Summer Milky Way

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One of the great joys of a dark summer sky is the Milky Way -- a delicate band of light that looks like a glowing cloud. Its filaments of stars and voids are truly awe-inspiring -- but you have to get far away from city lights to see them.

As darkness falls, the Milky Way arcs high across the eastern sky, running north to south. The W-shaped constellation Cassiopeia is near its northern end, the bright stars of the Summer Triangle mark its middle, and teapot-shaped Sagittarius anchors the southern end.

That band of light outlines the disk of the Milky Way galaxy. We're inside the disk, so the stars of the Milky Way surround us. But there are more stars when we look in the plane of the disk than when we look above or below it. It's like seeing the trees in a forest when you look to the sides, but open sky when you look up.

The galaxy spans a hundred thousand light-years, and it contains several hundred billion stars. The closest and brightest stars show up as individual pinpoints of light. But the others blend together to form the bright band of the Milky Way.

The Milky Way shines brightest in summer, because we're looking toward the densely populated center of the galaxy. In fact, the heart of the galaxy lies just above the "spout" of Sagittarius's teapot. That part of the sky contains lots of star clusters, and you can find many of them with binoculars -- more beautiful sights in the awe-inspiring Milky Way.

Script by Damond Benningfield, Copyright 2008

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