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 the Milky Way. They thought this because they could only see the planets up to Saturn and stars. With the invention of the telescope, our universe got bigger. Even in the 20th century, people thought that the Milky Way was the universe. With the Hubble Space Telescope, people could see things far away.
- "Definition of COSMOLOGY". www.merriam-webster.com.
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- "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.