Wednesday, December 01, 2004

Something's Missing from the Night Sky

Something's Missing from the Night Sky
by Dave Adalian

Something is missing from the night sky.

Looking north just after dark in December, stargazers will find the familiar Big Dipper of Ursa Major gone.

It hasn’t vanished. The well-known asterism is now at its lowest and most northerly for the year, so that it hangs partially hidden behind the horizon and the trees, buildings and mountains that obscure it. This is the season when whatever celestial liqueur it is that passes between these stellar vessels flows from the Little Dipper of Ursa Minor into its greater counterpart.

It may seem strange to think of the Dipper as anything other than itself, but these stars have almost as many names as there have been cultures of men gazing up at them.

It could be the low, late-autumn sweep--which sends the Dipper’s stars cutting into the earth--that prompts Britons to call the group of seven bright stars the Plow. Across the English Channel, the French call it the Saucepan.

Of course Greeks and Romans saw the Great Bear that gave us the name Ursa Major, but several other cultures around the ancient world did, too. Micmacs of North America see the four stars of the Dipper’s bowl as the feet of a bear that slowly circled the North Star. Iroquois imagine a group of hunters following a bear.

The Chumash of the Central Coast tell a story of seven boys who ran away from homes where they weren’t wanted and turned into geese, and Pawnee legend describes a sick man carried on a stretcher.

Many cultures have seen the Big Dipper as a wagon. Norse myth puts Thor at the reins, while Germanic legend says it belongs to his father Odin. Coming full circle, the Chinese version includes a horse-drawn wagon for the celestial emperor on the back of a bear.

While the Big Dipper is low after sunset, it rises quickly to stand on its handle by 10 o’clock. This happens earlier each night as we move into winter.

The middle five stars of the Dipper comprise an open cluster, all of them moving together through the galaxy. This cluster, at 75 light years to its nearest sun, may be the closest to Earth. Or not. Sol moves in nearly the same way, leading some astronomers to conclude we may be part of the cluster ourselves, our star forming from the same dust cloud as those of the Big Dipper.


This column appeared originally in the Visalia (Calif.) Times-Delta in December 2004.