20 December 2006

Winter Solstice

Winter officially arrives Thursday December 21st at 4:22 pm. This is the quiet conclusion of six months of change as the Earth moves from the first point of Summer (Summer Solstice) and travels approximately 300 million miles around the Sun to the first point of Winter (Winter Solstice). On Thursday, the exact time from sunset to sunrise in San Francisco is 14 hours and 27 minutes - the longest night of the year. In the southern hemisphere of the Earth this is reversed and Thursday marks the longest day and the start of Summer. There is a lovely symmetry in the ebb and flow of the seasons. The Winter Solstice is a very important day in the ever-flowing cycles of the Sun and Earth because although the Solstice signals the completion of our move into darkness, there is hope for the future because the solstice indicates that the days are now going to be getting longer.

The skies have been changing and the cloud cover as well. If you love to look at the sky and see the stars, moon and planets, then you have been unhappy with the number of cloudy nights in December - that is, until this last week when the clear skies afforded a dazzling view of the winter sky. If the coming days allow, there will be fantastic sunset views of the Moon and Venus as they emerge from the glare of the Sun and dominate the western sky. The Moon, of course, moves quickly through its phases and as it does so, it appears higher and higher in the sky at the moment of sunset. By watching the sky from the same place on consecutive nights you can detect the motion and see the changing phase of the Moon. On the other hand, Venus is rising out of the glare of the Sun and will, over the next six months, brighten and move higher in the sky.