The planet on which we live is called the Earth. Seen from the Sun, it is the third planet of our solar system and to our knowledge the only one that supports life.
The interior of all of the inner planets, of which the Earth is one, is made up of rock and metal. It is divided into core, mantle and crust.
70% of the Earth's surface is covered by oceans. The appearance of the Earth is changing continuously, by weathering and erosion on the one hand and volcanic eruptions, shifting continental plates and rising mountains on the other.
The Earth is surrounded by an atmosphere, which consists mainly of nitrogen and oxygen. The atmosphere is divided into several sections, which continue out even into space. One of its main functions is to protect the Earth from harmful radiation emitted by the Sun.
The Earth has a constant companion, the Moon. It orbits the Sun while it rotates about is own axis. As the rate of rotation and the rate of revolution coincide, we always see the same side of the Moon. Our satellite appears to us in different phases, which depend on the position of the Sun, Earth and Moon relative to each other.
The surface of the Moon is dominated by numerous plains, highlands and craters. It has neither an atmosphere nor water.
