The Solar System is the name we give to our Sun and the planets that orbit around it. Although it is about 12,000 million kilometres in diameter, our solar system is just one of millions of star systems that make up the galaxy called the Milky Way. There are billions of such galaxies in the Universe. The Sun has nine planets in orbit around it. These were formed 4,600 million (4.6 billion) years ago, 400 million years after the Sun was formed. The orbit of each planet follows an individual path, travelling at different speeds yet all in the same direction around the Sun. These planets are kept in their orbit by the force of gravity. Gravity is a force of attraction between any two bodies that have a mass. Its strength depends on the mass of each body and how far apart they are. Planets further from the Sun are less affected by the gravity of the Sun (which accounts for 99% of the mass of our solar system) and therefore travel slower in their orbit. Asteroids (minor planets mostly located between Mars and Jupiter), comets (huge balls of ice) and moons (rocks that orbit planets) together with large quantities of interplanetary dust also form part of the Solar System.
There are some free useful resources available to download from the Science & Technology Facilities Council. You will need to scroll down to find the ones for Primary.
Planets in the Solar System…