Question

What is an accretion disk, and how does one form?

Answer 1

A disk-like structure of spinning debris, such as dust, around an event horizon of a black hole.

Explanation:

They are formed when debris approaches a black hole but doesn't really get engulfed by it. Leaving a layer in the characteristic shape of a disk that is spun due to the black hole's immense gravitational field.

The accretion disks that produce powerful bursts of x-rays and gamma rays are called quasars. These quasars are said to be some of the brightest things in the universe.