Cassiopeia A Light Echoes in Infrared
Astrophysics (from the Greek: ἄστρον, astron, meaning "star" and Greek: φύσις, physis, meaning "nature") is the branch of astronomy that deals with the physics of stellar phenomena. It is concerned with the physical properties of celestial objects. Studies include the physical characteristics of the stars and other heavenly bodies, their chemical constitution, light, heat, atmospheres, etc. The determination of the amount and nature of the matter present in the universe is an example of important problem currently studied by astrophysics and cosmology. Observations are typically made with the spectroscope, bolometer, and other instruments, usually used with a telescope.
- ↑ Karttunen, H.; Kröger, P.; Oja, H.; Poutanen M.; Donner, K. J, ed. (2003). Fundamental Astronomy (5th ed.). Berlin, Heidelberg, New York: Springer. p. 7. ISBN 978-3-540-34143-7.
- ↑ Jetzer, Philippe (2002). "14: Gravitational lensing". In Bonometto, Silvio;Gorini, Vittorio; Moschella, Ugo. Modern Cosmology. Bristol and Philadelphia: Institute of Physics Publishing. p. 378. ISBN 0-7503-0810-9.