Sun system

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The solar system is made up of the Earth, planets and asteroids. All of them revolving around the Sun.

On the cover imagen you can see an artist’s conception of the solar System. Credit: Author: Dr.Maggie Aderin-Pocok, web “”.

The existence of the solar system

The existence of the solar system as a result of the gravitational interaction between particles of matter is truly amazing.

Due to the gravitational force, the Sun carries with it planets, asteroids and particles of cosmic dust that rotate around it, forming what we call the Solar System.

The solar system
Artist’s conception of the dust and gas surrounding a newly formed planetary system.  Credit: NASA

Since the time of Isaac Newton it has been known that two particles of matter attract each other with a very weak force called the gravitational interaction.

This interaction, also called the force of gravity, has the curious characteristic that its radius of action extends to infinity.

The forcé of gravity interact in such a way that, if the masses are large, this mutual attraction between two material bodies can be very strong, even though they are billions of kilometers apart from each other.

This is what happens, for example, between the Sun and the distant Pluto.

The Sun, even though it is a medium-sized star, has a massive mass of millions and millions of tons (roughly 2 followed by 27 zeros, 332,950 times the mass of Earth).

How did the solar system form

The current prevailing hypothesis in the scientific world is that the solar system was formed 4.6 billion years ago due to the forces of gravitational attraction on a giant molecular cloud (several light years long).

This cloud would have been composed of 98% hydrogen and helium that gave rise to the nuclei of very large bodies that over time dispersed.

The solar system
About 4.5 billion years ago, our sun and solar system formed in just 200,000 years  Credit: web “”

How did the solar system form? One of the generally accepted theories postulates that when the nebula collapsed, the forces of gravity and the laws of mechanics gave this matter an increasingly rapid rotating movement.

Before long, the material in the nebula condensed and the inner atoms began to collide with increasing frequency, releasing energy in the form of heat, especially in the center, where there was a greater accumulation of mass.

Scientists estimate that the solar system is at least 4,600 million years old.

The oldest rocks on Earth are approximately 4,400 million years old.

The oldest meteorites found on Earth (such as the Devil’s Canyon meteorite in the USA) are estimated to be 4,600 million years old.

How the sun was formed

Rotation, forces associated with gravity, gas pressure, magnetic fields, and rotation caused the nebula to begin to flatten out into a huge disk with a hot, dense star at its center, as seen in the artistic representation of the figure above.

The disk spread out enormous distances and the matter that was moving away from the center cooled.

Sun parts
Various parts and areas of the sun   Credit: Microsoft illustration

At the center of that huge disk, the temperature and pressure in the Sun’s core became so great that its hydrogen began to melt, creating an internal source of energy that counteracted the force of gravitational contraction until hydrostatic equilibrium was reached. .

After 100 million years since the collapse of the gas nebula, the Sun had become a new star.

The theory is now accepted that the planets began as grains of dust orbiting the Sun.

The force of gravity caused them to collide and form larger bodies on the outside of that huge disk.

This process may have lasted about 100 million years.

Orbits The solar system
All the planets, asteroids, meteoroids, and comets in the solar system orbit the sun.  Credit: web “”

Solid bodies formed near the Sun which are what we call rocky planets: Mercury, Venus, Earth and Mars.

The astronomical record of Jupiter has characteristics that make it very different from an ordinary planet like Earth.

Planets of The solar system
Eight planets of the solar system Credit: Wikipedia

Beyond the asteroid belt and beyond the freezing line, large planets were formed that accumulated hydrogen and helium gases that could remain solid and that constitute a high percentage of their mass: 97% in the case of Jupiter and 90%. in that of Saturn. Jupiter and Saturn are the gas giants.

Uranus and Neptune are younger planets that reached critical size to collapse much later and captured much less material.

They are known as ice giants because their cores are believed to be made primarily of hydrogen in the form of ice.

Icy hydrogen and helium currently make up about 33% of its total masses.

Over thousands and millions of years, the gravitational forces of these gigantic masses of matter are attracting the closest bodies and are cleaning the surroundings and collecting this space debris.

This is one of the characteristics that have been considered to disqualify Pluto as a planet, since its small size has not allowed it to clean the neighborhood.

Around Pluto, in a region 30 to 100 times the distance that separates the Earth from the Sun, more than 800 small frozen objects have been discovered.

Kuiper belt
Kuiper Belt.  Credit: web “”

Astronomers have long considered Pluto and Charon to be the largest objects in this group, which is called the Kuiper Belt. The bodies in this Belt are also called “trans-Neptunian objects“: they are further from the Sun than Neptune.

On June 4, 2002, a body larger than the moon Charon and almost half the dwarf planet Pluto was discovered.

It was called Quaoar and it became the second largest body in the Kuiper belt after Pluto.

But on November 13, 2003, the discovery of a large body much further away than Pluto was announced, which they named Sedna and that dethroned Quaoar from the position of the second largest trans-Neptunian object.

Moon origin
Artist’s depiction of a collision between Earth and a Mars-sized object likely formed the Moon  Credit: web “”

With respect to the origin of the Moon, Earth’s satellite, a fairly established theory postulates that about 4,000 million years ago a primitive planet, close to Earth and the size of Mars, impacted with the Earth and produced the detachment of a part of both of them.

At the same time, this gigantic impact could have altered the Earth’s axis of rotation to its current 23.5º with respect to its orbital plane.