Moon and Antares

If you gaze into the summer night sky in a million years, it’ll look a lot different than it does tonight. For one thing, the Sun and all the other stars are moving. The change in position isn’t fast enough to notice over a human lifetime, or even many lifetimes, but it adds up. In a million years, many of the stars that are visible now will have moved so far away that they’ll be out of sight. At the same time, other stars will have moved into range.

Another reason for the change is that some stars may no longer exist — they may blow themselves to bits by then.

A leading candidate is Antares, the brightest star of Scorpius. It’s close below the Moon at nightfall. It’s perhaps a dozen times the mass of the Sun, hundreds of times wider than the Sun, and tens of thousands of times brighter.

Antares is only about 15 million years old — a third of a percent of the age of the Sun. Because of its great weight, though, it ages far faster than the Sun does, so it’s already nearing the end of its life.

Before long — perhaps within the next million years — Antares will no longer be able to produce nuclear reactions in its core. The core will collapse to form an ultra-dense neutron star. The star’s outer layers will fall inward, then rebound. They’ll blast out into space, forming a brilliant supernova. As the supernova fades, Antares will disappear from view — one more change in the constantly changing night sky.

Script by Damond Benningfield