Milky Way black hole’s last big blast dated to 2 million years ago

A dormant “volcano” — a giant black hole — lies at the heart of our galaxy. Fresh evidence suggests it last erupted two million years ago, astronomers say.  The evidence, they say, comes from a lacy thread of gas, mostly hydrogen, called the Magellanic Stream, trailing our galaxy’s two small companion galaxies, the Large and Small Magellanic Clouds.