Today, at 3:07 P.M. Eastern standard time, the northern hemisphere is tilted as far away from the sun as it ever gets, marking the moment called the winter solstice. And many New Jerseyans -- even those still finishing their Christmas, Hanukkah and Kwanzaa shopping -- will be taking note at some point during the weekend.
Richard Clarkson, a 53-year-old delivery-service manager, plans to be in Landing this afternoon, in the middle of a field, standing in a circle with others who belong to a Morris County group called the Center for Spiritual Enfoldment. Lillian Mulligan, who has been a member of a mission church in Camden for 23 years, will be having friends over to her home in Mullica Hill this evening. She and her husband will turn out all the lights in the house, go outside and pray for the light to return. Sister Miriam MacGillis, a Dominican nun, will be leading a private observance at Genesis Farm, the ecological learning center she directs in Blairstown. Brian Wilkes, who is Chief Standing Bear in the American Cherokee Confederacy, expects to be in a fire circle on ceremonial ground, around noon, with a dozen or so other Native Americans.
''It will be almost like a welcoming party,'' he said. ''Like we have an important visitor: the sun. So we say, 'Let's get everything together and light a fire so he knows where to come.' ''
Early man found his first deities in the rhythms of nature: times for hunting, planting and harvesting and for giving birth. These days people tend to consult the calendar. If it's the 25th day of Kislev (which begins at sundown on Dec. 23 this year), Jews are lighting the first candle of Hanukkah. On the 25th of December, Christians are thinking about the star of Bethlehem. On the 26th, African-Americans are lighting candles for the first day of Kwanzaa.
These celebrations are at least one of the reasons that the candle business is booming. The National Candle Association, a Washington-based trade group, says total retail sales of candles nationwide are growing at an annual average rate of 25 percent, and will reach about $2 billion this year. More than a third of those sales take place at this holiday season.
What is it about the waxing and waning of light that makes it such a peg for celebrations? Part of the answer may lie in its absolute predictability. Ice ages might come and go, rainy seasons might shorten or lengthen. But, at any given latitude, the seasonal change in the length of the day is a rock-steady beat, one that life itself is dancing to in increasingly understood ways.
''From the beginning of life, which goes back three billion years, there have been these seasonal changes in light,'' said Dr. Thomas Wehr, a research psychiatrist at the National Institute of Mental Health. ''It was one of those things that life had to cope with. And when you look across species, you find clocks that respond to daily and seasonal changes in light.''
Those clocks, he said, tend to have a common pendulum: the hormone melatonin. ''It appears to be very widely distributed,'' Dr. Wehr said. ''It's in mammals, reptiles, birds, insects, algae. Morning glories.'' And there are other clues, like a clock gene associated with fruit flies that has recently been identified in humans. ''What it's telling us,'' Dr. Wehr said, ''is that these mechanisms are very, very old from an evolutionary perspective.''
Studies on light's effects have been increasing since the 1980's, when seasonal affective disorder, or winter depression, was first identified. It is a condition that disproportionately affects women. Scientists are testing whether that disparity might be linked to another gender difference. In approximately one out of three women, compared with one out of eight men, a clock in the brain orders a cycle of melatonin production that matches the length of the day, regardless of exposure to artificial light or dark.
Clifford Geertz, a noted anthropologist now at the Institute for Advanced Studies in Princeton, has concluded that man's physical evolution was inextricably entwined with his social evolution. It is no surprise that the cycle of light and dark marked by our bodies is also marked by so many religions.