Winter Milky Way

StarDate: February 15, 2012

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The lights of our galactic home, the Milky Way, arch high overhead on February evenings. As the sky gets dark, the Milky Way stretches from southeast to northwest, through the point directly overhead. It’s quite faint, though, so you need dark skies to see it — city lights will wash it from view.

The glowing band that we see as the Milky Way is actually the disk of the Milky Way galaxy seen from the inside. When we view it in winter, we’re looking away from the galaxy’s crowded center and toward its less-populated suburbs. As a result, the winter Milky Way is a good bit fainter than the summer Milky Way; more about that tomorrow.

The galaxy’s disk spans about a hundred thousand light-years, but it’s only a few thousand light-years thick. As a result, the Milky Way isn’t very wide as it stretches across the sky.

Even so, that narrow band is showing us the glow of countless stars. They’re all so faint and far away that we can’t see them as individual stars. If you look into the Milky Way with binoculars, though, you’ll see hundreds of separate pinpoints of light. And with a telescope, the numbers climb into the thousands or even millions.

To follow the path of the Milky Way, look southeast in early evening for Sirius, the brightest star in the night sky. The Milky Way stretches from that region of the sky to Taurus, the bull, high overhead, to W-shaped Cassiopeia in the northwest — a sky-spanning vista of our galactic home.

 

Script by Damond Benningfield, Copyright 2011

 

For more skywatching tips, astronomy news, and much more, read StarDate magazine.

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