METEORS IN THE NEWS
Meteors have certainly been in the news in recent weeks. If you have missed these stories, here is a recap.
The Peruvian Meteorite, September 16
Late Saturday night, September 16th, an orange fireball streaked across the Andean sky and crashed into a muddy field near Carancas, a sparsely populated highland wilderness about 6 miles from Lake Titicaca on the Peruvian border with Bolivia. The water-filled elliptical crater was 42 feet wide and 15 feet deep, but there was no immediate sign of wreckage or meteorite fragments. Over the next few days roughly 150 to 200 visitors to the crater reported smelling a foul stench and exhibited symptoms of dizziness, nausea and dermal injuries.
By September 21, verification of the impact was found in the South American seismic records. The impact registered a magnitude-1.5 tremor, a force as great as an explosion of 4.9 tons of dynamite. Also, and iron-rich magnetic fragment measuring 3 inches in length was recovered from the site.
By September 24, Peru's Mining, Metallurgy, and Geology Institute confirmed that the impact site coincided with a natural underground deposit of arsenic, and that visitors to the crater had inhaled arsenic fumes which, in addition to the excitement of the of the event for the local residents, would certainly have contributed to the symptoms of headache and nausea. As another item of interest, one local astronomer noted that this was the first confirmed Peruvian meteorite fall since June of this year, when another meteorite fell in the Arequipa province.
Finland Superbolide, September 28
Late Friday night, September 28th, a fireball streaked over Finland. Nicknamed the "super-meteor," the object was reported to be a superbolide, a fireball more than 100 times brighter than a full moon, and the brightest seen over Finland in more than 30 years. The meteoroid entered the atmosphere over Northern Ostrobothnia, passed over much of northern and eastern Finland and then exploded in mid-air. No fragments had been recovered as of this writing. Local astronomers think the meteoroid had a mass of approximately 200 kilograms and that the meteor was not part of any known annual meteoroid stream.
Minnesota/Iowa Fireball, October 3
On Wednesday, October 3rd just after 2pm, residents in Minnesota, Iowa and western Wisconsin reported seeing an orange and yellow fireball flash through a clear blue sky traveling from the northeast to the southwest. Some also reported hearing loud booms.
Early reports connected the fall with a wooden pallet found on a Minnesota interstate about that time, but law enforcement officials later assured the public that the pallet most likely fell from a truck on the roadway.
Because of how bright the object appeared to be in the middle of the day, local astronomers speculated that it was at least the size of a pea.
Is this a Meteor Increase?
I am certain there are many who see these news stories and wonder whether the rate of meteor falls is increasing. To the wondering, let me assure you that this is not the case. Because of the Earth’s proportion of water surface area to land surface area, and because much of Earth’s land masses have populations concentrated in specific areas, most of the fireballs and meteorite impacts go unnoticed by the general population.
These meteors, fireballs and superbolides are actually Near-Earth objects that, well, got very near the earth. Near-Earth Objects, or NEOs, are comets and asteroids that have been nudged by the gravitational attraction of nearby planets into orbits that allow them to enter the Earth's neighborhood. The comets originally formed in the cold outer planetary system and are composed mostly of water ice with embedded dust particles. The asteroids formed in the warmer inner solar system between the orbits of Mars and Jupiter, and they are composed mostly of rock and metal.
Because they are the primitive, leftover building blocks of the solar system formation process, comets and asteroids offer clues to the chemical mixture from which the planets formed some 4.6 billion years ago. If we wish to know the composition of the primordial mixture from which the planets formed, then we must determine the chemical constituents of the leftover debris from this formation process - the comets and asteroids.
On a daily basis, about one hundred tons of interplanetary material drifts down to the Earth's surface. Most of the smallest particles are the tiny dust grains released by comets as their ices vaporize in the solar neighborhood. The vast majority of the larger material originates as the collision fragments of asteroids that ran into one another many, many years ago.
About once every 100 years, rocky or iron asteroids larger than about 50 meters are expected to reach the Earth's surface and cause local disasters or produce the tidal waves that can inundate low lying coastal areas. On an average of every few hundred thousand years or so, asteroids larger than a kilometer could cause global disasters. In this case, the impact debris would spread throughout the Earth's atmosphere so that plant life would suffer from acid rain, partial blocking of sunlight and from the firestorms resulting from heated impact debris raining back down upon the Earth's surface.
Since their orbital paths often cross that of the Earth, collisions with near-Earth objects (NEOs) have occurred in the past and we should remain alert to the possibility of future close Earth approaches. It seems prudent to mount efforts to discover and study these objects, to characterize their sizes, compositions and structures and to keep an eye upon their future trajectories.
No one should be overly concerned about an Earth impact of an asteroid or comet. The threat to any one person from auto accidents, disease, other natural disasters and a variety of other problems is much higher than the threat from NEOs. Over long periods of time, however, the chances of the Earth being impacted are not negligible so that some form of NEO insurance is warranted. At the moment, our best insurance rests with the NEO scientists and their efforts to first find these objects and then track their motions into the future. We need to first find them, and then keep an eye on them.
As of October 2, 2007, 4853 Near-Earth objects (NEOs) have been discovered. 724 of these NEOs are asteroids with a diameter of approximately 1 kilometer or larger. Of this group, 874 have been classified as potentially hazardous asteroids, or asteroids that have a chance in some distant orbit to come very close to Earth.
To learn more about NEOs and about the tremendous NEO searches that are currently underway, please visit the home page of the NASA Near-Earth Object Program: http://neo.jpl.nasa.gov/
THE SKY THIS WEEK
Here are some observing highlights for the week. These events are given from the perspective of observers in the northern hemisphere. No offence to southern-hemisphere folks, it's just because where I live.
October 8, Dawn - Venus, Saturn, and Regulus shine above the crescent Moon in the east.
October 8, 2007 - Peak of the Draconid Meteor Shower. Also called the October Draconids and the Giacobinids, this shower is caused by dust from Comet Giacobini-Zinner. Meteors from the October Draconid shower may be visible from October 7 to 10. The shower peaks annually on October 8/9. The rate of the shower is variable and the peak lasts only a few hours. This shower gives a good display only when the parent comet returns to perihelion, which is every 6.5 years. The meteors will appear to originate from a point in the sky near the head of the constellation Draco, the Dragon. Meteors are best viewed from a dark-sky location. Observers in for the duration of the evening, or at least for several hours, should bring along a few things: a sleeping bag or blankets for warmth, a recliner or lawn chair, a hot beverage to help cut the chill, and binoculars to view the smoke trails of just-past meteors.
October 9, 2007 - Venus is 3 degrees south of the star Regulus
October 11, 2007, 1:01 AM - New Moon
October 12, 2007 - Mercury stationary - The body appears motionless in the sky due to the turning point between its direct and retrograde motion.
October 12, 2007 - Mercury is 1.3 degrees north of the Moon
October 13, 2007 - Moon at apogee, the point in the Moon's orbit when it is farthest from Earth.
Degree (°) - one three hundred sixtieth (1/360) of a circle
THIS WEEK IN HISTORY
October 9, 1604, Kepler's Nova First Recorded – “Kepler's Nova” was thought at the time to be a "new star," but we now understand that it was a violently exploding star, or supernova. Also called “Kepler's Star,” or “Kepler's Supernova,” it is one of the few supernovae known to have occurred within the Milky Way Galaxy. Several astronomers around Europe noticed the new star about the same time, but the first to record its appearance was Jan Brunowski, assistant to German mathematician, astronomer and astrologer Johannes Kepler (1517-1634) who was working in Prauge. Kepler did not see the new star himself until October 17. Among his other maladies, Kepler suffered from weak eyesight and crippled hands, the effects of smallpox as a child. While this limited his observational skills, it did not diminish his fascination of the heavens, which he learned at a very early age from his mother. As the Imperial Mathematician, Kepler was able to perform extensive studies of the new star with the support and protection of Holy Roman Emperor Rudolph II (1552-1612) who was also living in Prague. When it was first observed, the new star was as bright as Mars, but within a few days it grew to its greatest brightness, estimated to be magnitude -2.5, even brighter than Jupiter. Kepler studied the new star until early 1606 when it had faded until it was no longer visible to the unaided eye. Many people at the time thought the new star held important implications for several areas of interest, including astrology, astronomy, chronology and theology. In 1606, Kepler published his observations and his thoughts in is comprehensive book, "De stella nova" (the new star). Kepler's work proved that the supernova was actually in the heavens and not just a phenomenon in Earth’s atmosphere. Like the discovery of Tycho's Nova years earlier, Kepler's Nova provided evidence that the stars were not perfect and unchanging. Astronomers today more formally refer to “Kepler’s Nova” as Supernova Remnant 1604 (SNR 1604). It is located in the constellation Ophiuchus at stellar coordinates RA 17 hours 30.6 minutes, Dec -21 degrees 29 minutes; distance, less than 20,000 light-years. To date, astronomers have not found the core of the exploded star (a stellar remnant), but they can see a nebula at the position where the supernova occurred. It is especially noticeable in the X-ray portion of the spectrum.
October 9, 1992, Peekskill Meteorite - A meteorite weighing 27.3 pounds slammed a hole through the trunk portion of a red 1980 Chevy Malibu then owned by Michelle Knapp in Peekskill, New York. The hole just missed the car's fuel tank. Prior to the impact, thousands of people in neighboring states heard the sonic booms and watched the greenish fireball for over 40 seconds it traveled north-northeast for about 700 to 800 kilometers (435 to 497 miles). It was later determined from the fireball path that the object had been orbiting the sun prior to the impact. Following the event, the car was purchased by a rock collector and became an attraction at national rock and meteorite conventions. (URL: http://www.nyrockman.com/peekskill.htm)
STARS AND BARLEYCORNS
With all of this talk about falling stars and new stars, I couldn't help thinking about a folksong with a tune that has an uncertain national heritage (possibly English or Scottish), but that has been adopted into the English, Scottish and Irish repertoire of folksongs.
"The Star of the County Down" is a composition of the early 20th century. The lyric was written by Cathal McGarvey. He originally set the words to the tune "Gilderoy," which appeared with other songs as early as 1707. However, the tune best known today with "County Down" is another that apparently is even older (first time in print around 1635). This tune has been used for numerous songs, including "Divers and Lazarus" (Dives and Lazarus), "The Murder of Maria Martin," and "Claudy Banks." In 1906, composer Ralph Vaughan Williams arranged a hymn tune based on this melody that is sometimes called "Kingsford." The tune has been used for several English and American Hymns and Carols, including the hymn entitled, "O Sing a Song of Bethlehem." When sung with "County Down," the second half of the tune (the "B" part, as musicians would say) for the chorus.
The Star of the County Down
Near Banbridge town, in the County Down
One morning in July
Down a boreen green came a sweet colleen
And she smiled as she passed me by.
She looked so sweet from her two white feet
To the sheen of her nut-brown hair
Such a coaxing elf, I'd to shake myself
To make sure I was standing there.
From Bantry Bay up to Derry Quay
And from Galway to Dublin town
No maid I've seen like the sweet colleen
That I met in the County Down.
As she onward sped I shook my head
And I gazed with a feeling rare
And I said, says I, to a passerby
"who's the maid with the nut-brown hair?"
He smiled at me, and with pride says he,
"That's the gem of Ireland's crown.
She's young Rosie McCann from the banks of the Bann
She's the star of the County Down."
I've travelled a bit, but never was hit
Since my roving career began
But fair and square I surrendered there
To the charms of young Rose McCann.
I'd a heart to let and no tenant yet
Did I meet with in shawl or gown
But in she went and I asked no rent
From the star of the County Down.
At the crossroads fair I'll be surely there
And I'll dress in my Sunday clothes
And I'll try sheep's eyes, and deludhering lies
On the heart of the nut-brown rose.
No pipe I'll smoke, no horse I'll yoke
Though with rust my plow turns brown
Till a smiling bride by my own fireside
Sits the star of the County Down.
To review the history, the text, or to listen to the melody, check out
this page from the Irish Folk Music section of "Contemplations from the Marianas Trench - Music and Deep Thoughts" -
To see a GIF image file of the score of the song, or to download an
ABC file of the score, visit this page of "The Session" -
To see and hear more on the hymn, "O Sing a Song of Bethlehem," visit this page of "The Cyber Hymnal" -
Still with me? Good! Do remember me mentioning something about barleycorns? Well, here is the tie-in for that. When the tune was published around 1635 it was used as the melody for an even older English folksong called "John Barleycorn." One early version of the text appears in the Bannatyne Manuscript of 1568.
In the song, the character "John Barleycorn" is a personification of barley, an important cereal crop, and the foundation for alcoholic beverages such as beer and whisky. In the song, John Barleycorn suffers attacks, death, and indignities that correspond to the various stages of barley cultivation, reaping and malting. In fact, when author Jack London published in 1913 his autobiographical novel on his struggles with alcoholism, London entitled the book, John Barleycorn.
Some interpret the song as representing a pagan rite. Others suggest that an early form of the song may have been used by the early church in Saxon England to ease the conversion of pagans to Christianity, reasoning that John Barleycorn represented the pagan ideology of nature cycles, spirits, the harvest, and perhaps also human sacrifice, but that the song was Christianized in order to show John Barleycorn as a Christ-like figure. A popular hymn, "We Plough the Fields and Scatter", is often sung at Harvest Festival to the same tune. Below is a version of the song that was collected by poet Robert Burns and first published in 1782.
There was three kings into the east,
Three kings both great and high,
And they hae sworn a solemn oath
John Barleycorn should die.
They took a plough and plough'd him down,
Put clods upon his head,
And they hae sworn a solemn oath
John Barleycorn was dead.
But the cheerful Spring came kindly on'
And show'rs began to fall;
John Barleycorn got up again,
And sore surpris'd them all.
The sultry suns of Summer came,
And he grew thick and strong:
His head weel arm'd wi pointed spears,
That no one should him wrong.
The sober Autumn enter'd mild,
When he grew wan and pale;
His bendin joints and drooping head
Show'd he began to fail.
His colour sicken'd more and more,
He faded into age;
And then his enemies began
To show their deadly rage.
They've taen a weapon, long and sharp,
And cut him by the knee;
They ty'd him fast upon a cart,
Like a rogue for forgerie.
They laid him down upon his back,
And cudgell'd him full sore.
They hung him up before the storm,
And turn'd him o'er and o'er.
They filled up a darksome pit
With water to the brim,
They heav'd in John Barleycorn –
There, let him sink or swim!
They laid him upon the floor,
To work him farther woe;
And still, as signs of life appear'd,
They toss'd him to and fro.
They wasted o'er a scorching flame
The marrow of his bones;
But a miller us'd him worst of all,
For he crush'd him between two atones.
And they hae taen his very hero blood
And drank it round and round;
And still the more and more they drank,
Their joy did more abound.
John Barleycorn was a hero bold,
Of noble enterprise;
For if you do but taste his blood,
'Twill make your courage rise.
'Twill make a man forget his woe;
'Twill heighten all his joy:
'Twill make the widow's heart to sing,
Tho the tear were in her eye.
Then let us toast John Barleycorn,
Each man a glass in hand;
And may his great posterity
Ne'er fail in old Scotland!