A supernova is a rare celestial phenomenon involving the explosion of a star, resulting in an extremely bright, short-lived object that emits vast amounts of energy. The last supernova to be observed in the Milky Way was seen in 1604 by Johannes Kepler and was used by Galileo, at his trial, as evidence against the presupposition that the universe never changes. Visible to the naked eye, it was brighter at its peak than any other star in the night sky. How far from Earth was this supernova? Discuss
Source: The Free Dictionary