You don't always need fancy instruments to learn something about the stars. Sometimes, your eyes will do just fine.
An example is Spica, the brightest star of Virgo, which is quite near the Moon tonight. If you look at the star carefully, you'll see that it's basically white, with a slight hint of blue. That color tells you that Spica is very hot -- thousands of degrees hotter than the Sun.
Spica is actually two stars that are quite close together. But the stars have about the same surface temperature, which means they have the same color.
A star's color is a direct indication of its surface temperature. The coolest stars look reddish orange, while the hottest look blue. The Sun is somewhere in the middle, so it shines yellow-white.
The temperature can reveal a few other things about a star, too. Blue stars, for example, are not only hotter on the outside, they're hotter inside than most other stars. That's because the stars are more massive. Their gravity squeezes them tightly, heating them up and causing them to "burn" their nuclear fuel at a faster rate. So these stars will live shorter lives than less-massive stars, which have cooler interiors.
Of course, to learn a lot about the details about stars, you need those fancy instruments. But you can get a general idea about them just by looking.
And you can look for Spica near the Moon late tonight. They rise around midnight, with Spica to the lower left of the Moon.
Script by Damond Benningfield, Copyright 2007
For more skywatching tips, astronomy news, and much more, read StarDate magazine.
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