The Moon creeps up on the bright star Antares this evening. Depending on your location, you might see them pass less than a degree from each other – less than the width of your finger held at arm’s length. Because the Moon will be so close to Antares, it’ll wash out the star’s reddish orange color.
Astronomers have been tracking that color for thousands of years. And they haven’t seen much change.
Antares is a red supergiant – it’s many times bigger and heavier than the Sun, and tens of thousands of times brighter. Its surface is thousands of degrees cooler than the Sun’s, which is why it looks red.
On the inside, supergiant stars are changing in a hurry – fusing lighter elements to make heavier ones. But the change isn’t always reflected at the surface. In a study a couple of years ago, a team of scientists found that the color of Antares has remained pretty steady for at least 3300 years.
The team analyzed observations from Europe, the Middle East, and China. In China, the star was known as “Great Fire.” In Egypt, it was “red one of the plow.” And many records compared the star to Mars, which is known for its reddish color. In fact, the name “Antares” means “rival of Mars” – a comment on their similar appearance.
The study said the star’s unchanging color could mean that Antares has a good run left before it explodes as a supernova – another million years or longer.
Script by Damond Benningfield