A typical supernova can produce as much light and other forms of electromagnetic radiation as billions of stars. Electromagnetic radiation is energy carried through space by electric and magnetic waves. The length of these waves determines the properties of the radiation. In addition to the radiation energy a supernova produces, the force of the explosion releases ten times more energy into the motion of the particles that the explosion blows outward. These tiny particles, called neutrinos, carry away a hundred times more energy than the electromagnetic radiation.
Astronomers discover about ten supernovas in distant galaxies each year.
The mass of a star determines whether it will end its life in a supernova explosion. During the courses of their lifetimes, all stars convert hydrogen to helium in thermonuclear fusion reactions in their cores . Thermonuclear fusion reactions occur when the intense heat and gravitational force in a star's nucleus force hydrogen atoms together. The atoms merge, or fuse together, creating helium atoms and releasing large amounts of energy in the form of electromagnetic radiation and heat. Massive stars have faster rates of fusion than smaller stars, so large stars may use up their fuel faster.