The history of the Solar System
Thanks to the research work into the Planets and the Stars, astronomers have been able to reconstruct the history of the Solar System and to foresee its future.
The formation of the Solar System
The Sun formed from a giant cloud of gas and interplanetary dust.
For not yet well-known reasons, probably after the perturbation produced by the explosion of a neighbour big star, the cloud collapsed under its weight and began to rotate.
Gradually it shaped into a disk, whose nucleus became increasingly thicker and hotter than the outer areas.
Later, in the centre of the disk, the mass became hot and dense enough to make the Sun shine: all that happened 4.6 billion years ago!
In that immense cloud of gases and dust some solid particles began to join together up to form the Planets, in less than 100 million years.
Close to the Sun, where the temperature was higher, some Planets fomed by the impact of rocky masses (Mercury, Venus, Earth and Mars).
In the outermost and coldest areas rocks and glaciers, melted together, formed the core of big Planets which, in their turn, attracted large amounts of gas coming from the former nebula: that happened to Jupiter, Saturn, Uranus and Neptune.
The future of the Solar System
The Solar system is bound to disappear.
This because, since the Sun has begun to burn, its energy has been supplied by the nuclear reactions converting the hydrogen into a heavier gas, helium.
Nevertheless, the hydrogen in the core of the solar nucleus will be over, less than 5 billion years from now.
At that time new phenomenon will be produced: the Sun will expand and become a red giant.
Earth will turn into a real furnace: its surface temperature will rise up to nearly 2000°C and the rocks will be converted in burning lava.
Yet, a long time before all that happens, oceans will dry up and any living being will have disappeared.
After the last tremors, the Sun will stop expanding; its mass will shrink giving rise to a small star the same size of Earth: a white dwarf, that will softly extinguish leaving the Solar System in the cold and darkness ...
