Published on 23/09/2013
An artist's conception of a black hole generating a jet. Two million years ago the supermassive black hole at the centre of our Galaxy was 100 million times more powerful than it is today. Credit: NASA/Dana Berry/SkyWorks Digital
A dormant volcano — a supermassive black hole — lies at the heart of our Galaxy. Fresh evidence suggests that it last erupted two million years ago.
Astronomers have long suspected such an outburst occurred, but this is the first time they've been able to date it.