The Monster At The Heart Awakes

Just recently I blogged about the 3 to 4 million solar mass black hole sleeping at the center of our galaxy, and how fortunate that is for us. But how certain are we that this thing stays asleep?

The European Space Agency has released a paper that says Japanese researchers think it was awake just recently.

“We have wondered why the Milky Way’s black hole appears to be a slumbering giant,” says team leader Tatsuya Inui of Kyoto University in Japan. “But now we realise that the black hole was far more active in the past. Perhaps it’s just resting after a major outburst.”

They used data from ESA’s XMM-Newton, along with NASA and Japanese X-ray satellites to determine that between 1994 and 2005 hydrogen clouds laying just 300 light-years from the galactic black hole lit up and then faded rapidly in the X-ray part of the spectrum. This means that there was a major event that happened at that black hole at about the time that Shakespeare was writing Hamlet.

Actually, the event happened about 26,000 years earlier, but the light just got here.

If not for the obscuring gas and dust, it would have put on quite a show.

“By observing how this cloud lit up and faded over 10 years, we could trace back the black hole’s activity 300 years ago,” says team member Katsuji Koyama of Kyoto University. “The black hole was a million times brighter three centuries ago. It must have unleashed an incredibly powerful flare.”

Of course, if not for the obscuring gas and dust, it would have fried us too. So what caused this flareup? The black hole probably swallowed a star. Or two. That’s all.

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