an alien (albeit unknown) star, it can serve as a model to test a number of theories regarding planetary formation models. In a sense this visitor provides us a sample of material from another star system. Observations and analysis of the new data indicate that it is in many ways similar to some asteroids in our own neighborhood. This is of special note. It helps confirm the idea that planetary compositions as we know them in our solar system could be similar to others throughout the galaxy. Given that there are organic compounds on Oumuamua ‘s surface, the concept that these materials are passed from star system to star system across eons has also been strengthened.

In the last few weeks the estimate for the number of interstellar asteroids that might pass through our solar system has been revised upward. One study has suggested that as many as 1000 objects might fly by our home star every year. That equates to over three per day either entering near-space or departing. Like ‘Oumuamua these objects would have speeds which would make it impossible for the Sun’s gravity to ever capture them.

It is intriguing to think that so many objects with exotic, extrasolar origins might be passing through our solar system. Astronomers are already calling for new observation campaigns and improved instruments to observe such objects. Although Oumuamua might be the first observed and recorded messenger to arrive from afar, it certainly may not be the last.

'Oumuamua
Telescope image of ‘Oumuamua when it was over 50 million kilometers from Earth. Oumuamua is the faint dot in the red cross-hairs. At this point the interstellar asteroid had a relative magnitude, or brightness, of 20+. This extremely faint object was captured in this image by the 40-cm Tenagra III telescope at the Tenagra Observatory (VTP) in Rio Rico, Arizona. Credit: Gianluca Masi (Virtual Telescope Project) and Michael Schwartz (Tenagra Observatory)
Advertisements

The November Queen

Cassiopeia is a well-known constellation in the northern sky. She is surrounded by myth, legend, and, more recently, scientific fact. Writing around 150 AD, Ptolemy, in his Almagest, listed the beautiful queen as one of the 48 known constellations. But over millenia humans have known her under many separate guises.

Since time immemorial the Lapps have seen the asterism as a reindeer or even an elk’s antlers. To the ancient Celts of the British isles the constellation was the mother goddess Anu. Chinese astronomers saw the constellation as a bridge for kings. And when bridges became passé it was suddenly a race chariot wherein one of the stars was the tip of the charioteer’s whip.

Arab tribes called it The Camel. This name makes an abundance of sense and is rather sublime if you imagine the constellation serving as a guide to many camel-powered desert caravans. Later, in ancient Persia, the astronomer Abd al-Rahman al-Sufi drew this constellation as a queen on a throne holding a scepter topped with a crescent moon. Indeed, the names Caph, Schedar, Ruchbah, and Segin mark the brightest stars in Cassiopeia. These are Arabic names and first appeared in many astronomy texts from that 9th-century powerhouse of learning in Baghdad, the Bayt al-Hikma, or House of Wisdom.

Cassiopeia was certainly known to early seafarers of the Mediterranean. And you can imagine the Argonauts or Odysseus’s crew or even the lonely heroes in Virgil’s epic The Aeniad seeing it from the timber decks of their ships. Elsewhere, far away in time and language and distance the peoples of the Marshall Islands in the Pacific saw the constellation and imagined it to be another great seafarer: the porpoise.

RBA_Cassiopeia_1024_Labeled
Image of Cassiopeia with “W” asterism overlaid

The five brightest stars of Cassiopeia have been designated Alpha, Beta, Gamma, Delta, and Epsilon Cassiopeiae. This convention was formalized in the 1920s by the International Astronomical Union. On star maps and within sky atlases the 5 brightest stars and a host of smaller dots and objects are designated as “Cas.” Even when crowded by other objects stars Alpha through Epsilon Cas clearly form the characteristic W-shape that so many budding observers quickly learn.

Four of the brightest stars are within 100 light-years of Earth while the fifth, Epsilon-Cas, is over 400 light-years away. The light we now see from this star left Epsilon-Cas when Galileo and Giordano Bruno were alive in the late 1590s. Despite its distance Epsilon-Cas is as bright as the nearer stars in this constellation due to its massive size. It is one of a class of stars called Be-stars. These stars have weird emissions in which hydrogen lines occasionally peek out when seen on a spectrograph. The lines are shifted due to the star’s rapid rotation. This rapid rotation flings disks of stellar material from the star’s surface. The funny emissions come from the ejected debris and not the star’s surface. It is why the emission lines, which so puzzled astronomers, are highly intermittent.

A bright new star appeared in Cassiopeia in November of 1572. This supernova sits some 8000 light-years from Earth. It was reported by a variety of heaven-watchers around the world. In China the new Wanli Emperor, the extremely young Zhu Yijun, was warned by court astrologers to modify his errant behavior. The new star was, after all, an evil omen. As to whatever mischief the ten year old emperor was involved in remains lost to time and long-lost archives. In England, Queen Elizabeth, concerned about the new star, consulted the mathematician Thomas Allen as to what was happening with the distant queen of the night sky.

More famously Tycho Brahe observed the supernova and documented his findings in a book called De Nova et Nullius aevi Memoria Prius visa Stella or Concerning the Star, New and Never before Seen in the Life or Memory of Anyone. Published in 1573 the book detailed Tycho’s observations as well as many other European observers. Johannes Kepler eventually oversaw publication of later editions.

The remnant of this supernova is today called SN 1572. It has been observed in both X-ray and radio. A shell of gas and debris is still expanding away from the star at 9,000 km/s. There is also a report in the last decade that SN 1572 may have had a companion star. If so, then the supernova of 1572 was a Type Ia, in which the star that creates the event is a white dwarf star. This is important as the white dwarf would capture material from a companion star until the Chandrasekhar limit is reached. This limit is the maximum mass at which a white dwarf star will be stable. Once it is exceeded the star will explode.

SN 1572’s companion star is relatively nearby and has a velocity and behavior that suggests it was effected by the blast. Astronomers call this companion Tycho G. Curiously it is a G2 star not unlike our Sun. However, at the time of the explosion it was probably a sub-giant that readily gave up material to the nearby white dwarf. When the supernova happened the star’s outer shells of matter were shock-heated by the tremendous energy of the supernova. Battered and stripped by the explosion, astronomers have observed that Tycho G’s current velocity is four times faster than anything else in its vicinity. It was likely given a huge push when its companion exploded.

SN 1572 has often been called Tycho’s Star or Tycho’s supernova. Tycho did much of his work on the tiny island of Hven that sits in the Oresund Strait between Sweden and Denmark. Today if you catch the ferry to the island you can visit Tycho’s Star, or at least its namesake. A distillery on the island recently announced a new whiskey which they are calling Tycho’s Star. Perhaps the old astronomer, known for his revelries, would have approved.

 

 

Dia de los Muertos: Another Time, Another Place

Callisto is a dead world…but I’ve been thinking a lot about it lately.

It was just last year at the International Astronomical Conference in Mexico that Elon Musk announced plans to colonize Mars. Those plans continue to unfold with various technical details being worked out so that they eventually align with a workable reality. One thing I recall about Mr. Musk’s presentation was a side note that the ship his team was designing might be capable of travelling to the moons of Jupiter. The presentation included an image of one of the gleaming SpaceX interplanetary ships sitting on a frozen plain of the moon Europa. That was intriguing but I started to wonder whether Europa was the best target for human exploration. There is another alternative. That minor world is called Callisto.

The fourth moon of Jupiter was one of four discovered by Galileo Galilei in January of 1610. It sits some 1.8 million kilometers from Jupiter and orbits its parent body once in approximately seven days.  This world is a place trapped and frozen like a snapshot in time. The tidal flexing that impacts Jupiter’s three inner moons is less powerful here. And very little heat lurks below Callisto’s surface. Thus, not much changes on its mottled dark and light surface. Indeed, it is believed that Callisto’s features have changed very little across billions of years. The biggest upheavals come with the occasional asteroid or meteor impact. Otherwise, Callisto’s topography is subject to the slow, patient gnawing of crater walls and rilles by the process of sublimation. Ices and other volatiles slowly out-gas, leaving only rock or the occasional slump of gravel and dust. Callisto is a tomb, but astronomers use it as a baseline for what other moons eventually become. It is a starting point in the study of planetary formation, and an important one.

One attractive thing about Callisto in terms of human exploration is that given its distance from Jupiter it has relatively low radiation levels compared to Europa. Callisto could be visited, with proper safeguards, by a human crew. This would be important, particularly as any initial visit might require an extended stay. In addition, certain resources, such as ices, could be safely gathered from the surface for air, water, and fuel. The dead world could offer a safe harbor for our kind of life. it could also serve as a base for wider exploration of the Jupiter system.

Six spacecraft have imaged Callisto, with five of those merely passing through the system. On one of the Voyager encounters in 1979 a planetologist described Callisto as looking like a cantaloupe. With those early snapshots false-colored to show geological morphology, Callisto certainly did look like that garden fruit! Another thing that was marveled at was how static the surface seemed. Little, the scientists judged, had changed on Callisto in a very, very long time. Compared to volcanic Io and icy Europa, Callisto seemed dead.

Perhaps when the first human explorers visit they might time their arrival to coincide with Dia de los Muertos. That might be fitting. Those voyagers will surely represent many cultures and nations with no few Spanish speakers among them. Who knows, in honor of a long-ago planetologist they might even share a cantaloupe after the feet of their ship touch down on that mysterious surface. Maybe it will go something like this:

“…dos, uno, cero!”

Their descent to the world of ice and stone began with a symbol of conquest: fire. The ship had enough moondust in its tanks to take them around the solar system at least thrice more. As such a caprice was beyond question they spent fuel extravagantly. This tilted orbit and allowed them to drop down onto the new world from somewhere beyond the horizon of its tumbledown northern pole.

That burn went on and on.

In the cockpit and below decks they felt it as a deep resonance in the chest and bones. Gravity grew. Shadows shifted. Callisto’s terminator turned in cadence with the dozen or so attitude gauges that fought for space on cramped control boards. Even at a high altitude the ship’s mighty engine cast a linear smear of light across the scarred surface below. They were intruders here and a billion years of silence was no easy thing to disturb. Beyond the thick triangular viewports, Jupiter’s Great Red Spot glared balefully down upon the fragile craft from Earth…

Somewhere, a prayer was uttered…

…distance closed and vectors narrowed. The land below was a series of folds and uplifts. Circular craters and curved ridgelines marked where the cosmos had once smote Callisto with iron fists. The terrain was a chaos of crags and cirques and a human’s eye might get lost amid the jumble. Not so Vagabond’s antikytherae. Those computers marked time down to atomic scintillations. The flight was adjusted to match the unknowns of changing topology with the hard data provided by the ship’s instrumentation. Scanners found a point of safety on a wide plateau that overlooked a deep canyon…

Velocity dropped and Vagabond felt the pull of Callisto’s gravity. The ship swiveled on its tail and a signal triggered her landing jacks. Falling slowly through the night the latticework supports eventually made gentle contact with ancient gravel and frost. Radically new against the inconceivably old, Vagabond stood like a shining, streamlined tolchkovo against a landscape of ice and darkness…

…the cockpit’s science station offered the best views. Peering through the array of triangular viewports the mission’s planetologist smiled softly behind his beard. He winked and the motion activated a personal recorder. Softly, so as not to disturb the nearby engineer and co-pilot, he reported: “I’ll get to the details of what’s around here, but we’ve come down on a relatively flat plateau a good five kilometers from a catena that our updated maps are calling the Goblin Line. On the plain around us it looks like a collection of just about every variety of shape, angularity, granularity and variety of small rock you could find. The colors…”

Callisto_base
Artist’s impression of a manned base on Callisto

the ship’s chief scientist smiled and her eyes went to the viewports. In mission briefings, almost a year ago, she had sat through many a geology lecture. Callisto was a rugged place and despite its flatness the same could be said of the plateau where Vagabond had landed. Under Jupiter’s wan light she saw stretches of ice intermingled with whorls of gravel. Breaks and uplifts ran parallel with the distant edge of the canyon, as if the salvo of stone that had formed the distant gouge had also molded the surrounding surface. Nearby a rise showed a spot where the ground had collapsed and scree lay scattered in the low gravity. That could have happened eons ago or just yesterday. Elsewhere a garden of boulders lay tilted at crazy angles. The entire area seemed molded through shock and impact. The plateau was relatively level but certainly varied. Given Callisto’s tendency to offer terrain that was a chaotic jumble this place seemed like a relative haven…

—excerpts from “Callisto,” 2017

Worlds without end.

 

The Ghost

If a ghost is an entity lost in time then I might suggest that extra-solar object A/2017 U1 is most definitely a ghost of sorts. This visitor was discovered by astronomers just a handful of days ago on October 19th. Travelling at 44 km/sec the interloper from the depths of the unknown is now rapidly moving through the solar system. It will fade quickly and pass back into interstellar space in only a short length of time.

Plotting its path has been the focus of much scientific activity. Object A/2017 U1 has been confirmed as being of interstellar origin. Plotting the orbit was tricky especially as it was discovered after it made a harmless but close pass of Earth’s orbit. Its pass of the Sun caused the orbit to bend and be altered. Indeed, our Sun is giving it both a bump and a sling-shot of acceleration as it embarks for parts unknown.

object

No one is sure where this enigma originated or where it will next visit. There is even a debate as to whether it is a comet as A/2017 U1 has shown no evidence of a tail. Needless to say an array of instruments are now trained on this ghost. This timeless mystery might send a shiver down your spine. Where is this ghost from and where might it be going? What sights or events has it encountered across the cold, dark aeons?

All of this reminds me of a passage from Arthur C. Clarke’s novel Rendezvous with Rama:

“Then the orbit was calculated, and the mystery was resolved — to be replaced by a greater one. 31/439 was not travelling on a normal asteroidal path, along an ellipse which it retraced with clockwork precision every few years. It was a lonely wanderer between the stars, making its first and last visit to the solar system — for it was moving so swiftly that the gravitiational field of the Sun could never capture it. It would flash inwards past the orbits of Jupiter, Mars, Earth, Venus, and Mercury, gaining speed as it did so, until it rounded the Sun and headed out once again into the unknown.”

Rendezvous with Rama, 1973

When comets and asteroids are first discovered and confirmed, the person or organization that discovered the object can suggest a name to the governing body of the International Astronomical Union. Undoubtedly the Pan-STARRS 1 team at the University of Hawaii will be granted that honor.

I hereby suggest they designate object A/2017 U1 the best name possible: Rama.

rendezvous with rama 2

Interplanetary

Interplanetary

I initially learned of the British Interplanetary Society when I read Sir Arthur C. Clarke’s novel Prelude to Space. This was in 1977 and I was a high school student. The novel was one of a handful of science fiction books in our school’s library. They were all classics and Prelude to Space excited my imagination and yearning to become either an engineer or scientist. In this 1947 novel the first manned mission to the Moon is launched from the Australian Outback. It is an international endeavor and is led, in part by a British organization called “Interplanetary.” Only later did I realize that this was actually a nod to the British Interplanetary Society of which Sir Arthur was a former chairman.

The organization was founded on October 13th 1933 by a group of people who were interested in spaceflight. The organization, since inception, is dedicated to creating, exploring, and promoting concepts, technologies, and information about spaceflight. This applies to activity in Earth orbit, within the solar system, and beyond. Even as a fledgling organization it initiated some ground-breaking work, including a 1938 design of a lunar lander, the patent for a spaceflight navigation aid, and conferences on artificial satellites and remote sensing of the Earth’s surface. NATO and other national organizations took interest. The BIS has an international membership and highly respected reputation.

BIS Moon Lander 1930s
Moon Lander Design from the 1930s study as featured in the Journal of the British Interplanetary Society by RS Smith & HE Ross
BIS Meeting 1938
1938 meeting of the British Interplanetary Society and American Rocket Society. From l to r H.E. Ross, J.H. Edwards, H.E. Turner, R. Truax (in US navy uniform), R.A. Smith, M.K. Hanson, A.C. Clarke

Around the time I read Prelude to Space the BIS conducted studies related to interstellar flight. This included the famous design program for an interstellar probe called Daedalus. In recent times Daedalus has been revisited by the BIS and updated as the Icarus Project. More recently a study for a manned mission to the Martian north pole called Project Boreas was undertaken. The study looked at the advantages of establishing a scientific base at the planet’s north pole in terms of resource utilization and the ability of using the little settlement as a sort of beachhead to explore other parts of the planet.

bis daedalus
Design concept for unmanned interstellar probe “Daedalus”

The organization is very detailed when it undertakes such studies and applies solid engineering and scientific principles to its designs and reports. In many cases they serve as a touchstone and lay the foundation for follow-on work where such ideas become reality. Indeed, this fall has seen a symposium on new launcher systems and their potential impact on Mars exploration. And this November the BIS will offer a symposium on space elevator design and development. There seems to always be something new taking place at the British Interplanetary Society and it is certainly an organization to watch.

 

Tha-Thump!

Tha-Thump!

On an October’s day in 1947 it dropped from the belly of a converted piston-engine bomber and heralded in a new era. It is rare to write such a sentence without the “it” being some type of devilishly-crafted ordnance. In this case the item dropping out the bay of the B29 Superfortress was a tiny rocket plane designated the Bell X-1. The plane’s pilot, Captain Chuck Yeager, had nicknamed the plane the Glamorous Glennis, after his wife. It was one of many aircraft named after Mrs. Yeager. Each of those, both before and after 1947, represent something of a compact catalog of aviation history.

The Bell X-1’s development is a two-fold story: plane and engine. In many ways the interest in a rocket powered aircraft goes back decades, but the X-1’s genesis is likely somewhere around 1942. In Britain, the Ministry of Aviation, spurred on by the prevailing air war threat from Germany, began to secretly develop technologies that might allow supersonic flight. A company called Miles Aircraft began to develop a turbojet-powered engine called the M52, among other technologies.

Later, in 1945, the British and Americans signed an agreement to exchange information on supersonic research. Around this time Bell Aviation was given the go-ahead to build three XS-class (“eXperimental, Supersonic) planes. Ultimately the American planes would use a liquid fuel rocket engine created by a company in New Jersey called Reaction Motors, Inc.

Reaction Motors built and delivered a four chambered rocket engine with production designation XLR-11. The engine was one of several early progenitors of rockets that would someday take spacecraft beyond the Earth. Beginning in the 1920s there were little pockets of rocketeers working in Europe and North America. In the United States members of the American Interplanetary Society began rocketry experiments and by 1930 had founded a nascent little company that worked out of a converted bicycle shop. By the mid-1940s scrappy little Reaction Motors, Inc had years of experience in this field. The XLR-11 used a diluted form of ethyl alcohol as the fuel and liquid oxygen as the oxidizer. Nitrogen charged (pressurized) turbo-jets established enough of a pressure level in the engine’s thrust chambers to maintain a controlled yet explosive combustion.

bell x1 sota
Figure 1: The Bell X-1 was a state of the art research aircraft complete with sophisticated scientific instrumentation. Drama aside, it was a flying science platform.

Production of parts followed a parallel path with the plane and engine developed separately but then integrated at a Bell Aircraft facility in Buffalo, NY. By the shores of Lake Erie, a brightly painted bullet with wings received a state-of-the-art rocket engine with which it would challenge the fabled sound barrier. The plane was in many ways the first of its kind but is the result of decades-long progress in engineering experimentation, design, and aviation know-how.

This slideshow requires JavaScript.

More tests were completed at Muroc in the California desert northeast of Los Angeles. The first recognized supersonic flight happened on October 14, 1947. The plane reached Mach 1.06 at an altitude of 13000 meters. Yeager and his plane experienced significant vibrations throughout the fuselage as they approached the sound barrier. As the plane propelled itself through the sky the air ahead of the X-1’s nose became increasingly compressed. When the speed of sound was suddenly exceeded the flying became smooth and the air around them seemed eerily still.

There is little debate around the significance of this event and by “recognized” this meant that level, sustained supersonic flight in excess of 1100 km/h had been achieved. There had been a few claims from reliable witnesses to this effect during World War Two. It is likely that some aircraft at that time, particularly high performance fighter aircraft that went into steep dives, reached or exceeded the sound barrier. An experimental Luftwaffe plane called the DFS-346 was captured and modified by the Soviets at the end of the war. It was flown in late 1945 and is rumored to have surpassed the speed of sound while being flown by German pilot Wolfgang Ziese.

The flight of Yeager was a milestone but at the time was considered a secret. The story was eventually leaked to Aviation Week magazine and then announced in a news story in the Los Angeles Times in late December of that year. The event was recognized by the National Aeronautics Association and the Collier Trophy was awarded to Yeager at the Truman White House in 1948. Needless to say the spilled secret became a world-wide sensation.

Yeager’s flight in the Bell X-1 is remembered in biography and film, especially in 1983’s The Right Stuff. There is a memorable scene when the Glamorous Glennis breaks the sound barrier and two concussive thumps rattle the onlookers far below on the desert floor. It seems as if the little plane and pilot have been lost. But then somebody spots the X-1 in the sky. It is no mirage and after its engines run out of fuel Yeager glides the plane to a safe landing.

Years later, when space shuttles returned to Muroc after long flights in orbit, they would drop below the sound barrier to that same double sonic boomTha-thump, thump. It always seemed like those amazing spacecraft were tipping their hats to a storied and near-mythic history.

October Bridge

October Bridge

A walk on the Erie Canal Trail last night revealed a new aspect to some of the wildlife that has managed to adapt to our urban environment. Year round there are plenty of waterfowl, songbirds, chipmunks, squirrels, groundhogs, raccoons, and the occasional fox to be seen. These critters frequent the strip of woodland that runs next to the canal’s steep embankment. Walking along the trail last night I noticed two players converge that I hadn’t appreciated before: insects and fish.

Heading east toward a rising Harvest Moon, I caught wispy blurs of motion against the diffuse but growing light ahead. Tiny night flyers had gathered in roiling, spherical swarms. The evening was cool with a taste of growing autumnal chill. Summer was definitely over…at least for today…and these latecomers had found their way into the shadowed cleft that ran beneath the nearby highway. To these frail creatures the bright glow of the tall prismatic lamps that clustered above the interstate must have seemed like the shout of some ancient god.  If not that then I wondered what drew them here. Perhaps the heat from the paved trail or something that is only relevant to their quicksilver lives?

Walking along, soft traceries brushed my nose, brow, and ears. Tiny ethereal beings skimmed the air just above my skin, gently colliding and then spinning back into the air behind me. I walked slower to give them some warning of my approach. Trees and brush grew up around me and shadows clashed. From the murky water of the canal I heard the occasional soft splash. Glancing down the rocky embankment I saw curvilinear patterns form on the surface of the water. There were many spirals forming with a languid, liquid grace. In the shallows I saw the occasional torpedo-shape of a ghost fish. Where the little night-swarmers had been careless the dark swimmers took advantage. There was a feast going on in the moonlight!

I continued onward and the fish seemed to follow me eastward. Were there many in the canal or did some combination of my headlamp, the moon, and the insects draw them along like a living tide? The path was bordered now by young, slim maples and the wide trunk of an oak. Amid parchment-dry leaves greenish husks lay in witness to a walnut tree’s scattershot attempt at immortality. A shadow loomed in a wide, geometrically straight line where a bridge cut across the dark sky.

I paused and looked up at the bridge’s archway of perfected, modern truss-work. Red and green lamps glowed like old-fashioned lanterns to show any boaters the navigational right-of-way. The bridge was new and it had only opened near summer’s end. Its form stood large and was a tribute to the months of work that had gone into its design, planning, and construction.

The old bridge that was replaced had been narrow and weathered. Cars and trucks would cross in a cacophony of jarring bumps and lurches as busy wheels encountered potholes or the scars of hasty repair work. Those sounds are just memory now. The traffic above crossed the new roadway with a barely discernible hiss. That relative quiet seemed like a shout of triumph. Canal and bridge stood together like an intersection in time, old and new but both full of utility.

I walked up the pathway to the avenue, leaving history and entering the modern. The sidewalk stretched wide and I continued homeward. Crossing the new bridge I heard the distant slap of water. Below, tiny clusters of iridescent wings glowed within the street lights. All just a passing signature of a night that might never come again.