The Solar System (Oxford AQA IGCSE Physics)

The Solar System

• The Sun lies at the centre of the Solar System

  • The Sun is a medium-sized star

• There are 8 planets and an unknown number of dwarf planets which orbit the Sun

  • The gravitational field around planets is strong enough to pull in all nearby objects, except for natural satellites

  • The gravitational field around a dwarf planet is not strong enough to pull in nearby objects

  • There are 4 rocky planets: Mercury, Venus, Earth and Mars

  • There are 4 gas planets: Jupiter, Saturn, Uranus and Neptune

• Some planets have moons which orbit them

  • Moons are an example of natural satellites

• Artificial satellites are man-made and can orbit any object in space

  • The International Space Station (ISS) orbits the Earth and is an example of an artificial satellite

• Asteroids and comets also orbit the sun

• An asteroid is a small rocky object which orbits the Sun

  • The asteroid belt lies between Mars and Jupiter

• Comets are made of dust and ice and orbit the Sun in a different orbit to those of planets

  • The ice melts when the comet approaches the Sun and forms the comet’s tail

Objects in our solar system