Final answer:
The material in an accretion disc is drawn toward a black hole due to gravitational forces, spiraling inward and heating up to emit X-rays. Some of it can be ejected in high-speed jets perpendicular to the disc, while smaller bodies within the disc undergo a critical growth period to evade frictional drag.
Step-by-step explanation:
The material moves inward through an accretion disc that forms around black holes or other astronomical objects due to the mutual revolution of the object and nearby matter like gas, dust, or stars. The gravitational attraction of the black hole pulls in matter from its surroundings; this matter then spirals inward, forming a rotating disc. As the material travels closer to the black hole, it accelerates and experiences increased compression and internal friction, which can heat the matter to extreme temperatures, leading to the emission of X-rays. In some cases, the pressure and speed are so tremendous that part of the inward-bound material can be expelled in narrow beams perpendicular to the disc, especially with faster accretion rates and thicker discs.
This process resembles how a baby tries to eat by herself, where not all food makes it into her mouth but can be pushed out in other directions. Similarly, the accretion disc's matter under high pressure and speed can be ejected outwards. For smaller bodies within the disc, such as dust grains growing into planetesimals, there is a perilous stage of growth where they must become sufficiently large or face being slowed and eventually falling inward due to frictional drag forces within the gas of the disc.