A star's whole life in fast-forward
A star is born in a gas cloud, burns steadily for billions of years like our Sun, then swells and dies — some quietly, some in a titanic explosion. Studying different stars is like seeing baby photos and old-age portraits of the same life story.
Furnaces of the universe
Stars shine by nuclear fusion — squeezing hydrogen into helium in their cores, releasing enormous energy. A star lives for millions to billions of years, then, depending on its mass, ends as a white dwarf or explodes as a supernova. A light-year is the distance light travels in one year.
A light-year is a distance
Despite the word 'year', a light-year measures distance — about 9.5 trillion km — not time.
Lab · Fusion fuel
- Identify the fuel a star fuses in its core.
- Name what it becomes.
- Recall where that energy ends up (light and heat).
What you should see: Stars fuse hydrogen into helium, releasing the energy we see as starlight.