University Studies

Portland State University.

Women in American Cosmology. 1) An exploration of the significant role women played in American astronomy over the last 150 years, despite pervasive discrimination in their work-roles, pay, and career choices. 2) Henrietta Levitt's 1908 discovery of the period-luminosity relationship for Chepheid variable stars, a key rung on the Cosmic distance ladder. 3) Wendy Freedman's 1994 observation of Cepheids in a distant galaxy, cutting the age of Universe in half. 4) Finding the age of Universe from its curvature and the galactic distance-velocity relation. 5) Accounting for Large-scale structure.

Discuss "Gender and Science: Women in American Astronomy, 1859-1940," by John Lankford and Rickey L. Savings, Physics Today 43, 58 (March 1990).

Henrietta Levitt and her 1908 discovery of the relationship between the period of the variation and the absolute luminosity of Chepheid variable stars. Cosmic distance ladder.

Cepheid Observed by Wendy L. Freedman using Hubble Space Telescope in the Virgo Cluster placing it at 50 million ly from Earth, half the previous value. Age of universe then half of previous value or 7-11 Billion years.

Edwin Hubble's relationship between galactic recessional velocity and distance. Get the Hubble Constant Ho from the recessional velocity and distance of Virgo Cluster.

Since 1/H_o is a rough upper limit on the age of the universe, the new Hubble constant measurements are implying an universe age of only 12-13 billion years (expanding Supernova photosphere method vs. Cepheid method). This is in conflict with the ages derived for the oldest stars (found in globular clusters) of about 15-16 billion years.

http://universe.colorado.edu/universe/tango/figures.qry?function=number&number=18.01