1. Edwin Hubble (1889 - 1953) Biography American astronomer Education: University of Chicago First to show other galaxy by photographing stars of Andromeda Discovered the expansion of the Universe (Hubble Law) by observing the red-shifts of galaxies. Contributor: Mike Chu – Spring 2013, Montgomery College, Germantown http://cosmology.carnegiescience.edu/timeline/1929http://cosmology.carnegiescience.edu/timeline/1929 ???

2. The prevalent view of the time was that the Milky Way was the sole star system in an empty space “Andromeda Nebula” was but a faint patch Hubble photographed Andromeda and identified stars and Cepheid variables. Hubble estimated the distance to be (????) (Comment: Add a picture) 1923-24 Observations of Andromeda References: 1.Horizons by Michael Seeds, Chapter 12 ??? 2.Wikipedia: ???

3. Hubble Expansion Hubble worked at Mount Wilson Observatory (1919 -?) Vesto Slipher had already done some observations of galaxies (call “nebula” at the time?)  Showed that the recession velocity of galaxies is proportional to distance:  v = H d where H is Hubble Constant  Measured H=500 (km/s)/Mpc – 500 km/s for every Mpc  Concluded that universe is expanding  Over-estimated the value by 7 to 8 times (Comment: add original plot and a modern update)

4. Addendum (for students)

5. Early modern astronomy techniques, e.g. photographic plates Early modern large ground-based telescopes, e.g. Mount Wilson Observatory (a documentary is available on PBS.org) Prediction and history of Hubble Constant The expansion of the universe Follow-up topics (for mid- and long- presentation)