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Astro*Dictionary by Michael Erlewine





2 articles for "Absorption"

Absorption Line [Astro*Index]

Used in studying the evolution of the cosmos, an absorption line is produced by a galaxy or interstellar gas in the path of a quasar's radiation. The light from a bright, continuous-spectrum source shines through the gas or galaxy whose temperature is lower than that of the source. The dark absorption lines appear in the positions characteristic of the cooler gas. The cooler gas absorbs from the beam of light only those rays that it normally emits. Absorption lines allow dimmer objects, themselves at great distances from the Earth, to be observed. Since it is not always certain what form of intervention exists, the use of absorption lines in evolutionary cosmology has been a source of dispute among astronomers.

See also:
♦ Light Spectrum ♦ Quasar
Absorption Nebula [Astro*Index]

A collection of interstellar dust which obscures the light of distant background stars. Also called dark nebula.

See also:
♦ Nebulae


Astro*Index Copyright © 1997 Michael Erlewine