Our solar system consists of a central star (the Sun), and the different celestial bodies that orbit it. Our solar system is thought to be approximately 4,6 billion years old.

The solar system was formed when the substances that floated freely in space slowly accumulated and compressed, forming the Sun and the eight planets that orbit it. Over 99,9 % of the solar system's total mass is located in the Sun. The Sun's gravity keeps the eight planets orbiting around it.


The solar system. Notice the asteroid belt between Mars and Jupiter. The Kuiper zone, located near the edge of our solar system, contains even more asteroids.

The closest planets to the Sun are rocky planets. They consist of a metal core, a molten mantle and a solid crust. In addition, these planets are located relatively close to the Sun. The four rocky planets of our solar system are (in order from the Sun) Mercury, Venus, Earth and Mars. All of these planets have atmospheres except for Mercury.

An asteroid belt is located between the rocky and gas planets. The asteroid belt consists of thousands of small planets. Another asteroid belt, the so-called Kuiper zone, is located at the edge of our solar system, beyond Neptune. The dwarf planet Pluto is one of the millions of asteroids in Kuiper zone.

Outside the asteroid belt, large gas planets can be found orbiting the Sun. The four gas planets of our solar system are (in order from the Sun) Jupiter, Saturn, Uranus and Neptune. They all consist of a large gas core surrounded by a gas atmosphere. They are multiple times larger than Earth. Some of them have rings and numerous moons. Due to their distance from the Sun, they do not receive a lot of heat. As a result, the surface temperature of each gas planet has been calculated to be over a hundred degrees below zero.