Astrophysics

• Universe

  large collection of billions of galaxies
• galaxy

  large collection of stars
• Force that keeps stars together

  gravity
• Solar system in the size order

  1. Planets
  2. Dwarf Planets
  3. Moons - type of natural satellites
  4. Artificial satellites
  5. Asteroids - lumps of rock and metal found in the asteroid belt
  6. Comets - lumps of ice and dust. highly ELLIPTICAL
• Instantaneous velocity


  Force that stops the object accelerating towards what it is orbiting but instead makes it travel in a circle
• The closer the object gets to the star or planet, the stronger the gravitational force is
• The stronger the force the larger the instantaneous velocity needed to balance it so it needs to go faster to remain in orbit
• Orbit of moons and planets

  slightly elliptical
• Orbit of comets


  very elliptical, longer than earth as they travel from the outer edges of our solar system. Faster when it is nearer the sun because the increased pull of gravity makes it speed up the closer it gets to the sun
• Stellar Evolution order

  1. Nebula
  2. Protostar
  3. Main sequence star
  4. Red Super Giant (for stars bigger than the sun)
  5. Supernova
  6. Neutron star or black hole

  4. Red giant

  5. White dwarf
• Nebula

  cloud of dust and gas
• Protostar

  gravity pulls dust and gas together. Temperature roses so star gets denser and more particles collide with each other. When temperatures get high enough the hydrogen nuclei undergo nuclear fusion to form helium nuclei. This gives out energy which keeps the core of the star hot.
• Stars, temperatures and colours (Hottest to coolest)

  1. Blue
  2. White
  3. Yellow
  4. Orange
  5. Red