In a massive-star supernova explosion, a stellar core collapses to form a neutron star roughly 10 kilometers in radius. The gravitational potential energy released in such a collapse is approximately equal to G M2/R, where M is the mass of the neutron star, R is its radius, and G is the gravitational constant. Using this formula, estimate the amount of gravitational potential energy released in a massive -star supernova explosion. How does it compare with the amount of energy radiated by the Sun during its entire main-sequence lifetime?