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Notes on video lecture:
20th Century Developments in Cosmology
Notes taken by Edward Tanguay on July 11, 2015 (go to class or lectures)
Choose from these words to fill the blanks below:
created, seriously, Nuclei, Microwave, randomly, constant, Coma, straight, Hubble, candles, stellar, curves, redshifts, radars, radio, luminosity, velocities, quasars, Sandage, Virgo, afterglow, 24, superclusters, Zwicky, Laniakea
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dark matter
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Fritz              (1898–1974)
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1933
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Caltech
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realized that the mass of the          Cluster was 400 times the amount of mass in its visible stars
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Sinclair Smith
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1936
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           Cluster
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other astronomers did not take these statements too                    since there was no other evidence for them
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1970s is was accepts when more evidence was found
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from flat galaxy rotation             
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dark matter now plays a key role in models of structure formation
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early galaxy evolution
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Edwin              (1889-1953)
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designed a set of cosmological tests to determine the geometry of the universe
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Hubble diagram
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the plot of distance related to                      of galaxies
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as you go further into space, the line deviates from                 
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Allan                (1926-2010)
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determined the first reasonably accurate values for the Hubble                  and the age of the universe
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discovered the first quasar
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used brightest galaxies as "standard               "
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assuming these were constant
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this failed
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because they are not constants
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they evolve
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stars evolve
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galaxies merge
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so until the mid 1990s, the Hubble diagram was not considered a serious test
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Big Bang Theory
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Ralph Alpher
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George Gamow
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Robert Herman
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predicted the                    of the original hot stage of the universe would be present in the universe as a thermal background
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predicted the abundance of very light elements
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helium, second lightest element
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    % of the total elemental mass of the universe
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discovery of powerful            galaxies
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after WWII thanks to the              technology during the war
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radio astronomy began
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began mapping the sky with radar data
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Walter Baade
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Rudolph Minkowski
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1943 discovery of the Active Galactic             
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Carl Seyfert
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observed bright nuclei in nearby spiral galaxies
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1948 Steady State Cosmology
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proposed by
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Thomas gold
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Hermann Bondi
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Fred Hoyle
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Hoyle did not agree with the Big Bang theory so it was a response to this
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new matter is continuously                as the universe expands
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it is now rejected by the vast majority of cosmologists, astrophysicists and astronomers, as the observational evidence points to a hot Big Bang cosmology with a finite age of the universe
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1963 discovery of               
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first quasars were discovered with radio telescopes in the late 1950s
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many were recorded as radio sources with no corresponding visible object
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quasar
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quasi-stellar radio source
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the most energetic and distant members of a class of objects called active galactic nuclei, or AGN (a compact region at the center of a galaxy that has a much higher than normal                      over some or all of the electromagnetic spectrum, the radiation from AGN is believed to be a result of accretion of mass by a supermassive black hole at the centre of its host galaxy)
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the faster objects recede, the further away they are
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Cyril Hazard
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obtained precise measurements of               
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Allan Sandage
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Maarten Schmidt
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1930s-1980s discovery of the Large Scale Structure
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1930s Zwicky, Shapely began to map how galaxies clump together in space
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clear that they were not                  distributed
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1950s-1980s measurements of                   
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implied distances to vast number of galaxies
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Vaucouleurs
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1950s promoted the idea that galactic clusters are grouped into                           
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our immediate galactic neighborhood forms what he called a supercluster
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was indication of structures that were larger than anything seen before
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the Milky Way is in the Local Group of galaxies, which in turn is in the                  Supercluster
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the Virgo Supercluster is an appendage of the Laniakea Supercluster
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1965 discovery of Cosmic                    Background
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Arno Penzias
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Robert Wilson
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Nobel Prize, 1978
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provided evidence for the Big Bang theory
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today we can measure it with space instruments
Early History of Cosmology
20th Century Developments in Cosmology