You are here


July 21, 2016

A beautiful and well-known constellation skitters low across the south on summer nights. It forms a distinctive hook shape, and its leading light is quite bright, so it’s easy to pick out. And it’s especially easy to find this year because two bright planets are just outside its borders.

Scorpius represents a scorpion, and it’s easy to see why. Several moderately bright stars outline a curving body that ends with a barbed stinger. And a row of stars at the top of the body forms the head. So once you find Scorpius for yourself, you won’t have any trouble coming back to it.

The scorpion’s brightest star is Antares — one of the most impressive stars in our region of the galaxy. It’s a red supergiant — it’s hundreds of times wider than the Sun, and tens of thousands of times brighter. But its surface is cooler than the Sun’s, so it looks bright orange.

Much of the scorpion’s body and tail are enwrapped in the glow of the Milky Way — the combined light of millions of stars in the disk of our home galaxy. And several bright star clusters reside within the constellation’s borders.

And right now, Mars and Saturn flank those borders. Saturn stands above Antares at nightfall. And even-brighter Mars is to the upper right of Antares, shining with the same orange color. In fact, that’s how Antares got its name. The name means “rival of Mars” — a name bestowed because its color is almost identical to the Red Planet’s.

More about Scorpius tomorrow.

Script by Damond Benningfield

Get Premium Audio

Listen to today's episode of StarDate on the web the same day it airs in high-quality streaming audio without any extra ads or announcements. Choose a $8 one-month pass, or listen every day for a year for just $30.