Gas Giants Caused a Stir

In a belt at the centre of the Solar System, you will find 750,000 asteroids. They could have united into a planet, but two gas giants disturbed them.

Diameters of up to 1,000 km. Those are the dimensions of the 750,000 asteroids which are orbiting in the void between the four rocky planets in the inner Solar system and the four gas giants in the outer Solar System. The asteroids are probably what remained after the formation of the Sun and the planets. But it is still difficult for astronomers to explain why the asteroids are located there instead of uniting into a planet.

Scientists from NASA, Observatoire de la Côte d’Azur in France, have proposed the Grand Tack model of the formation of the Solar System. According to the model, the four outermost planets – Jupiter, Saturn, Uranus, and Neptune – formed after the birth of the Sun, whereas the inner planets had not yet formed, making up a disc of raw materials.

By means of sophisticated computer simulations, scientists have calculated that Jupiter and Saturn could have moved towards the Sun. Today, Jupiter is five times as far away from the Sun as Earth, but in the Solar System’s early childhood, the planet travelled to a distance of about 1.5 times that of Earth. In a zigzag manoeuvre, Jupiter and Saturn turned around, moving outwards again. En route, the gas giants pushed the asteroids to the area, in which the Asteroid Belt is located today.