The solar system is made up of the Sun and the objects moving around it at very high speeds. The Earth and 8 other planets revolve around the Sun in very large, smooth paths called orbits. There are also many very large rocks that revolve around the Sun. A moon is a natural satellite that moves around a planet, much like the planet itself moves around the Sun. Our Earth only has one moon.
Some planets have several moons.
The Sun is a giant ball of hot burning gases, which keeps our planet warm. The Sun is a star. It is the only star in our solar system. Outside the solar system is the rest of our galaxy, which is named the Milky Way galaxy. It is thousands of degrees hotter than it is here on Earth.