The scorpion is one of the boldest of all the constellations. Its flat head and curving body and tail are outlined by some of the biggest and boldest stars in the galaxy. But these showy stars won't last long. Within the next few million years, most of them will explode, then fade away.
The constellation is low in the south as night falls this evening. Its leading light is Antares. It forms the scorpion's bright orange heart. The head is to the upper right, while the body and tail curl to the lower left of Antares.
Antares and many of the other stars that form the scorpion's outline are members of a big stellar family known as the Scorpius-Centaurus Association. The stars formed just a few million years ago, when a giant cloud of gas and dust collapsed and broke into dense clumps. The clumps collapsed even more to form stars.
Many of the stars are far heavier than the Sun. Because of that great mass, such a star "burns" through the nuclear fuel in its core in a hurry -- millions of years, instead of the billions of years for stars like the Sun. When the fuel is gone, the star's core collapses to form a neutron star or a black hole, and its outer layers explode as a supernova. For awhile, it shines as brightly as billions of normal stars. But as the explosion dissipates, the star fades away.
Again, look for Scorpius scuttling low across the southwestern sky tonight and through the rest of the summer. More about Scorpius tomorrow.
Script by Damond Benningfield, Copyright 2009
For more skywatching tips, astronomy news, and much more, read StarDate magazine.