This man used Cepheid variables to determine that Andromeda and Triangulum were not part of the Milky Way.  A value named for this man can be represen
This man used Cepheid variables to determine that Andromeda and Triangulum were not part of the Milky Way.  A value named for this man can be represented as the derivative of the scale factor divided by the scale factor. One discovery by this man led Einstein to reconsider his addition of the cosmological constant to general relativity. This man is credited with an equation that gives a linear relationship between velocity and the distance of galaxies. That relation uses the aforementioned value, currently given to be about 70 kilometers per second per Megaparsec. For 10  points, name this American astronomer, the namesake of a famous Space Telescope.
This man used Cepheid variables to determine that Andromeda and Triangulum were not part of the Milky Way.  
Edwin Powell Hubble