Extragalactic astronomy is the branch of astronomy concerned with objects outside our own Milky Way Galaxy. In other words, it is the study of all astronomical objects which are not covered by galactic astronomy, the next level of galactic astronomy.
As instrumentation has improved, more distant objects can now be examined in detail. It is therefore useful to sub-divide this branch into Near-Extragalactic Astronomy and Far-Extragalactic Astronomy. The former deals with objects such as the galaxies of our Local Group, which are close enough to allow very detailed analyses of their contents (e.g. supernova remnants, stellar associations). The latter describes the study of objects sufficiently far away that only the brightest phenomena are observable.
Some topics include:
- Groups and clusters of galaxies
- Quasars
- Radio galaxies
- Supernovae
- Intergalactic stars
- Intergalactic dust
- Intergalactic dust clouds
Famous quotes containing the word astronomy:
“Awareness of the stars and their light pervades the Koran, which reflects the brightness of the heavenly bodies in many verses. The blossoming of mathematics and astronomy was a natural consequence of this awareness. Understanding the cosmos and the movements of the stars means understanding the marvels created by Allah. There would be no persecuted Galileo in Islam, because Islam, unlike Christianity, did not force people to believe in a “fixed” heaven.”
—Fatima Mernissi, Moroccan sociologist. Islam and Democracy, ch. 9, Addison-Wesley Publishing Co. (Trans. 1992)