How have scientists determined the age of the universe? Well, the redshift data helped. If you recall from an earlier tutorial, Hubble tweaked the redshift data to communicate the recessional velocity of the stars. In other words, he calculated, based on the redshift data, how quickly the stars seem to be moving away from us. He then plotted the recessional velocities on the y axis against distance from Earth on the x axis. The slope of the line produced from this data is referred to as the Hubble Constant, and is given the symbol Hg. This number is still under dispute, but is thought to be somewhere around 70km/s/Mpc (70 kilometers per second per megaparsec). This value provides the rate of expansion of the universe. The inverse of this constant offers on estimate of the age of the universe.Calculate it for yourself - what is the approximate age of the universe?

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