From this, Knowing the angle subtended by the ring and knowing the diameter of the ring, we can determine that supernova is 169,000 light-years away. Theoretical models of supernovas had predicted that cobalt 56 would power the light decay curve early in its life. The Solar Maximum Mission satellite andinstruments on National Aeronautics and Space Administration research balloons alsodetected gamma rays from the supernova carrying 847,000 and 1,238,000 electronvolts. It seems that cobalt 57 is now the main radioactive isotope powering the supernova. The observation verified the theoretical prediction, but it did more than that.
Fundamental physics shows that the rate of alpha decay is related to the speed of light.
Since the rates and energies of radioactive decay are the same in the observations of the star 169,000 years ago, we can show that the laws of physics haven't changed for that period of time. By examining the consequences of a faster speed of light in the past, we can determine what we should see in the past. The accidental Universe and that effect on nuclear stability seen in the Chart on page 326 of Barrow and Tiplers' Anthropic Principle. Almost all nuclei would be giving off energy in the form of alpha decay. Thus the light curve should not have decayed at today's decay rates for cobalt 56 and 57.