Black hole wakes up and has a light snack!

9 April 2013

Astronomers have watched as a black hole woke up from a very long sleep and ate a low-mass object – either a brown dwarf or a giant planet – that came too close. Something similar will soon happen at the black hole at the centre of our own Milky Way Galaxy.

This discovery in a galaxy 47 million light-years away was made by ESA's Integral space observatory. Astronomers were studying a different galaxy when they noticed a bright X-ray flare. "The observation was completely unexpected, from a galaxy that has been quiet for at least 20–30 years," says Marek Nikolajuk of the University of Bialystok, Poland.

The black hole is thought to have a mass of around 300 000 times that of our own Sun. It also likes to play with its food: the way the flare brightened and then faded shows that it took between 2–3 months to completely swallow the object!

The flaring event in this far away galaxy can be seen as a warm-up act for something similar expected in the supermassive black hole at the centre of our own Milky Way Galaxy, perhaps even this year.

While there are no brown dwarfs or planets on the menu this time, a cloud of gas thought to weigh just a few Earth masses has been seen spiralling towards the black hole and is predicted to be swallowed up quite soon.


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