Astronomers have discovered the largest explosion in the universe--one that has endured for more than 100 million years and generated as much energy as hundreds of millions of gamma-ray bursts. The source of this mayhem? An apparently insatiable supermassive black hole.

NASA's Chandra X-ray Observatory revealed the eruption, located in a galaxy cluster known as MS 0735.6 + 7421. Specifically, the Chandra images show two cavities, each some 650,000 light-years across, that were scoured out by jets of energy emanating from the black hole, which itself may be a billion times the mass of our sun. Announcing the findings today in the journal Nature, Brian McNamara of Ohio University and his colleagues posit that this enormous release of energy occurred as matter fell into the black hole: most was gobbled up, but some was spewed back out rather violently.

The discovery is unexpected not only because of its record-breaking nature, but because previous work suggested that large black holes don't consume as much matter or grow as quickly as small ones do. "This new result is as surprising as it is exciting," comments co-author Paul Nulsen of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "This black hole is feasting when it should be fasting."