• There are many orbiting objects in our solar system and they each orbit a different type of planetary body

Orbiting Objects or Bodies in Our Solar System Table

Gravitational attraction causes the Moon to orbit around the Earth

• Gravity causes different astronomical orbits to orbit certain others
• In general:
  • Planets orbit the Sun
  • Moons orbit planets
  • Comets orbit the Sun
  • Artificial satellites to orbit the Earth or any body in the Solar System

   

Orbits of Planets

• There are several?similarities?in the way different planets orbit the Sun:
  • Their orbits are all?slightly elliptical?(stretched circles) with the Sun at one focus (approximately the centre of the orbit)
  • They all orbit in the?same plane
  • They all travel the?same direction?around the Sun

   

• There are also a few differences:
  • They orbit at?different distances?from the Sun (different orbital radius)
  • They orbit at?different speeds
  • They all take?different amounts of time?to orbit the Sun

   

• The?further?away a planet is from the Sun, the?slower?it travels and therefore the?longer?it takes to orbit

The orbits of planets around the Sun

Orbits of Moons

• Moons orbit planets in a?circular path
• Some planets have more than one moon
• The?closer?the moon is to the planet:
  • The?shorter?the?time?it will take to orbit
  • The?greater?the?speed?of the orbit

   

Comets

• The orbits of comets are very different to those of planets:
• Their orbits are highly?elliptical?(very stretched) or hyperbolic
  • This causes the speed of the comets to change significantly as their distance from the Sun changes
  • Not all comets orbit in the same plane as the planets and some don’t even orbit in the same direction

   

• As the comet approaches the sun, its speed?increases
• As it moves further away from the sun, its speed?decreases

The elliptical orbit of a comet

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