We all know that the core of a galaxy is usually bright due to the high density of stars, but a team of scientists recently discovered that the center of Milky Way was way more bright than it is today. So bright that it sent off a huge flare that traveled more than 200,000 light-years, which means about twice of the galaxy’s diameter.
According to the study, the event happened 3.5 million years ago, which is a blink of an eye for our 13.78 billion years old Cosmos. Even for our planet, which is 4.5 billion years old, that means almost nothing.
The outburst disrupted the Magellanic Stream
The main suspect of the tremendous flare is the nuclear activity from the supermassive black hole present at the center of our galaxy, since it’s the only kind of known phenomenons that could create such powerful outbursts of energy. The flare has been named Seyfert, and it disrupted the Magellanic Stream, a portion of gas left behind by the Small and Large Magellanic Clouds, two dwarf galaxies.
“These results dramatically change our understanding of the Milky Way,” says Magda Guglielmo, co-author of the study. “We always thought about our galaxy as an inactive galaxy, with a not so bright center. These new results instead open the possibility of a complete reinterpretation of its evolution and nature. The flare event that occurred three million years ago was so powerful that it had consequences on the surrounding of our galaxy. We are the witness to the awakening of the sleeping beauty.”
The event lasted for only 300,000 years, which means nothing in terms of an astronomical big picture. The researchers used data provided by the Hubble Space Telescope to be able to confirm the timing and the culprit: 3.5 million years and the supermassive black hole Sagittarius A, respectively.
The study was conducted by researchers at the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), Australia National University, the University of Sydney, the University of North Carolina, University of Colorado and the Space Telescope Science Institute.