About 4.5 billion years ago our solar system was formed. Although scientists are not sure how the process went, observing young star systems has allowed them to develop three theories of what could have happened millions of years ago. However, scientists believe that the solar system developed after a gravitational collapse of a giant molecular cloud.
Rise of the Sun
According to the scientific and astronomical community, a massive concentration of interstellar gas and dust created a molecular cloud that formed the birthplace of the Sun. Low temperatures caused the gas to become increasingly dense. Thus, the densest parts of the cloud began to collapse under their own gravity, forming a large number of young stellar objects (protostars).
Gravity gathered a lot of material in the center of the cloud and its temperature and pressure were very extreme, which is why it continued to collapse. In this way, a star was created and an accretion disk from which the planets were formed. The cloud was so dense and hot that it triggered a nuclear fusion reaction. Thus was born the Sun and probably our entire solar system.
After the Sun formed, a huge disk of material surrounded it for about 100 million years. Although it may seem like a long time, in astronomical terms it is not that long. Thus, as the Sun warmed up, the gas evaporated, giving the planets and moons very little time to collect said gas.
Three training models
Scientists have established three different models to explain how the solar system and the planets may have formed. The first model (and most accepted by the scientific community) is the accretion of the nucleus. This solves the formation of the rocky terrestrial planets, but does not explain exactly the rise of the giant planets.
The second model is that of the accumulation of pebbles, which could explain why planets formed quickly from smaller materials. The third, for its part, is the disk instability method. Unlike the first model, this one does clarify the creation of the giant planets.
Central accretion model
It is the model most endorsed by the scientific community. About 4.6 billion years ago, the solar system was a cloud of dust and gas known as a solar nebula. Gravity collapsed the material on itself and it began to rotate, forming the Sun at the center of the nebula. With the birth of the Sun, the remaining material began to clump together.
The smaller particles came together due to the force of gravity, becoming larger particles. The solar wind expelled the lighter elements (such as helium and hydrogen) from the closest regions, leaving only heavy and rocky materials.
