Space

• A satellite is any object that orbits another.
• Satellites

  Natural:

  • Moon around Earth
  • Earth around Sun
  • Sun around blackhole in the middle of our solar system

  Man-made

  • Voyager orbiting sun
  • ISS orbiting Earth
  • TV / Weather satellites
• Low Polar orbit

  • Very short period
  • Travels pole to pole (North to South)
  • Can observe every part of the planet over time
  • Relatively close to Earth's surface
  • Used as weather, mapping, spy satellite
• Geostationary orbit

  • Around the equator
  • Orbits once in 24 hours
  • Used for communication satellites
• Low mass star

  1. Nebula - collapse due to gravity producing a protostar.
  2. Protostar
  3. Main sequence star (eg. the sun)
  4. Red giant
  5. Planetary nebula
  6. White dwarf
  7. Black dwarf
• Main sequence star

  When the gas in the nebula starts to come together it will get hot enough for nuclear fusion to start.

  Hydrogen fuses to form Helium, releasing A LOT of energy.

  The star is relatively stable, as the gravitational forces are balanced with the pressure being formed by nuclear fusion.

  Eventually it will run out of Hydrogen to fuse, and begin to fuse Helium, causing the star to expand and cool, becoming a Red giant star.
• Red Giant star

  The gravitational force at the outer layers becomes weaker (due to their size), causing them to lose outer layers to prodcue planetary nebula, leaving behind a white dwarf star.
• White dwarf star

  This is the remanent of the Red giant star, and is VERY hot.

  Eventually it cools to form a black dwarf (much cooler).
• High mass star

  1. Nebula
  2. Protostar
  3. Main sequence star
  4. Red supergiant
  5. Supernova (explosion)
  6. Neutron star OR black hole
• High mass stars

  These larger stars are able to fuse heavier elements, causing them to expand more and become Red supergiant stars.
• Red supergiant stars

  These stars fuse heavier elements, however eventually run out of elements to fuse, and due to the stars mass, all of the outer layers collapse into its core, ricocheting off causing a supernova explosion.

  The remaining star then collapses to form a neutron star or a black hole (which due to its large mass and gravity means that light cannot escape).
• Steady state theory

  • The theory before the Big Bang theory
  • Suggested the universe had no beginning or end
• The Big Bang theory

  'The Universe began form a very small, very dense and very hot initial point. The Big Bang created all matter, energy, space and time.'
• The Doppler effect

  The apparent change in frequencies of sound due to the movement source of the sound.

  Moving away from you = decreasing frequency

  Moving towards you = increasing frequency
• Red Shift


  Light from all far away is red shifted. This shows that the galaxies are moving away from us, suggesting they came from one starting point, supporting the Big Bang theory.
• Hubble used the red shift to calculate the velocities of distant galaxies against their distance from Earth. He concluded that distant galaxies had bigger red shifts, as they were moving away faster.
• CMBR (Cosmic Microwave Background Radiation)


  In the 1960s, Penzias and Wilson discovered that there was microwave radiation coming from all directions of the Universe.

  This radiation is believed to be the heat radiation that is left over from the Big Bang. Supports the Big Bang theory.