Not long ago, the centre of the Milky Way exploded. Using data from the Hubble Space Telescope researchers calculated it took place 3 and a half million years ago (quite recent in geological terms) – see https://phys.org/news/2019-10-center-milky.html … It is described as a titanic expanding beam of energy that sprang from near the super massive black hole at the heart of our galaxy. It has been labelled the Seyfest Flare which went on to create two enormous 'ionisation cones' that shot through the galaxy and beyond, expanding vastly as it fired away. It was such a powerful flare it impacted the Magellanic Stream – a long tail of gas extending as far as nearby galaxies, the Large and Small Magellanic Clouds. They are 200,000 light years from the Milky Way. A massive blast of energy and radiation came right out of the galactic centre – and the blast or beam of energy is said to have lasted 300,000 years in duration.
At https://phys.org/news/2019-10-dormant-volcano-black-hole-heart.html … we have an update. The headline seems to say the black hole at the heart of the Milky Way is like a volcano – which spat out an enormous flare. It goes on to say the discovery has changed our (their) view of black holes. Activity has been flickering on and off for billions of years we are told. They say they don't understand why this activity is intermittent but it has something to do with how material is dumped into the black hole.