2.3 Space

• A geostationary satellite:

  • remains above the same point of the Earth’s surface.
  • a period of rotation of 24 hours.
  • orbit the Earth 36,000 km above the surface
  • used in telecommunications.
• Polar satellites:

  • have a low altitude
  • orbit around the North and South Pole regions of Earth.
  • They are ideal for collecting climate data as information can be obtained at regular intervals throughout the day.
  • also used for land mapping.
• Satellite Telescopes:

  • can be placed in orbit around the Earth to allow astronomers to obtain amazing images from space.
  • not affected by light pollution or the Earth’s Atmosphere.
• Curved Reflectors:

  • many different types of signals can be transmitted and received by curved reflectors.
  • the curved shape of the reflector ensures that all incoming rays are reflected to the same point.
  • Curved reflectors can be used for transmitting and receiving signals.
• Weak radio signals from space are detected by large curved parabolic dishes.
• data is collected from many parts of the electromagnetic spectrum.

  Each type of radiation requires special telescopes to detect the signals.

  The information collected from using different parts of the electromagnetic spectrum is pieced together to give fuller picture of our Universe.
• Visible light from objects such as stars can be viewed using optical telescopes.
• Refracting Telescope

  Light passes through the wide objective lens. The eyepiece lens magnifies and
• Reflecting Telescope

  large convex mirror is used in a reflecting telescope The convex mirror is used to collect the distant light and is then reflected by a secondary mirror onto the eyepiece lens.
• Benefits of space exploration

  • NASA patented many applications e.g water filters, ear thermometers, scratch resistant lenses, memory foam, shoe insoles, long distance communication, smoke detectors, enriched baby food and cordless tools.
  • development of satellites this has allowed us to make improved observations of our planet.
  • Technology has advanced greatly as a result of satellite information including:
  • Communications - instant, worldwide phones and tv.
  • Position - GPS and Sat Nav to tell you where you are
  • Predicting weather
  • Environmental monitoring
  • Climate monitoring
• Risks of space exploration:

  • Space is a vacuum and humans cannot exist in a vacuum.
  • temperature it can be extremely cold or very hot.
  • Micrometeorites – danger from impact damage
  • Solar flares and radiation – danger from ionising radiations
  • No atmosphere – we need air to breathe
  • Space debris – danger from impact damage
  • Re-entry
• When spacecraft return to Earth they are travelling at high speed. They have a lot of kinetic energy. When they enter the Earth’s atmosphere there is a huge amount of heat generated as the kinetic energy is turned into heat. This heat is caused by the friction between the particles in the atmosphere and the outer surface of the space shuttle.
• Silica tiles can be used to protect the shuttle and the astronauts from the heat generated upon re-entry. The tiles are painted black so that heat is lost to the surroundings. The air around the shuttle heats up so the temperature increase of the shuttle is not as great.
• Planet

  An object which orbits a star
• Star

  A ball of hot gas undergoing nuclear fusion, emitting heat and light
• Galaxy

  Cluster of stars
• Universe

  All of space
• Satellite

  An object in orbit around a planet
• Moon

  A natural satellite
• Solar System

  Consists of a central star orbited by planets.
• 1 light year is the distance that light travels in one year
• Evidence supporting the Big bang theory includes:

  1. Expanding universe
  2. Cosmic Microwave Background Radiation
  3. Abundance of light elements