MEPX
Chapter 9 of 12All chapters
  1. 1The scale of things
  2. 2The Sun
  3. 3The rocky planets
  4. 4The giant planets
  5. 5Moons
  6. 6Asteroids and comets
  7. 7Gravity and orbits
  8. 8Light and distance
  9. 9Stars and their lives
  10. 10Galaxies
  11. 11The expanding universe
  12. 12Observing for yourself

Chapter 9 of 12

Stars and their lives

Born in clouds, ending in several ways.

How they live

A star forms when a cloud of gas collapses until fusion starts in the core. It then spends most of its life balancing that outward pressure against its own gravity.

  • Colour tells you temperature: blue stars are hot, red stars are cool.
  • Bigger stars burn far faster and live far shorter lives.

How they end

A star like the Sun swells into a red giant and settles as a white dwarf. Much heavier stars explode as supernovae and leave a neutron star or a black hole, scattering the heavier elements that everything else is made of.