Determining the Age of the Universe

The vertical axis shows the amount of expansion--given by the average distance between galaxies--since the light was emitted from the supernova. This is calculated from the measured supernova redshifts. The horizontal axis shows the time in the past when a given supernova exploded. The light travel time is calculated from measured supernova distance d (time = distance/speed of light).

The plot above shows observed data from supernovae explosions that occurred in the past 9 billion years. The white dots are data points and the curves are results from calculations using different assumptions about the history of the expansion. The error bars with the white dots indicate the uncertainties in the measurements of time.

From the intersection of the extrapolated curves with the time axis we get the age of the universe. The best fit (red line) gives the best value of the age of the universe of approximately 13.7 billion years!