Cumberland-Times Sky Columns
December 2005

December 4 - Yule, Ancient and Past
December 11 - Our Allegany Leaves
December 18 - Winter Seasons Compared
December 25 - What Did the Magi See?

December 4 - Yule, Ancient and Past

The word Yule comes from the Norse jul, which is from the Scandinavian greeting, god jul for 'Merry Christmas'. The term Yule is associated with the Yule log, a large log placed on the fire so as to burn for 12 nights. As Christmas falls about the same time as the shortest day of the year and lowest sun (December 22nd this year), it was a time to gather about the fire. The 12 nights connected with the 12 months of the year. Also 12 lunar months are only 354 days long, so roughly 12 more days need to be added to make a complete year.

The end of the year festivities can be traced back to ancient Mesopotamia, the cradle of the first civilization and now the turbulent country of Iraq. Rather than a time of celebration, Yule was a time of crisis. For each year, the chief god Marduk's struggle with the forces of chaos was reenacted. The Mesopotamians had three duties: 1. Purify themselves of evil brought on by their sins. 2. Renew the strength that had drained away through the year. 3. Find a scrapegoat to be punished or killed for their offenses. In this 12 day festival, the King was stripped of his insignia. He then had to swear that he had nothing against god's (Marduk) will. There followed a reenactment of the origin of the world in which Marduk just barely triumphed over chaos. There was a 'mock king', a criminal who donned royal garb during the festival. At the end, he would be stripped of his garments and killed in place of the real king. I find this tradition ironic as Iraq is once again a land of chaos in which some leaders of the interim government have been slain by the insurgents.

Two thousand years ago, the Romans celebrated Saturnalia, named after the god Saturn, the first ruler of the gods, overthrown by his son Jupiter. Saturnalia began in mid December and lasted 12 days. The Romans celebrated these days, eating big meals and gave each other good will gifts called Strenae. The halls of the Roman houses were decked with boughs of laurels and green trees, with candles nearby to ward off the spirits of darkness. December 25th, abouit the middle of Saturnalia was a special day to the Persian god, Mithras, the spirit of the invincible sun. For on this day, the sun, having reached its lowest height, would slowly begin to increase its light. The early Christians might have selected December 25th to honor the birth of the Savior, to displace the pagan celebrations of both the Romans and the Persians.

December 11 - Our Allegany Leaves

One of the biggest projects my neighbors undertake every fall is removing the fallen leaves from their yards. Most rake and bag, but a few have machines that suck the leaves into bags. I have often wondered how many fallen leaves are there? I could of course, steal a big bag of leaves and carefully count the leaves inside. But then for every bag of leaves put out in trash, there are many more leaves in the woods that never get picked up. Finding how many fallen leaves in Allegany County requires an approach that scientists call back of envelope estimating. This approach can give you an estimates for such quantities as the number of grains of sand on Maryland's Eastern Shore or the number of worms in your backyard! The drawback of this method is that you may be off by a factor of 10, either under or over in your estimate.

We will start with the area of Allegany County, which is 425 square miles, equivalent to a square 20.6 miles on a side. The fraction of Allegany County that is wooded is about 80% ; the remaining 20% are our roads, house lots, farms, stores, shopping malls, schools, bodies of waters such as ponds, rivers, creeks, etc. This gives us 340 square miles of forests.

How many trees are there in this area? As you can see from the roads or Interstate, the density of trees varies. Let's suppose an average tree is separated by 20 feet from the next average tree. Then each tree would occupy an area of 400 square feet. Can this area give us an estimate of the number of trees in our county?

We have to convert square miles into square feet. One mile = 5280 feet. Then each square mile would have 5280 x 5280 square feet or 27.9 million square feet.
Then the number of average trees per square mile would be about 70,000 average trees. But we have 340 square miles of woods in our county. Multiplying the above number of trees per square mile by 340, we get 23.7 million trees in our County. With a county population of 75,000, there are over 300 trees per person.

How many leaves fall off an average tree? (We will ignore trees like fir that don't shed.) Let's take 10,000 leaves will be the yield of an average tree. (I asked a forester for this estimate.) Then the total number of leaves in our county would be 23.7 million x 10,000 or 237 billion leaves! (A billion is a thousand x a thousand x a thousand; a 1 followed by 9 zeroes.) So the number of Allegany County leaves could be as low as 23.7 billion or as high as 2.37 trillion. The first number is 237 billion divided by 10 while the second number is 237 billion multiplied by 10.

How much would these leaves weigh? Let's suppose that an average fallen leaf has a mass of 0.5 grams (1 gram = weight of a big paper clip). Since there are 454 grams in a pound, our leaf harvest has a weight of about 260 million pounds! If we have 75,000 people in Allegany County and the average weight per person is 150 pounds, then our total people weight would be about 11.3 million pounds. Thus all county leaves are about 23 times heavier than the people. Allowing for error, there may be could be as little as 2.3 times to 230 times our body weight in leaves.

December 18 - Winter Seasons Compared

Early this Wednesday afternoon (December 21st), winter officially begins. Winter starts when the sun's direct rays (shines overhead) reach farthest South on the Tropic of Capricorn (latitude 23.5 South). This event will take place in the Pacific Ocean over a thousand miles to the west of Chile's Atacama Desert. This winter season will last until March 20th, nearly 89 days in length. Spring 2006 lasts nearly 92 days while Summer 2006 lasts nearly 94 days. The reason why winters are shorter than the spring and summer is that in early January, the Earth is closest to the sun. The Earth then moves faster along its path, speeding up winter (1/4 of the Earth's orbit). In early July, we are farthest from the sun, moving more slowly and adding to the length of summer.

While winter has the same length for all northern hemisphere areas, there is a great variation in the sun's height and length of daylight. At the start of winter, our area (latitude 40 degrees North) has about 9 hours and 20 minutes of sunlight, two hours of twilight and about 12 hours and 40 minutes of darkness. At the North Pole, the sun set in late September and will not reappear till mid March. At latitude 60 degrees North (southern tip of Greenland, Seward, Alaska, Helsinki, Finland), the sun doesn't rise till 9 a.m. local time and sets before 3 p.m. local time, only visible for 6 hours. Since the sun's path to the horizon is at a low angle, there are about 2 hours of twilight (before sunrise and after sunset). At latitude 20 degrees North (Mexico City, Guantanamo Bay, Mecca, Bombay, Hanoi, Hawaii) the sun rises 6:30 a.m. local time and sets 5:26 p.m. local time. There daylight lasts nearly 11 hours with 45 minutes of twilight prior to sunrise and the same amount after sunset. At the equator, there are no seasons as the sunlight each day lasts about 12 hours for the entire year. Twilight at the equator lasts only a half hour as the sun rises vertically and sets vertically. At the equator, there is actually more warming by sunlight in March and September when the sun's path is higher than in June or December.

Since the seasons are reversed in the Southern Hemisphere, their summer starts this Wednesday. The sun down under then has its highest sky path and shines longest for the year. Just as winter is our shortest season, for the Australians, South Africans and Argentinians, summer is their shortest season.

As we approach the start of spring (March 20), daylight over most of the world approaches 12 hours with the sun rising nearly due East and setting nearly due West. At the North Pole the sun appears after being gone for nearly 6 months. It takes about 24 hours for the sun to completely clear the horizon. First we see its top edge, then its middle and finally its bottom edge. All through this period, the sun slowly moves around the horizon from left to right. At the South Pole, the sun begins a slow disappearance over about 24 hours; first its top edge slides below the horizon, then the middle and finally the top of the sun. The sun's horizon motion at the South Pole is from right to left.

December 25 - What Did the Magi See?

One of the most interesting topics on the interface between science and the Bible is the Star of Bethlehem. Can science possibly tell us something about the Star? In any serious discussion of this heavenly sign, one must assume that the Star was real, not a fleeting vision seen only by the Wisemen. This allows us to consider Matthew's account of the Star in terms of what natural phenomena could explain some of its aspects. First, the Star was seen in the East (where Wisemen resided), prompting them to make a long journey to Judea. Second, on the way to Bethlehem (a mere 6 miles from Jerusalem), the Star again appeared, and guided the Wisemen to the house where Jesus lay.

There is a 2001 book, "The Star of Bethlehem" by Author Patrick Moore, who has written dozens of popular and well researched books on Astronomy. (Published 2001 by Canopus Publishing, ISBN 09537868 2 X) Moore mentions that the Star was also mentioned by Ignatius, a 2nd century Bishop of Antioch in his letter to the Ephesians. The Star is also mentioned in the Protoevangelium of James, one of the infancy Gospels left out of the New Testament. Moore also suggests that the Magi (or Wisemen) were likely priests of Zoroaster, who believed that there would come a King who would resurrect the dead and bring an era of peace.

Moore points out that our present year number (2005) is likely incorrect. Our AD (year of the Lord) dates were based on the calculation of Dionysius Exiguus, a Sycthian monk who lived in sixth century AD Rome. By ignoring the absence of the year zero and the four years that Augustus (successor of Julius Caesar) ruled as Octavian, our year number is probably off by at least 5 years. (That would make this year 2010 and not 2005!) So Jesus was likely born around 5 BC. The historian Flavius Josephus states that King Herod died in 4 BC, soon after an eclipse of the moon.

Were there any unusual sights in the sky about this time? Moore mentions the triple conjunction (three fold coming together) of Jupiter and Saturn in 7 BC. Jupiter outshines the brightest night star while Saturn's brightness depends on whether the rings are tilted or edgewise. A less likely set of conjunctions were the close pairing of Venus and Jupiter, one in 3 BC and the second in 2 BC.
Chinese records mention a comet or 'broom' star seen in March and April in the morning sky of 5 BC. Moore mentions an exploding star (Supernova) and very brilliant meteors. Moore finally concludes that no natural object can explain the gospel account of the Star from Matthew.

Another recent book is "Astronomical Enigmas" by Mark Kidger. (Published 2005 by Johns Hopkins University Press, ISBN 0-8018-8026-2) Chapter 3 is "What Was the Christmas Star?" Kidger makes the point that Luke offers more detail about Christ's birth than Matthew but without mention of the Star or the Magi. Kidger also mentions that in Numbers the soothsayer Balaam mentions that "a star will come out of Jacob and a scepter shall rise out of Israel". Kidger also mentions that there was a census called by the Emperor Augustus in 8 BC. Quirinius served as the emperor's legate in Syria in 6 and 5 BC. (He actually took the post of governor in 6 AD, ten years after Herod's death.)

Kidger notes that the first known record of Christmas on December 25th was 336 AD. Luke's description of the shepherds in the fields, attending their sheep is not characteristic of winter. It is much more likely that Christ was born in the spring, when shepherds watch their crops all through the night, when lambs are likely to be born.

Kidger concludes that the Star might have been a combination of sky phenomena, first the 3 fold conjunction of Jupiter and Saturn in 7 BC, followed by a new star or Nova in 5 BC (which Moore characterizes as a comet).