Solar System

Our Solar System is made up of the Sun and everything that moves around it. The eight planets orbit the Sun, and Earth is one of them. Our Solar System is alone in space and not connected to other star systems. It all started about four and a half billion years ago when a big cloud of dust and gas fell in on itself. This created the Sun and a spinning disk of material that became the planets.

The Sun is by far the biggest thing in our Solar System. It makes up almost all of the weight. Deep inside the Sun, tiny bits called hydrogen stick together and turn into helium. This makes huge amounts of heat and light that shine out into space. The Sun's light and heat spread throughout the whole Solar System.

The eight planets are the next biggest objects around the Sun. Four planets are close to the Sun and are made of rock. They are Mercury, Venus, Earth, and Mars. Earth and Mars are special because they are in the right place for liquid water to exist on their surfaces. Far away from the Sun are four more planets. Two of them are giant balls of gas called Jupiter and Saturn. Two of them are giant balls of ice called Uranus and Neptune. Jupiter and Saturn together hold almost all the weight of everything except the Sun.

There are also smaller things that go around the Sun. Some are called dwarf planets because they are smaller than regular planets. Pluto is the most famous dwarf planet. Between Mars and Jupiter is a belt full of rocky pieces called asteroids. Far beyond Neptune are icy objects in a region called the Kuiper belt. Even farther out is a giant cloud of icy balls that might be the edge of our Solar System.

Many moons orbit around the planets and other objects. A moon is like a smaller object that goes around a bigger one. Some moons are huge. The biggest moons are even larger than the smallest planet. All around the Solar System, the Sun sends out a wind made of tiny particles. This solar wind spreads out until it meets the space between stars. Our Solar System is moving through a cloud of gas and dust in space. The nearest star to us is very, very far away.