A high-mass star starts out its life as a luminous main sequence star, and also later becomes a red giant. Instead of collapsing and fading into a white dwarf, however, it fuses not only hydrogen into helium, but also helium into carbon, carbon into oxygen, and so forth. This creates heavier and heavier elements, including neon, magnesium, silicon, and iron. Then, when the equilibrium between the inward pull of gravity and the out ward push of nuclear fusion energy is broken, the star’s own gravity collapses the core of the star in a tiny fraction of a second, blowing itself apart in a titanic explosion called a supernova. The final remnant of this evolutionary path is a neutron star. A neutron star is the collapsed stellar core and is only about ten miles across, yet several times more massive than the Sun. A high-mass star that contains about ten times the Sun’s mass, in fact, would be about one thousand times more luminous during its main sequence and would have a main sequence lifetime of about one hundred million years.