Astronomers theorize that a black hole forms when a massive object shrinks catastrophically under its own gravity, leaving only a gravitational field so strong that nothing escapes it.

天文学家的理论是，当一个巨大的物体在其自身的引力作用下灾难性地收缩，只留下一个强大的引力场，且没有任何东西能逃脱时，黑洞就形成了。