Life as we know it wouldn’t exist without the Sun. This ball of gas emits huge amounts of radiation that has sustained life on Earth for millions of years, and it is categorized as a star. Our star is relatively insignificant, as it is one of millions of stars in our galaxy, and our galaxy is only one of the billions of galaxies in the universe. Each of these galaxies are made up of stars that follow similar life cycles. The following activities will introduce students to the cycles of main sequence and massive stars as well as nuclear fusion reactions.