Cosmology is the branch of astronomy that deals with the origin, structure, evolution and space-time relationships of the universe. NASA defines cosmology as "The study of the structure and changes in the present universe". Another definition of cosmology is "the study of the universe, and humanity's place in it".
Though the word cosmology is recent (first used in 1730 in Christian Wolff's Cosmologia Generalis), the study of the universe has a long history.
Until recently, people thought that the universe was only the Milky Way galaxy. They thought this because they could only see the planets up to Saturn and stars. With the invention of the telescope, we could see more of the universe. Even in the 20th century, people thought that the Milky Way was the entire universe. With the Hubble Space Telescope, people could see things far away.
Modern cosmology is considered to have started in 1917 with the final paper of Albert Einstein's theory of general relativity. This paper was known as "Cosmological Considerations of the General Theory of Relativity" which made physicists start to change the assumption that the Universe never changed. When a scientific discipline begins to change an idea that is believed by many people, it is known as a paradigm shift. During this paradigm shift, the Great Debate took place. Many scientists debated if there were other galaxies. The debate ended when Edwin Hubble found Cepheid Variables in the Andromeda Galaxy in 1926.
The Big Bang model was then created by Belgian priest, Georges Lemaître in 1927. This was supported by Edwin Hubble's discovery of the redshift in 1929 and later by the discovery of cosmic microwave background radiation. This was found by Arzo Penzias and Robert Woodrow Wilson in 1964.
All of these discoveries have been further supported throughout the 20th century. Some more observations of the cosmic microwave background radiation were found by the COBE, WMAP, and Planck satellites. Some more observations of the redshift were found by the 2dfGRS and SDSS. These are known as redshift surveys. Survey is this context refers to an astronomical survey. An astronomical survey is a place in space. A redshift survey is a survey that looks for redshifts.
On 1 December 2014, at the Planck 2014 meeting in Ferrara, Italy, astronomers reported that the universe is 13.8 billion years old and is composed of 4.9% regular matter, 26.6% dark matter and 68.5% dark energy.
- "Definition of COSMOLOGY". www.merriam-webster.com.
- Daintith, John; Gould, William (2012) . Collins Dictionary of Astronomy (Fifth ed.). HarperCollins. p. 96. ISBN 9780007918485.
- "NASA education" (PDF).
- "Christianity: beliefs about creation and evolution". BBC. Retrieved 2011-11-03.
- "cosmology - Definition of cosmology in English by Oxford Dictionaries". Oxford Dictionaries - English. Archived from the original on 2019-03-21. Retrieved 2019-02-11.
- Einstein, A. (1952). "Cosmological considerations on the general theory of relativity". The Principle of Relativity. Dover Books on Physics. June 1: 175–188. Bibcode:1952prel.book..175E.
- "The Structure of Scientific Revolutions. By <italic>Thomas S. Kuhn</italic>. (Chicago: University of Chicago Press. 1962. Pp. xv, 172. $4.00.)". The American Historical Review. April 1963. doi:10.1086/ahr/68.3.700. ISSN 1937-5239.
- Falk, Dan (March 2009). "Review: The Day We Found the Universe by Marcia Bartusiak". New Scientist. 201 (2700): 45. doi:10.1016/s0262-4079(09)60809-5. ISSN 0262-4079.
- Hubble, E. P. (December 1926). "Extragalactic nebulae". The Astrophysical Journal. 64: 321. doi:10.1086/143018. ISSN 0004-637X.
- Martin, G. (1883). "G. DELSAULX. — Sur une propriété de la diffraction des ondes planes; Annales de la Société scientifique de Bruxelles; 1882". Journal de Physique Théorique et Appliquée. 2 (1): 175. doi:10.1051/jphystap:018830020017501. ISSN 0368-3893.
- Hubble, Edwin (1929-03-15). "A Relation Between Distance and Radial Velocity Among Extra-Galactic Nebulae". Proceedings of the National Academy of Sciences of the United States of America. 15 (3): 168–173. doi:10.1073/pnas.15.3.168. ISSN 0027-8424. PMC 522427. PMID 16577160.
- Penzias, A. A.; Wilson, R. W. (July 1965). "A Measurement of Excess Antenna Temperature at 4080 Mc/s". The Astrophysical Journal. 142: 419. doi:10.1086/148307. ISSN 0004-637X.
- Boggess, N. W.; Mather, J. C.; Weiss, R.; Bennett, C. L.; Cheng, E. S.; Dwek, E.; Gulkis, S.; Hauser, M. G.; Janssen, M. A. (October 1992). "The COBE mission - Its design and performance two years after launch". The Astrophysical Journal. 397: 420. doi:10.1086/171797. ISSN 0004-637X.
- Parker, Barry (1993). The Vindication of the Big Bang. Boston, MA: Springer US. pp. 129–157. doi:10.1007/978-1-4899-5980-5_6. ISBN 978-0-306-44469-2.
- "Computer Graphics Achievement Award". ACM SIGGRAPH 2018 Awards. New York, NY, USA: ACM: 1. 2018-08-12. doi:10.1145/3225151.3232529. ISBN 978-1-4503-5830-9. S2CID 51979217.
- "NETWATCH: Botany's Wayback Machine". Science. 316 (5831): 1547d. 2007-06-15. doi:10.1126/science.316.5831.1547d. ISSN 0036-8075. S2CID 220096361.
- Paraficz, D.; Hjorth, J.; Elíasdóttir, Á. (2009-03-19). "Results of optical monitoring of 5 SDSS double QSOs with the Nordic Optical Telescope". Astronomy & Astrophysics. 499 (2): 395–408. doi:10.1051/0004-6361/200811387. ISSN 0004-6361. S2CID 7866444.
- "New York Times Survey, December 1985". ICPSR Data Holdings. 1987-10-12. doi:10.3886/icpsr08690. Retrieved 2021-01-28.