The solar system consists of:
a star - the Sun
planets and dwarf planets in orbit around the Sun
satellite moons in orbit around most of the planets
comets and asteroids in orbit around the Sun
There are eight planets, including the Earth, and smaller dwarf planets, such as Pluto, Ceres and Eris.
The Sun's gravity keeps the planets, dwarf planets, comets and asteroids in orbit. The gravity of a planet keeps its own satellites in orbit.
The planets take different amounts of time to go around the Sun. A single orbit is called the planet's year, and the further out a planet is the longer its year takes.
The orbits of the planets in the solar system are almost circular – with the Sun near the centre. Many diagrams - including these here - show the orbits very squashed from top to bottom. This is to give a sense of perspective or to fit the diagram to a page.