The Solar System, recognized by astrologers as “Our System”, is composed of planets and asteroids that revolve around the only star that gives the system its name, the Sun .

All the elements that compose it revolve directly or indirectly around the Sun because of the tensions created by the mass of each celestial body. There are many similar systems in the Universe, but this is the one that interests us since we depend on it to survive.

In this article we will see which are the planets of the Solar System .

How is the Solar System formed?

It should be noted that the Solar System was formed some 4.6 billion years ago as a result of the gravitational collapse of a giant molecular cloud . This phenomenon led to the formation of billions of other stars which, according to the experts, are still unknown.

Among the main elements that give shape and life to the Solar System, we also find minor planets, dust, interstellar gas, satellites and asteroids. All of these belong to the famous Milky Way, which in turn is made up of hundreds of billions of stars. Our Solar System, then, is located in one of those arms of the Vía, called Orion.

Main characteristics

The bodies that give shape and life to the Solar System are the Sun, which accounts for 99% of the total mass of the system and has a diameter of 1,500,000 kilometres , and the planets, divided into two types called inner and outer. It should be noted that the outer planets are surrounded by a ring. The dwarf planets, which are in another category of the above mentioned, include celestial bodies such as Pluto or Eris.

Satellites are another important element , as they are larger bodies that orbit large planets such as Jupiter or Planet Earth, whose only satellite is the Moon.

On the other hand, we find its little brothers, the smaller bodies, which are concentrated in the asteroid belt between Mars and Jupiter. Asteroids, icy objects, liquids, gases, comets, cosmic dust and meteoroids represent the rest of the elements for the Solar System to take shape.

The three categories

To better understand this system, scientific astronomers have decided to establish a classification of three categories of the Solar System that explain its formation.

Category one

In this category are the 8 planets that form the Solar System. The terrestrial planets are Earth, Mars, Venus and Mercury. The outer or giant ones (already mentioned in the previous point) are Neptune, Uranus, Jupiter and Saturn. Here all the planets have satellites that orbit around them.

Category two

Here are the so-called dwarf planets. This is a celestial body orbiting the Sun, spherical in shape but without enough mass to clear the vicinity of its orbit . Here is the reason for its nomenclature. The planets that form this second category are Ceres, Eris, Haumea, Pluto and Eris.

Third category

In this category reside the so-called “minor bodies of the Solar System”, which are all the remaining objects that orbit the Sun : they are the asteroids (composed of amorphous forms), objects of the Kuiper belt, the meteoroids and the icy comets.

The Planets of the Solar System

As we have described in the previous points, the planets of the Solar System are the most important part of all its complex composition. We will now go into each of them in more detail.

1. Mercury

We start with this planet as it is the closest to the Sun, apart from being the smallest of its counterparts. It has a similarity to the Earth, since its composition is 70% of metallic elements and the remaining 30% corresponds to silicates . Furthermore, as with the moon, Mercury has a large number of meteorite impacts.

2. Venus

Venus is the second most distant from the Sun . Among the planets of the Solar System, Venus is often called the “brother planet of the Earth” because of its similarity in size and mass and its earthy and rocky composition.

3. Earth

Planet Earth, our planet, is the largest of the so-called rocky planets. It was formed about 4600 million years ago and its name comes from the Latin “Terra”, a Greek deity that corresponds to femininity and fertility. 71% of its composition corresponds to the hydrosphere (water), a differential fact that has allowed the existence and persistence of human life. No other planet in the Solar System contains such a level of liquid.

4. Mars

Mars is the second smallest planet in the solar system, after Mercury. For a long time it has been commonly known as the “red planet” , the result of the reddish colour it acquires from the iron oxide on most of its surface. Its size is almost half that of the Earth and its gravity 40% less, which makes it practically uninhabitable according to the latest research by NASA.

5. Jupiter

The Planet of the Solar System named after the God Zeus of Greek mythology (Jupiter in Roman mythology) is, preceded by the Sun, the planet with the largest celestial body. It is 1300 times bigger than the Earth. As a massive gaseous body, its composition is basically made of hydrogen and ice. As a curious fact, is considered the oldest planet in the Solar System , preceding the Sun even.

6. Saturn

This planet of the Solar System is famous for its imposing brightness from its rings that surround the planet. Going back to Galileo, he first sighted it in 1610. Practically the entire planet (96%) is made up of hydrogen and the remaining 3% is ice.

7. Uranus

This planet is considered the first to be discovered by a telescope. Its composition is very similar to that of its brothers Saturn and Jupiter, since it is formed by helium and hydrogen, as well as water, ammonia and methane but in greater quantities. A peculiarity of this planet of the Solar System is its atmosphere , with the lowest temperatures of the whole System, reaching the minimum of -224 degrees Celsius.

8. Neptune

Neptune was discovered about two centuries ago by Urbain Le Verrier, John Couch and Johann Galle, back in 1847. However, some historians and astronomers maintain that the famous Galileo Galilei observed this planet as early as 1612 , a fact that has not yet been confirmed. The planet Neptune is composed of molten rock, water, methane, hydrogen, ice and liquid ammonia.

Bibliographic references:

  • Giancoli, C. D. (2007). “Circular motion and gravitation”. In Pearson Education. Physics: Principles with applications (sixth edition). Mexico D.F. pp. 125-126.
  • Sukyoung Yi; Pierre Demarque; Yong-Cheol Kim; Young-Wook Lee; Chang H. Ree; Thibault Lejeune; Sydney Barnes (2001). Toward Better Age Estimates for Stellar Populations: The Y2 Isochrones for Solar Mixture. Astrophysical Journal Supplement 136: pp. 417-437.