Astronomers have long realized that supernovae - when they explode - give off an enormous amount of light. But observations of Supernova 1987A (in the Large Magellanic Cloud) and subsequent supernova detection from other galaxies have revealed that a supernova gives off even more energy in another form? That form is:
a) Gravitational waves
b) X-rays
c) Neutrinos
d) Gamma rays