If you put enough matter (1) in one small place, it creates a black hole(2), a gravitational field (3)so intense that nothing, not even light, can escape from (4) it.
A black hole is an extremely weird object. Its intense gravitational field changes space and time in fundamental ways. Each black hole has only three measurable properties (5) : mass (6), electrical charge (7), and rotational momentum (8).
Most astronomers now believe that there is a stupendously huge black hole in the inner core of our galaxy, billions of times heavier than the sun. It spins (9) in the center of a rotating whirlpool (10) of hot gas and dust, slowly sucking (11) it in.
(5) 明显的 组成部分