Our Solar System contains 8 planets in all. The four planets closest to the Sun (Mercury, Venus, Earth, Mars) are called the terrestrial planets because they have a solid rocky surface. The four largest planets (Jupiter, Saturn, Uranus, Neptune) are called the gas giants because they are big and mostly made of gas. As well as the 8 major planets in the Solar System there is also a tiny dwarf planet called Pluto. Pluto also has a solid surface like the terrestrial planets, but it is made mostly from ice instead of rock.
All of the planets orbit the Sun in the same counter-clockwise driection. Due to their varying distances from the Sun, some complete each orbit quicker than others. The terrestrial planets, which are closer to the Sun, orbit quicker than the gas giants,
Most of the planets have an atmosphere. Earth's atmosphere is mostly nitrogen and oxygen. Mars and Venus have an atmosphere made mostly of carbon dioxide. Jupiter, Saturn, Uranus, and Neptune are mostly made of hydrogen and helium.
Many of the planets in our Solar System have their own moons. There are over 160 moons in total, all orbiting around their parent planets. Planets like our Earth have only 1 moon, while the gas giant planets Jupiter and Saturn have over 60 moon each. You can see find more information on some of the Solar System moons in the "Moons and Probes" section of our website. You can even see some spaceprobes landing on them!