If you throw a rock into a still pond, waves ripple outward. They jiggle the leaves and bugs on the surface, shaking things up a bit. And the same thing happens in the stars. In fact, a giant region of the sky is still feeling some “ripples” today.

The Scorpius-Centaurus O-B Association contains many stars of classes O and B – the hottest and brightest stars in the galaxy. It spans hundreds of light-years, and contains thousands of stars. And more stars are being born there today.

The association began as a massive cloud of gas and dust. About 20 million years ago, it produced a big “wave” of starbirth. Many of the newborn stars quickly exploded as supernovas.

That outburst was the “stone” in the pond. Strong winds and shockwaves from the stars rippled outward. That triggered the birth of more stars in the surrounding cloud. The rate of starbirth peaked about 15 million years ago. But the ripples didn’t stop. They created a smaller outburst about 10 million years ago, and another about five million years ago.

Most of the stars in the region are no bigger than the Sun. But a few are big, heavy, and bright – monster stars born from the ripples in a galactic pond.

Many of these monsters are in Scorpius, which is low in the south at nightfall, to the right of the Moon. It’s marked by the scorpion’s bright “heart,” the star Antares – the most prominent member of the Scorpius-Centaurus Association.

Script by Damond Benningfield