Accretion disks form when matter with angular momentum falls toward a compact object. Conservation of angular momentum flattens the infalling gas into a rotating disk, while viscosity allows material to spiral inward.
Viscosity: Turbulence from magneto-rotational instability
transports angular momentum outward, allowing mass to spiral in.
Temperature: Friction heats the inner disk to millions of degrees,
producing X-rays from the hottest regions.
Jets: Strong magnetic fields can launch bipolar jets perpendicular to the disk.