Gamma-ray bursts, the most violent cosmic explosions, are the birth announcements for black holes. Several new reports support this increasingly popular notion, but they disagree on how and when the black holes are produced.
According to one theory, known as the collapsar model, gravity rapidly crushes the core of a star at least 20 times as massive as the sun down to a black hole–a superlatively dense cinder whose gravity is so strong not even light can escape its grasp.