gravity always wins (II).

in general relativity, a black hole is a region of space in which the gravitational field is so powerful that nothing, including light, can escape its pull. the black hole has a one-way surface, called an event horizon, into which objects can fall, but out of which nothing can come. it is called "black" because it absorbs all the light that hits it, reflecting nothing, just like a perfect blackbody in thermodynamics.