General

• Galaxy

  The Milky Way galaxy
• Our solar system is part of the Milky Way galaxy
• Planets in our solar system

  Eight (plus the dwarf planets)
• What the planets orbit around

  The sun
• Type of body the sun is

  A star
• Force that pulled together the cloud of dust and gas to form the sun

  Gravitational force of attraction
• Cloud of dust and gas

  A nebula
• Reactions that take place at the start of a star's life cycle

  Fusion reactions
• Factor that determines the type of lifecycle a star undergoes

  The size of the star
• Phases all stars of the same or greater size than the sun undergo

  • Protostar phase
  • Main sequence phase
• What stars of a similar magnitude to the sun become at the end of their life-cycle

  A black dwarf
• What stars much bigger than the sun can become at the end of their lifecycle

  • Neutron star
  • Black hole
• Phases stars of similar size to the sun go through between being a main sequence star and a black dwarf


  • Red giant
  • White dwarf
• Phases stars of greater size than the sun go through between being a main sequence star and a neutron star/black hole


  • Red super giant
  • Supernova
• All of the naturally occurring elements are produced during the fusion processes in a star
• Condition required for fusion reactions to occur in a star

  Very high temperatures
• How elements heavier than iron are produced

  In a supernova
• Type of nuclei that fuse together to form heavier elements in a star

  Hydrogen nuclei fuse to form heavier elements
• How elements are distributed throughout the universe

  Through the explosion of a massive star (supernova)
• What allows planets and satellites to maintain circular orbits

  • Gravity provides the gravitational force that acts as the object's centripetal force
  • The presence of a centripetal force allows for the object to maintain its circular orbit
• Type of satellite a planet's moon can be described as

  A natural satellite
• Examples of artificial satellites


  • TV satellites
  • Satellites used for satellite imaging
• Explain why for a stable orbit, the radius of orbit must change if the speed changes

  1. At higher speeds, the object requires a greater centripetal force

  2. For a greater centripetal force, the gravitational force must increase

  3. This is achieved by the radius of the orbit being reduced
• Explain how the force of gravity acting on a satellite affects its speed and velocity

  1. The force can alter its velocity since the direction is continually changing

  2. It can't cause a change of speed since there is no force component in the direction of motion