The black hole at the center of the Milky Way Galaxy is a light eater – at least it is today. But 200 years ago, it could’ve had a feast. That would have made it shine hundreds or thousands of times brighter than it is today.

The black hole is called Sagittarius A-star. It’s more than four million times the mass of the Sun. That’s actually pretty small for a black hole in a galaxy as big as the Milky Way.

Like all supermassive black holes, it’s encircled by a disk of gas. Some of that material funnels into the black hole. As it does, it gets hot enough to shine at many wavelengths, including X-rays. How bright it gets depends on the mass of the disk – how much stuff the black hole is eating.

Today, the X-ray glow is fairly steady, but faint. But a space telescope has detected some X-ray-bright areas a couple of hundred light-years from the black hole. Those areas could have been illuminated when the black hole flared up about 200 years ago. The black hole might have wolfed down an unlucky asteroid or a small cloud of gas and dust – a feast for the black hole, accompanied by a short but bright flare-up.

The black hole is in Sagittarius, which is in the southern sky on summer evenings. Its brightest stars form the outline of a teapot. The black hole is above the spout of the teapot, but it’s hidden behind clouds of dust – 27,000 light-years away.

More about Sagittarius tomorrow.

Script by Damond Benningfield