space

• Planet


  A rocky or gaseous body, usually spherical, which orbits a central star. Reflects light from stars but does not produce its own light.
• Dwarf planet


  An object which orbits a star but is too small to classify as a planet and too large to classify as an asteroid
• Moon


  A rocky body which orbits a planet. Reflects light from stars but does not produce its own light.
• Asteroid


  A rocky body which orbits a star, but is too small to be classified as a planet, or orbits a planet and is too small to be classified as a moon. Unlikely to be spherical in shape.
• Star


  A massive ball of gas which is undergoing nuclear fusion. Produces vast quantities of light and heat through this process.
• Solar System


  A system consisting of a central star and all objects which are gravitationally bound to it, including planets (and their moons), asteroids and comets.
• Exo-planet


  A planet which is in orbit around a star other than our own.
• Galaxy


  A collection of several million stars and their planets, gravitationally bound and moving through the Universe as a single system.
• Universe


  Everything we know to exist everywhere, all stars, planets, galaxies and their contents.
• Distance


  Distances in space are huge. Even a trip to Mars would require at least 3 months just to travel there, that doesn't include the return trip or any time spent on the planet!
• Possible solution to reduce expedition duration

  • Reach large velocities by using an ion drive (producing a small unbalanced force over an extended period of time)
• Velocity


  The velocities required can be difficult to obtain
• Slingshot/catapult methods


  Using the gravitational field of a planet, moon or asteroid to accelerate the spacecraft, reducing fuel requirements
• Ion drive


  • Provides a small but constant acceleration throughout the journey allowing for a gradual build up to a large velocity
• Manoeuvring


  There is no friction in space (and so an object in motion will stay in motion). Additionally, all objects in space will be moving relative to one another, therefore any delicate manoeuvres, such as docking with the ISS must be done extremely carefully, with thrusters required to stop as well as start motion in a straight line or even to cause rotation.
• Energy


  Energy supplies are limited in space, so spacecraft and satellites must be self-sufficient, ensuring that life support systems remain in constant operation
• Achieving self-sufficiency


  Use of arrays of solar cells, which convert light energy from the sun into electrical energy
• examples of problems to space travel ; enough velocity, large distances, maneuvering, gaining enough energy
• risk of space travel; radiation, solar flares, micrometeorites, space junk, re-entry heat, no atmosphere, fuel
• newtons third law: object A exerts a force on object B then object B exerts an equal and opposite force on Object A
• The universe is estimated to be approximately 13.8 billion years old.
• big bang theory - the universe began as a single point with infinite density and temperature