Happy New (Chinese) Year!

On Sunday, Feb. 14, while we were observing Valentine’s Day, a much bigger celebration got underway in the Far East.  That was the  Chinese New Year, the day when the Year of the Ox ended and the Year of the Tiger began.  And the celebration is still ongoing, as it lasts until the Lantern Festival on the 15th day of the month (this year, Feb. 28).

Lanterns
Creative Commons License photo credit: ken2754@Yokohama

Like most Americans, I learned the sky as imagined by westerners around the Mediterranean basin, with images from Babylon, ancient Egypt, ancient Greece and Rome, and star names preserved during the Middle Ages by Arabs. So I find it fascinating to think of an entirely different culture and how they imagined the night sky. The Chinese New Year celebration is a perfectly appropriate time to do this, especially since objects in the sky, in particular the moon and Jupiter, serve as the basis of the ancient Chinese calendar.

The date of Chinese New Year varies; it can occur as early as Jan. 21 or as late as Feb. 19. However, anyone familiar with the lunar cycle can easily predict the date for a given year. That’s because China’s New Year always begins with the second new moon after the winter solstice.

Our Gregorian calendar is a solar calendar, based on the apparent position of the sun (and thus, on the Earth’s orbit around the sun).  However, the apparent position of the sun compared to the stars is difficult to observe.  Much more readily observable are the phases of the moon.  Thus the Chinese, like many ancient cultures, adopted a lunar calendar, measuring months from new moon to new moon.  Unlike the Islamic or ancient Roman calendars, the Chinese calendar begins months with the dark of the moon–the day the moon is invisible, not the first slender crescent seen at dusk.

Full Moon
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It would be convenient if one year equaled an even number of phase cycles. In fact, however, the moon takes about 29.5 days to go through one phase cycle, so 12 such cycles is 354 days.  This is significantly less than the solar year of 365.25 days, so a purely lunar calendar quickly becomes disconnected from the seasons and useless as a guide for when to plant or harvest.   To keep their lunar months connected with the seasons, the Chinese added a rule: the second-to-last lunar month must contain the winter solstice.  If the old crescent moon of the eleventh lunar month is waning towards new and the winter solstice has not yet happened, that month is repeated.  Similar rules exist for the second lunar month (which must contain the spring equinox), the fifth lunar month (which must contain the summer solstice), and the eighth lunar month (which must contain the fall equinox).  Accordingly, the first new moon after the winter solstice always begins the last month in the Chinese year, and the second new moon after the solstice begins the next year.

Chinese astronomers noticed that every twelve years, Jupiter reappears next to the same stars.   (This is because Jupiter takes 11.86 years to orbit the Sun.)  There were twelve months in a typical Chinese year (although occasionally one was doubled, as explained above).  Also, the Chinese divided the day into twelve double-hours.  They used a system of twelve ‘Earthly Branches’ to designate the months of the year and the double-hours in a day.  Jupiter’s motion in the sky established a cycle of years analogous to the cycles of months and double-hours.  Thus Jupiter became the ‘Year Star’ (Suixing) and years, too, were designated with the Earthly Branches.

Lion Dance
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Later, as a mnemonic device, the Chinese began to associate the Earthly branches with animals.  (Sources disagree as to exactly when.)  Legends tell that Buddha (or the Jade Emperor) summoned all of the animals to him; each of the first twelve to appear became associated with an Earthly Branch.  The twelve animals are:

1) Rat  2) Ox  3) Tiger  4) Rabbit  5)Dragon  6)Snake  7)Horse  8)Sheep  9)Monkey  10)Rooster  11)Dog  12)Pig

The signs of the Chinese zodiac, then, unlike those of the western zodiac, are not constellations in the sky.  The most well known of the Chinese constellations are the 28 ‘lunar mansions.’  These are small groups of stars very roughly arrayed along the ecliptic, which is the apparent path of the sun, moon and planets across the sky.  As you’ll see in the links below, the Chinese used some stars, such as those in Orion, that are too far from the ecliptic for the moon to pass through them.  The 28 mansions were subdivided into four groups of seven; each group of seven represented one of four Chinese animals associated with the directions and the seasons:

1) The Blue/Green Dragon (Qing Long) of the East, associated with spring.  Note that the ancient Chinese color word qing was quite broad in meaning.  Blue and green were considered different shades of this broadly defined color.

2) The Red Bird (Zhu Que) of the South, associated with summer.   This mythical bird, with red and orange plumage, is distinct from the feng huang, also called the Chinese phoenix.

3) The White Tiger (Bai Hu) of the West, associated with autumn.

4) The Black Tortoise (literally Dark Warrior, Xuan Wu) of the North, associated with winter.  Xuan Wu was always shown as a tortoise with a snake wrapped around it, reflecting the folkloric belief that all tortoises were female and needed to copulate with snakes to reproduce.

Of the stars in tonight’s evening sky, those in Orion and Taurus form part of the White Tiger, while Gemini and the dimmer stars south and east of it belong to the Red Bird.

Along with the four large animals, Chinese astronomers defined three large constellations known as the three enclosures.  The largest of these is the ‘Purple Forbidden Enclosure‘ (Zi Wei Yuan) which includes all those stars near the North Pole of the sky which never set as seen from mid-northern latitudes.  The enclosure is ‘forbidden’ because it includes the North Star, which was the Emperor of Heaven because it always remains in one spot while other stars seem to go in circles around it, as if paying court.

The ‘Supreme Palace Enclosure‘ (Tai Wei Yuan) actually rises in the late evening in February.  Look east about 9 tonight for a set of stars in the shape of a backwards question mark.  We see this as the head of Leo, the Lion.  Rising under the backwards question mark is a right triangle of similar brightness.  For us, this is Leo’s hindquarters, but in China, it’s the northwest corner of the Supreme Palace enclosure.  The other side of this enclosure is a semi-circle of stars westerners recognize as part of Virgo, the Virgin.

The final enclosure, the ‘Heavenly Market Enclosure‘ (Tian Shi Yuan), won’t rise until very early in the morning in February, and isn’t in the evening sky until late May.  It centers on our constellations Ophiuchus and Serpens (Caput and Cauda), just north of the bright summer constellations Scorpius and Sagittarius.

So, I wish everyone a happy Year of the Tiger.  I’ll celebrate it by looking at the stars in a way I ‘m not accustomed to seeing them.

The Shadow Knows

Who knows how much longer the winter will last?

The Shadow knows.

Okay, so that’s not exactly how those old radio serials used to begin.  However, the idea of all-knowing shadows brings to mind a strange weather forecast that will take place in a few weeks.

Wuchak
Creative Commons License photo credit: Furryscaly

Early next month, a large rodent will emerge and look at the ground. If he sees his shadow, he scurries back into his winter den, and it is said that winter will continue for six more weeks. If there is no shadow, he stays out, and an early spring is in the offing. But, how does the groundhog’s shadow let us know how long the winter will be?

Understanding this forecast begins with knowing the cycle of the seasons.  The Earth orbits the sun with its axis tilted by about 23.5 degrees.  On about June 21 each year, the North Pole is tilted as much as possible towards the sun and the sun takes its highest path across our sky.  This is the summer solstice for us and the winter solstice for the Southern Hemisphere.  Six months later, the South Pole is tilted as much as possible towards the sun and the sun takes its lowest path across our sky.  Dec. 21 is our winter solstice and the summer solstice below the equator.  Halfway between these dates, on about March 20 and September 22, the sun is overhead at the equator and both poles are on the day-night terminator.  As everyone then has the same amount of daylight and nighttime, these dates are the equinoxes.  We can think of the solstices and equinoxes as ‘quarter days.’

We have come to define our seasons as beginning at the solstices and equinoxes.  Northern European pagans, however, paid equal if not more attention to dates about halfway between the solstices and equinoxes, called the ‘cross-quarter days.’  For them, seasons began at the cross-quarter days, while the solstices and equinoxes were the midpoints of the seasons.  A while ago, I blogged about the cross-quarter day between the fall equinox and the winter solstice, Samhain, and explained how its traditions influenced our Halloween celebrations.  Now, as January ends and February begins, we are approaching the halfway point between the winter solstice and the spring equinox–another cross-quarter day.

For the Celts, this was Imbolc (pronounced as if there were no ‘b’), sacred to Brigid, goddess of fine craftsmanship, healing, poetry and generally anything involving the higher faculties of mankind, as the Celts understood them.  Among the traditions associated with Imbolc was the belief that Brigid’s snake would emerge from its winter resting place and test the weather.  Germans used a hedgehog to forecast the weather.  If the animal in question scurried back into its burrow, it was a sign that much more winter was ahead.

8981 - St Petersburg - Hermitage - Gaius Julius Caesar
Creative Commons License photo credit: thisisbossi

In the time before the Celts encountered the solar calendar established by Julius Caesar, the actual date of Imbolc varied from year to year.  With the adoption of the Romans’ calendar, Imbolc came to be observed on Feb. 1 (just as observations of Samhain moved to Nov. 1 and the eve of that day).  The actual midpoint between the winter solstice and the vernal equinox is Feb. 3.

Feb. 2 is Candlemas Day, the 40th day of Christmas (with Christmas as day 1).  Christians observe this as the presentation of the baby Jesus at the temple.  As has often occurred when Christian observances nearly coincide with pagan ones, folklore from one became attached to the other.  Thus, as northern Europeans began to migrate to America, they had a weather forecast descended from Imbolc associated with Feb. 2.  Upon arriving here, they replaced the hedgehog (not native to America) with a uniquely American animal, the groundhog.

Light and Dark
Creative Commons License photo credit: ZeroOne

Let’s look more closely at the rules for the Groundhog Day forecast.  If we don’t want the groundhog to see his shadow on Feb. 2, then we must not want sunshine that day.  Good weather (bright and sunny) is a bad omen, while bad weather is a good omen.  This page quotes some sayings from Europe and America which make this explicit.  To appreciate this apparent reverse psychology, let’s consider another day on which bad weather is welcome: Christmas.

Think back to early last month, when Houston experienced a snowfall on Dec. 4 (it had never snowed that early in the winter here in Houston).  Think back even further to our Christmas Eve snowfall in 2004 (our first white Christmas ever).  Such unusual weather (for us) reminded many of favorite holiday songs such as ‘Let it Snow’ or ‘White Christmas.’  “Now this feels like Christmas,” many told themselves.  Now recall the bitter cold a few weeks ago this January.  Did anyone break into song?  Was anyone saying, “At least this feels more like January?”  Why the double standard?  Why is the type of weather we welcome at Christmas just bad weather when it happens in January?

It seems that people who made their living off the land and thus depended on regular seasonal changes constantly looked for reassurance that the natural cycles were functioning properly.  A winter that was truly wintry was therefore a good omen.  If winter happened when it should, then perhaps spring, summer, and the harvest would occur in their proper times, and everything was in balance.  If winter were warm and sunny, however, then something was wrong.  If winter was not happening in its season, then other seasons might also fail to appear.  In particular, people feared that failing to have a true winter at the proper time would require ‘remedial’ winter during springtime.

In time, the winter solstice and the cross-quarter day, Imbolc (later Christmas and Candlemas Day) came to stand in for the whole winter.  Thus, wintry weather on Christmas and on Feb. 2 is a good omen, while bright, sunny weather on these days is a bad omen.  And so, the sight of his shadow frightens the groundhog back into his burrow.

Into the sun
Creative Commons License photo credit: James Jordan

The winter of 2009-2010 has been more severe than usual, not just in Houston but across much of the Northern Hemisphere.  Thus, many can sympathize with those who are looking for any possible sign of spring.  As it turns out, there is a sign of approaching spring that becomes noticeable as February begins–the greater height of the sun.

Ever since the winter solstice, we have seen the sun take a slightly higher path across our skies each day.  However, the difference in height is difficult to notice until February.  This is because the height of the sun during the year varies like a sine wave.  There is little variation near the maximum and minimum; most of the change occurs midway between these points.  During February, March and April, the sun’s higher path is more apparent than in January. All shadows, including those of groundhogs, get noticeably shorter each week.  If you can’t measure shadows during the day, try observing the same change in the position of sunset.  From the same vantage point, notice where the sun sets once each week during February, March and April.  You’ll notice a distinct shift towards the north (towards the right as you face sunset in the west) with each observation.  Since this happens every year as winter turns to spring, you now have reliable assurance that spring is on the way.  No need to be afraid of shadows.

Great Caesar’s Ghost!

DSCF2360.JPG
Creative Commons License photo credit: glacial23

Why is this month called July? The short answer is that July is named for Julius Caesar. The longer answer involves the ancient Romans’ attempt to keep track of the year.

There are two bright lights in the sky which can help us mark the passage of a year: the Sun and the Moon. Since the year is defined by the Earth’s motion around the Sun, it is best to measure it using the Sun’s apparent changing position among the stars. However, this observation is difficult, since we do not see the Sun and the background stars at the same time. The first ancient culture to do this was ancient Egypt, where the rising of Sirius just before the Sun occurred right before the annual flood of the Nile. Egyptians marked the beginning of each new year with this event.

Sirius vanishes for several months each year when Earth’s orbital motion puts the swath of sky containing Sirius on the far side of the Sun, and therefore behind the Sun from our point of view. Eventually, Earth’s continued motion brings that swath of sky from behind the Sun, allowing Sirius to rise just before dawn. To measure years by the reappearance of Sirius, then, is to measure them by the positions of the Earth and the Sun–a solar calendar.

Lune
Creative Commons License photo credit: ComputerHotline

The Moon, by contrast, is much easier to observe each clear night. Most ancient cultures, including the ancient Romans, measured months by tracking the cycle of lunar phases from new to full and back to new. Since a lunar phase cycle takes 29.5 days on average, we might expect the month lengths to alternate between 30 and 29 days. However, the Romans considered even numbers unfortunate, so their months, beginning with March, had the following lengths:

Martius 31, Aprilis 29, Maius 31, Junius 29, Quintilis 31, Sextilis 29, September 29, October 31, November 29, December 29, Januarius 29, Februarius 28

Yes, January and February were tacked on to the end of the year at first (the Romans originally did not count days at all between December and March) and later moved to the beginning. (In 153 BC, Roman consuls began to take office as of January 1, making that the start of the civil year). February was given an even number of days (making it unfortunate) so that the year as a whole would be fortunate, with an odd number of days.

Unfortunately, there is not an even number of lunar phase cycles per solar year. A cycle of 12 lunar months is 354 days long, 11 days shorter than the cycle of seasons which is about 365.25 days long. (The Roman calendar outlined above has 355 days, because the Romans preferred odd numbers). If this is not corrected, each month occurs 11 days earlier each year, compared to the start of the seasons, and months are no longer associated with the seasons. This is exactly what happens in the Muslim calendar. To keep months roughly aligned with the seasons, an extra 13th lunar month must be added to some years, as in the Hebrew calendar. Thus, the Romans periodically added an extra month, called Intercalaris, between February and March. After all, February was originally at the end of the year.

Martes 13
But is it really? Ordinary Romans didn’t
know.
Creative Commons License photo credit: kozumel

However, it was up to the Roman priests to decide which years would have the extra month. Priests often used this power to arbitrarily shorten the terms of political opponents and lengthen the terms of their friends. Also, the extra month was considered unlucky and avoided in times of crisis, such as the Second Punic War against Carthage. By Caesar’s time the calendar had become so chaotic that regular Roman citizens, especially those far from Rome, did not know the date.

Even as he waged civil war against his rivals for power in Rome, Caesar began many popular reforms as dictator. He offered citizenship to many more Romans and enlarged the Senate to provide more representation. He canceled one fourth of all debts. And he reformed the calendar so even the average Roman could know the date.

While in Egypt, he consulted the Greek astronomer Sosigenes, who told him of the Egyptian solar year of 365 days. Caesar thus decided to add ten days to the 355 day Roman calendar. First, in 46 BC, he realigned the months with their traditional seasons by using Intercalaris and by adding two more months between November and December. 46 BC thus became a 445-day year, the ‘last year of confusion.’ Beginning in 45 BC, the new 365 day Julian Calendar was to come into effect. Caesar added 2 days each to January, ‘Sextilis’, and December, and one day each to April, June, September, and November. The original long months (March, May, Quintilis, and October) remained 31 days long. February, the ‘unlucky’ month devoted to religious rituals, also remained unchanged.

The extra month Intercalaris was dropped forever, replaced by an extra leap day every four years. As Romans had added the extra month in late February, Ceasar placed leap day there as well. The year took its modern shape starting in 45 BC:

January 31, February 28 (29), March 31, April 30, May 31, June 30, Quintilis 31, Sextilis 31, September 30, October 31, November 30, December 31

Julius Caesar
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get directly down

On the Ides of March (March 15), 44 BC, Julius Caesar was assassinated. The Roman Senate felt that a fitting tribute, given Caesar’s work with the calendar, would be to name a month of the year after him. Caesar had been born on the 4th day to the Ides of Quintilis (Quintilis 12th). When that month came around in 44 BC, the Senate proclaimed that from that year on, Quintilis shall be known as Julius (or July in English).

Romans at first counted inclusively, i.e. 1, 2, 3, 4/1, 2, 3, 4/1, 2, 3…. This led them to use leap years too often. The first Roman emperor, Caesar Augustus, noticed this and suppressed all leap years between 9 BC and AD 8. In recognition of this, the Senate offered Augustus a month, and he chose Sextilis, the month when his greatest victories had occurred. Thus Sextilis became August.

As it turns out, the year is not exactly 365.25 days long; its closer to 365.2422 days. The Julian year is thus 11.8 minutes too long on average. There is some evidence that Caesar, Sosigenes et al. knew of the error but considered it insignificant. However, those 11.8 minutes add up to 1 day about every 130 years. In 1582, Pope Gregory XIII noticed that the year had gotten off by 10 days since AD 325, when the Nicene council set the rule for calculating the date of Easter. The Pope decreed that October 15 would follow October 4, 1582, and that century years are leap years only if they are divisible by 400 (thus 2000 was a leap year, but 2100, 2200, and 2300 will not be). Our current calendar, then, is the Gregorian calendar, not the Julian.

But consider this: Pope Gregory did not change the length of the year, nor the lengths of the months, nor the fact the the leap day is in February. All of these decisions by Julius Caesar remain in effect. Caesar, then, still deserves his place of honor in the year.

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