Mars and Antares

The pre-dawn sky might have you seeing red for the next few weeks — or at least reddish orange. That’s because two colorful pinpoints of light will sweep past each other. One of them is Mars, the Red Planet. And the other is its “rival,” Antares — a red-supergiant star.

The two bodies achieve their color in different ways.

Mars is a ball of solid rock, like Earth. Much of its surface is covered by iron-rich dust. Exposure to water has “rusted” the iron, giving it an orangey color.

Antares, on the other hand, is a ball of gas that’s much bigger than the Sun. Its outer layers are quite cool as stars go — a temperature that makes Antares look reddish orange.

The close match in color between the two bodies is what gave Antares its name. “Antares” means “rival of Ares” — the Greek god of war. In Rome, he became known as Mars. So Antares is the rival of Mars. The color of the planet Mars reminded skywatchers of blood, which is why they associated the planet with the war god. And since Antares was about the same color, and Mars regularly passed by it, it made sense to think of the star as being like Mars — a rival for a bright orange planet.

Look for Mars and Antares in the southeast an hour or two before sunrise tomorrow. Mars will stand almost directly above Antares, by less than the width of your fist held at arm’s length. Mars is sliding down to the lower left, so it’ll stick fairly close to its colorful rival for a few weeks.

Script by Damond Benningfield