1. Approximately one supernova occurs every second. Supernovae happen more often than you might think: one occurs somewhere in the universe every second. However, the Milky Way only has an average of two supernovae per century and trying to spot one as it happens is still very tricky. The last one directly observed in our galaxy was over 400 years ago and its namesake, Johannes Kepler, considered SN 1604 a new type of star at the time.
2. Most chemical elements are made in a supernova. The normal process inside stars, stellar nucleosynthesis, fuses hydrogen to create the elements, from helium through the periodic table to iron. To create the heavier elements through to uranium, however, requires something exponentially hotter and more energetic even than the core of a star – those forces typically found in the instant of a supernova.