space

• life cycle of a sun sized star:

  1. nebula
  2. protostar
  3. main sequence star
  4. red giant
  5. white dwarf
  6. black dwarf
• life cycle of a bigger star

  1. nebula
  2. protostar
  3. main sequence star
  4. red super giant
  5. supernova
  6. black hole (if big enough)
  7. neutron star
• protostar

  a spiral of gas and dust

  • lots of gravitational attraction which increases density
  • more frequent particle collisions so the temperature increases
  • when the temperature is high enough, hydrogen nuclei undergo nuclear fusion which forms helium nuclei
  • these give off lots of energy, keeping the core hot so a star is born
• nebula

  a cloud of dust and gas
• main sequence star

  long stable period of several; billion years until hydrogen runs out
• white dwarf star

  hot, dense core that keeps loosing energy
• supernova

  ejects elements to form new planets and stars
• neutron star

  very dense supernova core when all the outer dust and gas layers are gone
• black hole

  a super dense point in space that not even light can escape