The Birth Of The Solar System

 

 

The origin of the Sun and of the Solar System is connected to the condensation of a primordial cloud of gas and dust as those often seen in our galaxy. It is probable that an external event triggered the collapse of the cloud, since its parts were in equilibrium. Scientists have put forward the hypothesis that it could have been the explosion of a nearby supernova, i.e. a star with a great mass that has an explosive death expelling all its atmosphere into space. The silent shock wave must have given the cloud the initial push: so the death of a star can bring about the birth of another star.

Once the collapse has been triggered off it proceeds on its own: as the distance between the matter that composes the cloud diminishes, a stronger gravitational force is generated which tends to pull the mass together. The free-falling matter does not fall in a straight line towards the centre, but rotates around it in tighter and tighter spirals. Both the rotation of the Sun and the planets around their axis, and the revolution of the planets and other bodies around the Sun are a consequence of this initial vortex.
As the collapse proceeded, most of the cloud matter concentrated in the central regions reaching the density and temperature required to form a star, a body capable of producing and emitting energy on its own. On the edge of the cloud, instead, the remaining matter continued to rotate around the centre, thinned into the shape of a disc, and formed the planets from the dust grains present, through collisions and successive aggregations. Still today, the main bodies of the Solar System rotate around our star on the same plane, which is called the ecliptic. Scientists believe that the asteroids, frozen bodies and dust that are present in our planetary system represent the oldest residues of its formation; in other words, they are the result of primordial aggregations that were not able to evolve into planets. The fact that their orbits are more inclined respect to the ecliptic plane testifies that these bodies were excluded from the main formation mechanism that took place along the rotation disc.
Today the Sun has been burning for 5 billion years and will continue to do so for another 5 billion more. Once all the hydrogen, its main fuel, is consumed, it will expand into a red giant, engulfing the entire Solar System up to Mars’ orbit (the Earth is included!). Subsequently, it will shed its outer layers in a gust of gas and it will enter the final phase of its life cycle changing into a white dwarf, a small dimly luminous star destined to get cold and to slowly die off.

.More Details