Supernovae are among the most violent phenomena in the universe. They are huge explosions that stop the lives of certain types of stars. These explosions release immense amounts of energy,so much that some can be observed from soil with the bare eye, appearing as points of light that are briefly brighter than all the millions of stars in the galaxies where they are found. Following an intense burst of light lasting a few weeks, and supernovae start to fade gradually until they have effectively burned out.
Source: phys.org