A Tale of Two Skies
If you stand in the center of a spinning merry-go-round and look straight up, you’ll see the same patch of sky whirling around you — the same clouds, for example, just at a changing orientation. But if you look out instead of up, the view changes dramatically — you see different trees, buildings, and gleeful children, all rotating into and out of view with each turn.
That’s just what it’s like to look into the evening sky from the latitudes of the United States.
“Up” is due north — toward the North Star, Polaris. Earth’s axis aims in that direction, so as our planet turns, Polaris stays in the same spot in the sky. The stars that are close to Polaris whirl around it during the night. They also whirl around it over the course of the year, so that we see those stars in a different orientation for each season. Yet it’s always the same stars: the Little Dipper, which stretches away from Polaris; sinuous Draco, the dragon; W-shaped Cassiopeia; and the Big Dipper, among others.
If you face south, though, it’s like looking outward from the merry-go-round, so you see different star patterns at different times of the year. Right now, Scorpius and Sagittarius are in the southern sky in early evening. In a few months, though, it’ll be magnificent Orion and Canis Major, home of Sirius, the night sky’s brightest star.
So the southern sky brings us new sights for each season — all as we spin on the merry-go-round known as Planet Earth.
Script by Damond Benningfield, Copyright 2013
For more skywatching tips, astronomy news, and much more, read StarDate magazine.