Space

• What are comets?

  Ice and dust that orbit the sun in an elliptical orbit
• What are asteroids?

  Rock and metal that orbit the sun in an elliptical orbit. Typically found between Mars and Jupiter
• What is a galaxy?

  A collection of billion stars orbiting one central point.
• What is a satellite?

  Either natural or man-made objects which orbit the Earth.
• What is a natural satellite? Give an example.

  An object which orbits the Earth which is not man-made.

  E.g. The moon
• What is an artificial satellite? Give an example.

  A man-made object which orbits the sun.

  E.g. The international space station.
• Do planets have perfectly circular orbits or slightly elliptical orbits?

  Elliptical
• What is the name of the galaxy that we are a part of?

  Milky way galaxy
• What is the solar system?

  A collection of planets that orbit the sun.
• What is a nebula?

  A collection of gas and dust which creates new stars.
• What happens when a nebula becomes very large?

  Collapses due to gravity and becomes a protostar.
• What happens when a protostar becomes very large?

  It gets very hot and begins nuclear fusion. It will then become a main sequence star.
• What do we call a protostar when nuclear fusion starts?

  A main sequence star.
• Which two forces are balanced in a main sequence star?

  • Outwards force of nuclear fusion
  • Inwards force of gravity
• Which elements undergo nuclear fusion in a main sequence star?

  • Hydrogen
  • Helium
• How long does a main sequence star last?

  Billions of years
• What two things could a main sequence star become once it runs out of hydrogen?

  • Red giant
  • Red super giant

  Depends on how big the star was. If it was small/medium it will become a red giant, if it was big it will become a red super giant.
• For a red giant what are the final stages of a stars cycle?

  White dwarf then black dwarf.
• Which elements can be formed in the red giant or super giant phase?

  Carbon, Oxygen, Nitrogen, Silicon, Magnesium, Neon, Iron, and Nickel
• For a red super giant, what happens next in the star's life cycle?

  Explodes in a supernova.
• Which elements can be formed in a supernova?

  Elements heavier than iron
• What two things can be formed after a supernova? What determines what is formed.

  • Neutron star
  • Black hole

  If it is simply big, it will form a neutron star, if it is a supermassive supernova it will form a black hole.
• What is a neutron star?

  Collapsed core of a red super giant star.
• What is a black hole?

  When the supernova folds in on itself to form a black hole. Gravity is so strong it pulls in any surrounding light, forming a 'gap' in the universe.
• What is an orbit?

  The result of a gravitational force of attraction. What the planets or other celestial objects move around.
• What provides the force that allows planets and satellites to maintain their circular orbits?

  Gravity