Stars have life spans just like people. High mass stars have
strong gravity making them extremely hot, so they shine very
brightly and exhaust their fuel quickly, within a few million
years. Then they expire in spectacular explosions called supernovae.
Less massive stars like our Sun shine less brightly, but they
last for billions of years. They end their days by ballooning
into a red giant star that eventually blows away its outer
layers and collapses into a stellar cinder called a white dwarf.