Milky Way's monster black hole awoke 300 years ago
AFP on Yahoo ^ | 4/15/08 | AFP

PARIS (AFP) - A black hole slumbering at the centre of our galaxy went into a "feeding frenzy" three centuries ago, the European Space Agency (ESA) said on Tuesday.

Located around 26,000 light years from Earth, the black hole, known as Sagittarius A-star (Sgr A*), is a monster with a mass four million times that of the Sun.

Japanese astronomers, using ESA's XMM-Newton orbital telescope and US and Japanese X-ray satellites, discovered that clouds of gas brightened and faded in X-ray light when they passed near Sgr A*'s maw, ESA said in a press release.

The phenomenon is due to X-ray pulses that are believed to be residual bursts from a flare that happened 300 years ago.

"We have wondered why the Milky Way's black hole appears to be a slumbering giant," team leader Tatsuya Inui of Kyoto University said.

"But now we realise that the black hole was far more active in the past. Perhaps it's just resting after a major outburst."

One theory is that a few centuries ago, the powerful gravitational pull of the black hole engulfed clouds of gas from an exploding star called a supernova, ESA said.

The "temporary feeding frenzy" caused X-ray energy to leap from its mouth in a giant flare.