With the onset of November and the turning back of our clocks, our world settles into shortened days and lengthy nights. Indeed, our nights from this time until late January always seem to be especially dark – darker than any other time of year.
The absence of snow on the ground amplifies this darkness. One of the most overlooked benefits of snow cover is its reflective quality, which lessens the dark of night, a quality I appreciate more with each passing year as my eyes age and lose their night vision.
There is one benefit to this often-oppressive darkness, however: the night sky is never as vibrant, and as I stand out on my deck at night, smoking my occasional cigarette, I have been reflecting on the wonders of our skies.
Whether or not people recognize the term “solstice,” almost everyone seems to know that December 21 (or 22nd in some years) marks the beginning of winter. They also know that the day marking the beginning of winter is the shortest day of the year, with less than 10 hours of daylight at our latitude.
The astronomic event we call a solstice is actually the point at which our sun is at its maximum angular distance below the equator – 23.5 degrees. At this point, our sun is directly overhead what we call the Tropic of Capricorn at noon. Conversely, on June 21 or 22, our sun is at its maximum angular distance above the equator (also 23.5 degrees) and is directly overhead the Tropic of Cancer at noon. This event marks the beginning of summer and is the longest day of the year.
The summer solstice is a long way off, however, and it is winter and the darkness that occupy our lives. Throughout recorded history, this time of year has been filled with mystery. Indeed, virtually every religion has attached special significance to this time of year, often with celebrations honoring the promise of new light in a period of profound darkness.
The celebration of Christmas, for example, is filled with the imagery of light. From the decoration of our trees and homes with white or colored lights, to the stars we place at the top of our tree; from the story of the star rising in the east to guide the three wise men to Bethlehem, to the birth of Christ, “the light of the world.”
The celebration of Hanukkah (also known as the Feast of Dedication or the Feast of Light) also involves light in a more direct though no less mysterious way. Hanukkah celebrates the victory of the Maccabees over Antiochus Epiphanes in 165 B.C. In particular, Hanukkah celebrates the miracle that allowed a lamp to burn for eight days when there was only oil enough for one day.
A more recent celebration is Kwanzaa, a seven-day secular celebration of African heritage by African-Americans. Each day of Kwanzaa is dedicated to a particular principle focused on family and culture and is marked with the lighting of a candle on a seven-branched candelabrum.
There are other celebrations at this time of year in other parts of the world and many of these incorporate lights amid darkness, as well. And all have mysteries, which they honor and cherish.
And then there are the wonders and mysteries of space exploration. Out there, in the dark night sky are the Voyager spacecrafts and, in particular, the Pioneer 10 spacecraft. Launched on March 2, 1972, Pioneer 10 has been quietly exploring space for almost 40 years. Its original mission was to explore Jupiter, a mission it successfully accomplished. And then, scientists on Earth did something quite extraordinary: they used Jupiter’s gravity to “slingshot” Pioneer 10 out toward the farthest reaches of our solar system.
In 1983, Pioneer 10 left our solar system, and it continues to travel outward. In October of 2009, the tiny explorer was estimated to be 100 astronomical units from Earth. To give you an idea of just how far this is, an astronomical unit is the distance of the Earth from our Sun, or 92,955,087.3 miles. As if all these numbers aren’t staggering enough, Pioneer 10 continues to travel away from Earth at a speed of 28,000 miles an hour, or, 672,000 miles per day.
Scientists can no longer communicate with Pioneer. The last signal received from the spacecraft was on January 7, 2003 and an attempt to contact the Pioneer on February 3 of that same year failed. In effect, Pioneer 10 has outdistanced our current technology. And still it travels outward – so far distant that our sun is no larger than any star we see in the night sky. A small nuclear heater provides the craft with power – power that should last for hundreds of years.
So amid all the mysteries this time of year engenders, consider Pioneer 10 this year as it celebrates its 40th anniversary all alone. A small, man-made explorer, out somewhere in the greatest mystery of all: the universe. Since we can no longer communicate with this craft, it has now, effectively, assumed a life of its own, an emissary of Earth left on its own to explore a darkness virtually unimaginable to the human mind.