Do you know where our planet is? Yes, this planet is in a system called the solar system . Well, the solar system itself is one of the star systems within the scope of the Milky Way galaxy.
So, what is meant by this solar system. The solar system is a unit that consists of the sun as its center, and is surrounded by its members consisting of planets, moons, meteors, comets, and other members that keep moving.
In this solar system, only the sun can emit its own light. While members of other solar systems can only reflect light. After knowing what the solar system is, then did you know about the process of forming the solar system?
The discussion of how the Solar System was formed has been widely explained in theories of the formation of the solar system. In the theory of the occurrence of the solar system, explained about how the sun, planets, and satellites are able to work regularly in this system.
These theories are indeed not absolutely true. However, this theory was put forward by experts through great effort with various studies, observations and experiments, until finally found the theory of the formation of the solar system on a logical basis.
There are several theories of the formation of the solar system that are widely known and recognized. Some of these are the nebulae theory, the plantesimal theory, the tidal theory, the lyttleton theory or twin stars, the dust cloud theory, and the culper hypothesis.
1. Nebula Theory
In the Nebula theory, it was revealed that at first the solar system was formed from a nebula or a very wide thin mist. The glowing nebula or gas mass of this giant rotates slowly which then gradually cools, shrinks and approaches a spherical shape.
Rotations that occur are getting tighter and faster, causing the center of the mass to balloon. As a result, the circle of material is thrown out.
This circle then cools, shrinks, until finally it becomes planet-planet. Planets that are formed still orbit around the nucleus of mass. While another circle was thrown again from the center of mass to become the entire planet that we know today, including the earth.
The center of mass is the sun. Next, the planets that also threw their mass out of space so that it turned into a satellite like the moon that is owned by the earth.
The Nebula theory is known to have first appeared in the XVIII century which was preceded by the opinion of a German philosopher named Immanuel Kant. Kant’s opinion about the solar system formed from the nebula was later strengthened by Marquis de Laplace (Piere Simon), who was a French astronomer.
The theory expressed by Laplace is more of an explanation of Kant’s opinion. Even though Laplace did not know the contribution of Kant’s thought in his theory. Because it comes from the thinking of these two experts, the Nebula theory is also often referred to as the Kant-Laplace Theory.
2. Planetesimal Theory
What is meant by planetesimal is a small solid object that moves around a gaseous nucleus. Planetesimal theory states that one day a star crosses space quickly and is very close to the sun.
The passing star seems to have such a great attraction that it causes tides in the solar hot gas. Therefore, there is a mass of gas from the sun that is thrown out and begins to orbit the sun.
However, because of the attraction the sun still has, the gas mass is held up and moves around the sun. The mass of this gas gradually cools and forms into a liquid which then solidifies. That mass is what we know today as planets, including our earth.
This Planetesimal theory first appeared around 1900. This theory was first put forward by an astronomer named Forest Ray Moulton and a geologist named TC Chamberlain from the University of Chicago.
The planetesimal theory is based on the observation that some stars in the sky seem to never stop moving. One time, the star that kept moving passed very close to the Sun.
Then because of the gravitational force, then there was an attractive force between the sun and the passing star. Tides occur that result in the formation of planets. This formed planet that might follow the stars that passed earlier.
Also see: Understanding Hydrology, Hydrological Cycle and Types of Hydrological Cycles
3. The Tidal Theory
Tidal theory or tidal theory is also sometimes referred to as the theory of collision ideas. In the tidal theory or the theory of collision ideas, it is stated that planets were originally formed directly by the original gas of the sun attracted by stars that crossed very close and were almost in contact with the sun.
This theory is indeed almost the same as the planetesimal theory. Only difference, in this tidal theory, planets are not formed by planetesimals. This theory states that when a star is very close to the sun, there is a gravitational pull that sucks a long, cigar-shaped gas filament.
This filament enlarges in the middle and shrinks at both ends. From this filament, then formed a planet. This opinion was first coined by Sir James Jeans and Sir Harold Jeffreys from England in 1918.
Jeans and Jeffreys assume that the birth of the Solar System is a rare event. Because, this event occurs when the sun is almost tangent to a star. The event that caused the sun’s tongue to be shaped like a cigar is also a logical explanation of the size of the planets that are different from each other.
4. Lyttleton Theory or Twin Star Theory
Lyttleton’s theory or also often referred to as twin star theory suggests that the sun was originally a twin star surrounding a gravitational field. But, there is a star that hit one of the twin stars and maybe destroy it.
The destroyed star then turns into a mass of gas that is spinning. Because it keeps turning, the mass of the gas turns cold and forms planets. While one other star that survived became the center of the solar system that we know as the sun.
The sun is able to hold the planet formed because it has the force of gravity. Therefore, planets can circulate according to their path around the sun. Because the assumption of the formation of the solar system is due to a collision, then that is why this theory is also known as the theory of collision ideas.
Lyttleton’s theory was coined by RA Lyttleton who was an astronomer. He made modifications to the theory of collisions that had previously existed. However, the theory expressed by Lyttleton is considered to have a better explanation of the origin of the Solar System based on the collision theory.
5. Dust Cloud Theory
Dust Cloud Theory reveals that the Solar System candidate was originally a very large cloud. This cloud consists of cosmic dust and gas which is thought to be shaped like a plate.
However, there is an irregularity in the cloud that causes rotation so that the gas and dust that rotates together. While this dust and gas continues to spin, the cloud disappears.
Then, hard dust particles collide with each other, cling to and turn into planets. Then the various gases in the midst of clouds develop and become the sun.
The Dust Cloud Theory was coined by Fred L. Whippel who was an astronomer from the United States . If traced from the process, this theory seems to be a development of the Nebula theory.
Besides what Fred L. Whippel revealed, there was also an English astronomer named Fred Hoyle and a Swedish astronomer named Hannes Alven who expressed a theory similar to the Dust Cloud theory.
They argue that in the beginning the Sun rotates rapidly with a disk of gas around it. When referring to the research of the modern era, the Sun is said to revolve about once in 27 days.
While the latest calculations also show that the primitive Sun rotates faster so that it is possible to throw materials that then form planets. This is what supports this dust cloud theory.
6. Kuiper’s Hypothesis
In the Kuiper Hypothesis, it was stated that the universe originally consisted of star formations. Then, there are two centers that solidify and develop in an interstellar cloud of hydrogen gas.
One center is bigger than the other center. This one larger center then solidifies and becomes the single star we know as the sun.
This hypothesis was put forward by Gerard P Kuiper (1905 – 1973). Because it is still a hypothesis and has not been considered a theory that has a strong foundation, Kuiper’s opinion is quite rarely used.