By Martin Weil and Debbi Wilgoren
Washington Post Staff Writers
Tuesday, December 21, 2010; 9:38 AM
There are not many days like Tuesday, Dec. 21, 2010. Take it from people who know: astronomers. There was maybe one day like this Tuesday in the past 2,000 years.
The total eclipse of the moon, which delighted skywatchers in the pre-dawn hours, will be followed later in the day by the arrival of the winter solstice.
A total lunar eclipse occurs when the Earth blocks the sun's rays from the face of the moon. The moon is then fully in the shadow cast in space by the Earth.
In a clear, cold sky over Washington, the full moon slowly slipped into shadow starting just after 1:30 a.m. People gathered at the Washington Monument, along the George Washington Parkway and at other prime viewing spots - or on their decks and in their backyards - to watch as its bright white glow gave way to a coppery, luminescent orange.
Scattered across the rest of the night sky, the stars appeared brighter than usual in contrast.
The last time the solstice coincided with a total lunar eclipse on the same calendar day was long before any of our lifetimes, experts say. The year, according to Geoff Chester, public affairs officer at the U.S. Naval Observatory, was 1638. (Starhawk, a prominent Wiccan, told The Washington Post in an essay that the two events have not coincided since 1544.)
Chester said his research took him back to the first year of the common era and involved consulting with "a number of well-respected sources." His finding, essentially was this: "It's a comparatively rare event."
For scientists, Chester added, the coinciding of the two celestial events does not appear to have any cosmic significance.
But for Wiccans, astrologists and others, Starhawk wrote, the coincidence offers an opportunity to "step out of time. We are free of the past, and we can consciously create the future, for ourselves, for our communities, for the earth."
Few alive today are likely to see a recurrence. The next time the winter solstice and a total lunar eclipse will occur on the same calendar day will be Dec. 21, 2094.
The total eclipse began about 2:40 a.m. and lasted 72 minutes, until 3:52 a.m. The moon then continued moving through the Earth's shadow, emerging completely sometime after 5 a.m.
The winter solstice, which occurs later in the day, is the time when the sun reaches its lowest point in the northern sky. The Naval Observatory said this year's solstice will be at 6:38 p.m.
The day of the solstice is essentially the shortest of the year in the Northern Hemisphere. Many people consider to be the official start of the winter season.
This year, however, many people will require little convincing that winter has already begun. If temperature is any measure of wintriness, it is clear that December has been much colder than average in Washington.