Lectures Watched
Since January 1, 2014
1500+ courses starting
in May 2017
Peruse my collection of 263
influential people of the past.
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My Notes on Massive Open Online Course:
Galaxies and Cosmology
An introduction to the modern extragalactic astronomy and cosmology, the physical universe, big bang, formation and evolution of galaxies, quasars, and large-scale structure.
Notes on 2 Lectures I Watched in This Course:
Early History of Cosmology
20th Century Developments in Cosmology
2 People I Have Learned About in this Course:
Charles Messier (1730-1817)
French astronomer notable for publishing an astronomical catalog consisting of nebulae and star clusters
  • Messier was a comet hunter, and was frustrated by objects which resembled but were not comets, so he compiled a list of these objects in collaboration with his assistant Pierre Méchain in order to avoid wasting time on them
  • these 100 objects came to be known as the "Messier objects"
Vesto Slipher (1875-1969)
American astronomer who performed the first measurements of radial velocities for galaxies, providing the empirical basis for the expansion of the universe
  • used spectroscopy to investigate the rotation periods of planets and the composition of planetary atmospheres
  • in 1912, he was the first to observe the shift of spectral lines of galaxies, making him the discoverer of galactic redshifts
  • in 1914, he made the first discovery of the rotation of spiral galaxies
  • in 1929, he discovered the sodium layer, a layer within the Earth's mesosphere of unbound, non-ionized atoms of sodium
  • was responsible for hiring Clyde Tombaugh and supervised the work that led to the discovery of Pluto in 1930