All objects are attracted towards each other by a force called gravity. Gravity only becomes noticeable when there is a really massive object like a star, planet or moon. You can find out more about gravity in the Revision Bite called Forces.
Gravity and the solar system
Gravitational forces between the Sun and planets keep the planets in orbit around the Sun. Without these forces, the planets would fly off into deep space.
Their orbits are slightly squashed circles called ellipses. Diagrams often…