The alleged outburst would rank as the biggest explosion yet discovered in the history of the universe: the energetic equivalent of one billion supernova explosions, unleashed in a torrent that probably lasted 100 million years. A hundred million years of bad space weather.

That is extreme, but it may not be the worst scenario. Ophiuchus is relatively close to Earth, only about 390 million light-years away. If astronomers look farther afield, they might see evidence of equally outlandish events, said Norbert Werner, an astronomer at Masaryk University in Brno in the Czech Republic and at Eotvos Lorand University in Budapest, whose observations with NASA’s orbiting Chandra X-ray Observatory helped lead to the discovery.

A black hole with several billion times the mass of the sun presumably squats at the center of the Ophiuchus cluster, in a galaxy known only by a number, WISEA J171227.81-232210.7.

Black holes are best known for their ability to swallow matter and energy, including light, and remove it from the universe forever. But they have another trait: They belch, and when a black hole belches, you don’t want to be anywhere nearby. Paradoxically, belching black holes are the brightest objects in the universe, producing the fireworks known as quasars and other violent phenomena.

Galaxy clusters are the largest conglomerations of matter in the universe, containing the equivalent of trillions of suns. But most of that matter is in the form of intergalactic gas so hot that it radiates X-rays, which astronomers use to spot clusters far out in space. When this gas cools and sinks to the center of the galaxy, it provides the fuel for outbursts by which a supermassive black hole can affect realms of the cosmos far beyond the originating galaxy.