Accretion disk
Definition
An accretion disk is a rotating disk of gas and dust surrounding a massive central object, such as a black hole. It forms as material spirals inward due to gravitational forces and frictional heating causes it to emit electromagnetic radiation.
5 Must Know Facts For Your Next Test
- Accretion disks are often found around black holes, neutron stars, and supermassive black holes in the centers of galaxies.
- The intense heat generated by friction within the accretion disk can cause it to shine brightly in X-rays and other wavelengths.
- Accretion disks play a key role in the growth of black holes by funneling material into them.
- The presence of an accretion disk is one piece of evidence for the existence of black holes.
- In active galactic nuclei (AGN) and quasars, the energy emitted from accretion disks can outshine the entire host galaxy.
Review Questions
- What is an accretion disk and what causes it to form?
- How does friction within an accretion disk affect its properties?
- Why are accretion disks important for understanding black holes and quasars?
"Accretion disk" appears in:
Related terms
Event Horizon: The boundary surrounding a black hole beyond which nothing can escape its gravitational pull.
Quasar: An extremely luminous active galactic nucleus powered by a supermassive black hole with an accretion disk.
Active Galactic Nucleus (AGN): A region at the center of a galaxy that emits tremendous amounts of energy due to matter accreting onto a supermassive black hole.
