How are planets formed?
How were the planets of the Solar system formed? According to the leading theory known as the "protoplanet hypothesis", small space objects collided with each other, resulting in their fusion. Thus the large planets, including gas giants like Jupiter. But how, exactly, did this happen?! Let's understand.
Birth Of The Sun
According to this theory, about 4.6 billion years ago there was nothing but free gas and dust in the place of today's Solar system. These are known nebulae. One example is the Orion Nebula, which you can see in the night sky.
Then, as scientists say, something happened that caused a change in pressure in the center of the cloud. Perhaps the reason was the explosion of a supernova nearby or the change in the gravity of passing stars. Anyway, according to NASA, the cloud "crumbled", and the matter formed the disk.
The pressure in the center of the disk increased so much that hydrogen atoms, which previously freely moved in the cloud, began to contact each other. In the end, this interaction led to their merger and the formation of helium. This was the impetus for the formation of the Sun.
The sun was like a hungry baby and absorbed up to 99% of what was around it. However, it was still 1% of the matter. This is where the process of formation of planets began.
Time of chaos
At that time, the Solar system was, as they say, in disarray. But the planets formed relatively quickly. Gas and small particles of dust began to gather in clots. The young Sun pushed most of the gas to the back of the Solar system. Coming from him it was warm enough to evaporate any ice that was nearby. Over time, planets formed: rocky bodies are located closer to the Sun, and gas giants – further away.
However, about four billion years ago, as a result of an event called "late heavy bombardment" by scientists, small bodies hit large objects of the Solar system. According to the theory, the Earth was almost destroyed after an object commensurate with Mars crashed into it.
The reasons for this " bombing "are still a mystery, however, according to some scientists, this is due to the fact that gas giants, moving around small bodies on the periphery of the Solar system," disturbed " them. That would not have been the reason, in simple terms, the merger of protoplanets eventually led to the formation of planets.
The processes of formation of planets in the Solar system can not be considered fully completed. Between Mars and Jupiter lies a belt of asteroids that could possibly merge into planets if Jupiter's gravity were not so strong. In addition, there are many comets and asteroids, sometimes called "building blocks" of our Solar system.
What we have today
One of the most serious problems of this theory is the absence of records of the early history of the Solar system.
However, astronomers have found two ways to work around this problem. The first is simple observation. With powerful telescopes such as ALMA (Atacama Large Millimeter/submillimeter Array), astronomers can observe protoplanetary disks around young planets. We have numerous examples of stars around which planets are born.
The second method is modeling. To test their observations and hypotheses, astronomers create computer models. At the same time, testing is carried out several times under different conditions. If all the experiments show that the model is working, it probably corresponds to reality.