space

• Heliocentric


  Our planet is not the center of the universe as it orbits the sun
• Components of the solar system

  • Sun
  • Planets
  • Dwarf planets
  • Moons
  • Comets
  • Asteroids
• Formation of the sun

  1. Clouds of gas and dust collapsing, forming a protostar

  2. Materials colliding until temperature and pressure high enough to fuse and form helium

  3. Entering the stable main star sequence
• Moons


  Natural satellites that have entered the orbit of a planet
• Comets and asteroids


  Icy bodies, rocks and other substances that orbit around the sun
• Life cycle of a star

  1. Nebula stage - dust and gas drawn together by gravity, fusing

  2. Stable star stage - thermal energy from fusion makes star expand, balanced by gravity

  3. Running out of hydrogen fuel stage - star expands into red or giant red star
• Smaller stars


  • Turn into white dwarfs, then black dwarfs
• Larger stars


  • Explode, creating a supernova, leaving a neutron star or black hole
• Creation of elements


  1. Small stars fuse hydrogen into helium

  2. Large stars fuse hydrogen into lithium and light metals

  3. Supernovae produce energy to fuse hydrogen into elements heavier than iron
• Satellites


  Can be natural or manmade, go in circular motion due to gravity
• Satellite speed and radius

  If speed changes, radius of orbit changes
• The sun is one of 200-400 billion stars in the Milky Way, with an estimated 100 billion planets orbiting these stars</b>
• The Milky Way is estimated to be 100,000 light years wide
• There are estimated to be 200 billion galaxies in our universe, each with their own billions of stars and planets
• Due to the size of the universe, there is probably other intelligent life out there, but it is near impossible to communicate with them as they are too far away
• Redshift


  Wavelength of light from distant galaxies is stretched, as they are moving away from us
• Redshift


  The further away a galaxy, the faster it is receding, the greater the redshift
• Evidence from observing supernovae proves that the further a galaxy is, the faster it is receding
• Redshift and Big Bang theory

  The fact that galaxies are moving away proves they all started in a dense place that exploded, supporting the Big Bang theory and expanding universe
• Scientists do not know how galaxies are expanding or what dark matter and dark energy are