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If a black hole's gravity is so great that not even light can escape its pull, why do some black holes, like quasars, emit jets of material?

BEN HANSELL, SAN FRANCISCO
Black holes are regions where matter is extremely, mind-boggingly compressed into zero volume. According to Einstein's theory of general relativity, neither matter nor light can escape these dense objects. Hence, they are called black holes. However, the distance a black hole's strong gravity reaches is limited and is called the event horizon. Light is not emitted from the black hole itself but from an accretion disk of gas and dust that forms around a black hole far from its event horizon.

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