It’s hard to say what the best constellation of summer is. There are a so many choices, but one of my favorites is Scorpius the Scorpion.
Right now it’s at its highest in our southern skies as evening begins. But that’s not really all that high. The Scorpion is a low-rider with its stinger barely above the horizon — unless you have a really low, flat, treeless southern horizon, you have no chance of seeing Scorpius’s stinger.
I think it’s certainly worth going some place with a low flat horizon to see it. However, it’ll still be a bit of a challenge because it's so close to the horizon and you have to look through a lot more of Earth’s blurring atmosphere to see it. Moderate to heavy light pollution and a lot of humidity in the air add to visual challenge.
If you’re ever in the southern U.S., Scorpius will be a lot higher above the horizon and you can get a much better look at it.
This week, the moon will be almost full, so that will help you find the Scorpion. It will migrate from night to night, eastward above the constellation.
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The bright star Antares is positioned at the heart of the scorpion. It has a dark red, ruddy hue to it and is what astronomers call a "super red giant star." And it’s truly a behemoth.
The Earth is about 8,000 miles in diameter, which is a dwarf compared to the sun, which is nearly a million miles in diameter. The sun, though, is quite small compared to Antares, spanning a diameter of nearly 700 million miles.
If you kicked the sun out of the center of our solar system and replaced it with Antares, then Mercury, Venus, Earth and Mars would be living inside Antares.
While it’s one of the brighter stars in our night sky, it could be a lot brighter if it wasn’t so far away at almost 3,500 trillion miles.
Speaking of Mars, the name Antares is derived from the Greek language which roughly translates to "rival of Mars." Because of its ruddy hue, it can be easily confused with Mars.
Antares demonstrates that stars aren’t just little white lights. Many stars have a slight to distinctive hue to them that can tell you much about their nature.
Just as it is with colors you see in a summer campfires, reddish flames are relatively cooler than blue-ish flames. The sun is a considered a yellowish-white star with the temperature at its outer layer, called the photosphere, and is a little hotter than 10,000 degrees Fahrenheit.
Antares is a bit cooler, just less than 6,000 degrees Fahrenheit. Antares is running out of nuclear fuel in its core. In the next billion years or so, Antares could become so unstable that it’ll blow itself to pieces, becoming the building block of future stars and planets.
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Another interesting star in Scorpius is Graffias, which makes up the head of the scorpion to the upper right of Antares. It’s actually not just one star, but a double star. Even with a good pair of binoculars you can spot them. One of the stars has a lovely bluish-green hue to it, which indicates that it’s a much hotter star than Antares.
For extra credit take a small to moderate-sized telescope and pan it just to the right of Antares. You’ll see what looks like a fuzzy star. That’s actually what astronomers call a globular cluster, a spherical collection of thousands of stars crammed into a ball that's about 200 trillion miles wide.
This giant nuclear family of stars is more than 6,000 light years away. Through a moderate to larger telescope, you might be able to see some of the individual stars at the outside edge of the cluster.
Next week, I'll tell you about the rich lore of Scorpius the Scorpion.
