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