Key Terms
- accretion disk
- the disk of gas and dust found orbiting newborn stars, as well as compact stellar remnants such as white dwarfs, neutron stars, and black holes when they are in binary systems and are sufficiently close to their binary companions to draw off material
- black hole
- a region in spacetime where gravity is so strong that nothing—not even light—can escape
- equivalence principle
- concept that a gravitational force and a suitable acceleration are indistinguishable within a sufficiently local environment
- event horizon
- a boundary in spacetime such that events inside the boundary can have no effect on the world outside it—that is, the boundary of the region around a black hole where the curvature of spacetime no longer provides any way out
- general theory of relativity
- Einstein’s theory relating gravity and the structure (geometry) of space and time
- gravitational redshift
- an increase in wavelength of an electromagnetic wave (light) when propagating from or near a massive object
- gravitational wave
- a disturbance in the curvature of spacetime caused by changes in how matter is distributed; gravitational waves propagate at (or near) the speed of light.
- singularity
- the point of zero volume and infinite density to which any object that becomes a black hole must collapse, according to the theory of general relativity
- spacetime
- system of one time and three space coordinates, with respect to which the time and place of an event can be specified
This book was adapted from the following: Fraknoi, A., Morrison, D., & Wolff, S. C. (2016). Key Terms In Astronomy. OpenStax. https://openstax.org/books/astronomy/pages/24-key-terms under a Creative Commons Attribution License 4.0
Access the entire book for free at https://openstax.org/books/astronomy/pages/1-introduction
