Hubble Constant


Hubble Constantsearch for term

The present expansion rate of the universe, symbolized by H and measured in units of km/s/Mpc or kilometers per second per megaparsec. In 1929, Edwin Hubble discovered that the Doppler red shifts of other galaxies are directly proportional to their distances from the Milky Way. The constant of proportionality in the relationship is called the Hubble Constant, and it has been measured to be between 50 and 100 km/s/Mpc. In order to check its validity, astronomers use many various observation techniques that each independently derive H.