Birth of the Solar System

 

Since the beginning, the people of earth were curious about understanding the hidden facts of our solar system, that how our solar system came into being? How sun formed? Why first four planets are rocky and the last four are gas giants? Why do gas giants have rings? Why do planets and stars have spherical shapes? So, in this article, I will try to explain these questions simply.

It is confirmed by scientists that stars and planets are formed by Nebula. Nebula is basically a collection of dust and gas clouds present in space. The gas in the clouds is primarily hydrogen, with smaller amounts of helium and other elements like carbon, oxygen, nitrogen, and neon. The dust in the cloud consists of tiny solid particles, typically made of carbon, silicon, and other heavy elements. When the star is about to form something strange happens in the nebula. The movement of dust and gas clouds increases. Now the question arises how the movement initially increases? There are many reasons explained by scientists one of the reasons is according to scientists the movement of clouds initially speeds up because of the shock waves of supernova nearby. Supernova is a strong event in space that happens when a star after its life blasts. Now according to the law of conservation of angular momentum in order to conserve momentum when the radius of an object decreases then its speed increases and vice versa. Due to the increased motion of clouds in the nebula, it condenses, and dust and other particles present in it collide, these particles stick to each other forming clumps due to electrostatic force. These clumps don’t normally form on the earth because of gravitational force that overcomes that electrostatic force. The particles continue colliding forming an object called a protostar. When the protostar forms then its gravity also continues pulling particles toward it. When in the core of the protostar the temperature and pressure increase up to certain values then the nuclear fusion reaction start and the formation of the star starts. Now the size of the star depends upon the balance between 2 forces one is the pressure due to a fusion reaction that acts outward and one is gravity that acts inward. When this pressure is quite larger than gravity then the size of the star increase and when this pressure is not as much greater than due to gravity the size of the planet decreases. When both pressure and gravity are at equilibrium known as hydrostatic equilibrium then the size remain same. Same due to these clouds other planets are formed. Since these planets and stars are formed due to moving clouds so they also possess motion say rotatory.

Now let’s try to understand another question why planets and stars are spherical in shape? the answer is due to their gravity. Since their gravity is quite larger and gravity is a force that pulls everything towards its center including rocks and metals present in planets. So due to this, they acquire a spherical shape. It is the most stable shape having a low surface area to volume ratio. Try to understand with another example take a piece of paper and apply force on it in all directions you will see the flat paper will turn into a spherical shape because of the force you applied in all directions and in the case of shapes of planets and star this force is known as gravity. I hope you got the point. The reason asteroids have random shapes this is that their gravity is too low.

Now let’s try to understand another question why first four planets are rocky and the last four are gas giants? The temperature where the rocky planets are present was hotter as compared to outer region and at that temperature the heavy elements like iron, and nickel could condense into solid particles but the volatile gases couldn’t condense at this temperature so that’s why the planets present in this region have core made of the above-mentioned elements. While in the outer region, the temperature is quite much lower as compared to the inner region and at that temperature volatile gases like hydrogen, helium, and methane condenses into solid which then clumps together and formed the cores of gas giants. So, that’s the reason behind it.

Now let’s understand another question why gas giants have rings around them while rocky planets don’t have rings? The reason is simple the much stronger gravity of gas giants than rocky planets. Their gravity is much stronger and they trap the asteroids and rocks around it also the dust released by their moons. Among gas giants, the rings of Saturn are larger and visible only there are many reasons one of the reason is that rocks and dust present in its rings are good reflector that that present in other rings.

Now next question may arise why Pluto is not considered  planet? For finding the reason first understand the necessary conditions to be a planet. The conditions are below:

·      It must orbit around the Sun.

·       It must have sufficient mass to assume a nearly round shape.

·       It must have sufficient gravity causing the asteroids and other objects to move around it.

Pluto satisfies all the above conditions except the third one its gravity is much lower . That’s why Pluto is not considered planet.

           Next question may arise what is the Kuiper belt and asteroid belt? So the asteroid belt and Kuiper belt contains many asteroids and comet. Asteroid belt lie between the mars and Jupiter while Kuiper belt is present beyond the Neptune. Scientists say that these asteroids are leftover materials from the early Solar System that did not form into planets.

           So, in short our solar system consist of star Sun, eight planets, moons, asteroids, comets. Scientists say our solar system was formed nearly 4.6 billion years ago. I hope you understood the concepts well.