Hubble constant

In astronomy, measure of the rate at which the universe is expanding, named after US astronomer Edwin Hubble. Observations suggest that galaxies are moving apart at a rate of 50–100 kps/30–60 mps for every million parsecs (megaparsecs) of distance. This means that the universe, which began at one point according to the Big Bang theory, is between 10 billion and 20 billion years old. Observations by the Hubble Space Telescope in 1996 produced a figure for the constant of 73 kps/45 mps per megaparsec. Measurements of the cosmic background radiation currently give a value close to 70 kps/43.5 mps per megaparsec.