Study: The Milky Way’s Center Exploded 3.5M Years Ago

Researchers find evidence of a cataclysmic flare that punched so far out of the galaxy that its impact was felt 200,000 light years away (via ASTRO 3D)

The center of the Milky Way exploded just 3.5 million years ago.

At least, that’s what researchers at Australia’s ARC Center of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) believe.

A new study led by professor Joss Bland-Hawthorn suggests a colossal beam of energy sprang from near the supermassive black hole at the galaxy’s center, sending a burst of radiation into deep space.

The phenomenon, known as a Seyfert flare, created two enormous “ionization cones” that sliced through the Milky Way, expanding as they exited the star system.

So powerful was the blast, according to ASTRO 3D, that it shook the Magellanic System—a trail of gas extending from the nearby Large and Small Magellanic Clouds—some 200,000 light years away.

The explosion, researchers said, was too big to have been triggered by anything other than nuclear activity associated with black hole Sagittarius A, which is about 4.2 million times more massive than our Sun.

“The flare must have been a bit like a lighthouse beam,” Bland-Hawthorn said in a statement. “Imagine darkness, and then someone switches on a lighthouse beacon for a brief** period of time.”

That’s worse than walking out of a dark cinema in the middle of a sunny day.

Based on data collected by the Hubble Space Telescope, the team calculated that the detonation occurred a little more than 3 million years ago.

In galactic terms, that’s a blink of an eye: By that point on Earth, dinosaurs had been extinct for 63 million years, and humanity’s ancient ancestors—the Australopithecines—were wandering Africa.

“A massive blast of energy and radiation came right out of the [Milky Way’s] galactic center and into the surrounding material,” Lisa Kewley, director of ASTRO 3D, explained.

“This shows that the center of the Milky Way is a much more dynamic place than we had previously thought,” she continued. “It is lucky we’re not residing there.”

Previous research by Bland-Hawthorn ruled out a nuclear starburst as the cause, and tentatively tied it to activity in SgrA*. And while the new work firms up Sagittarius A as a prime suspect, analysts concede there is still “a lot more work” to be done.

A paper—co-written by scientists from ASTRO 3D, the Australia National University, University of Sydney, University of North Carolina, University of Colorado, and the Space Telescope Science Institute in Baltimore—is set to be published in The Astrophysical Journal.

** Up to 300,000 years

More on Geek.com:

• NASA’s Spitzer Captures Vibrant ‘Cosmic Bubble Bath’ in Milky Way
• Milky Way ‘Ate’ a Nearby Dwarf Galaxy 10 Billion Years Ago
• Cool, Gassy ‘Disk’ Spotted Around Milky Way’s Supermassive Black Hole

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