How Are Stars Born, Live, and Die?

The spoken lesson

"Stars begin in cold clouds of gas and dust. Gravity pulls dense regions together, forming protostars. When a core becomes hot and dense enough for sustained hydrogen fusion, the star enters its main-sequence life. A star's mass strongly shapes what happens next. A Sun-like star expands into a red giant, releases its outer layers, and leaves a white dwarf. The Sun is not massive enough to become a supernova. Much more massive stars can become supergiants, collapse, and explode as supernovae, leaving neutron stars or black holes under suitable conditions. Stars create and disperse elements that later become part of new stars, planets, and living things. A star's mass shapes its lifetime, final stages, remnant, and contribution to future cosmic material." DESIGN REQUIREMENTS: Use a branching lifecycle, not one universal circle. Show realistic timescales and mass dependence. Avoid Sun-supernova imagery, every-star-black-hole claims, frightening destruction, or an individual star looping back into itself.