What is the solar system?

We explain what the solar system is and what its characteristics are. How it is formed and what are the planets of the solar system.

1. What is the solar system?

The Solar System is the planetary context where our planet Earth is located : a circuit where eight planets constantly orbit a single star , which is the Sun.

Of course, ours is not the only planetary system that exists. There are systems of dynamic forces around the gravity of one or more stars throughout the galaxy and the universe , so it is relatively safe to assume that there are incalculable similar systems.

Our Solar System is part of the Local Interstellar Cloud , within the Local Bubble of the Orion arm , located about 28,000 light years from the bright center of our galaxy, the Milky Way. It is estimated that it was formed 4568 million years ago, as a result of the collapse of a molecular cloud in, giving rise to a circumstellar or protoplanetary disk, that is, a messy set of matter surrounding the Sun in the form of rings. From there the different planets and astronomical objects of our space neighborhood would have been constituted.

The objects of the solar system and other planetary systems are maintained in orbit elliptically around the astro larger and therefore more serious system. In our case, of course, it is the Sun, a G-type star of 1,392,000 kilometers in total diameter, which contains 99.86% of the total mass of the System.

2. How is the solar system formed?

As has been said, at the very center of the Solar System is the Sun , a yellow dwarf star of luminosity V, and the only star that emits its own light in the whole. Around it orbit eight planets of different sizes and at different distances, tracing elliptical paths.

In the same way there is an abundant field of asteroids, in a belt that is after Mars , and a much larger one after Neptune. In addition, there are asteroids in the rings that surround the great outer planets such as Saturn and Uranus.

Natural satellites, such as our Moon, or the moons of Mars: Deimos and Phobos, which are abundant on the outer planets, must be mentioned: Jupiter and Saturn have 63 and 61 respectively, while Neptune and Uranus are 27 and 13.

Finally, there is a series of trans-Neptunian objects, the furthest from the Sun of the system, whose little impact of sunlight makes it difficult to study, but which would be hypothetically three:

• The Kuiper Belt , a tangle of celestial bodies that orbit the Sun faraway, and among which the short-period comets that visit us from time to time could be born . Pluto and its Charon satellite are considered the largest objects in this group.
• The Scattered Disc , a region of space overlapping with the Kuiper Belt and extending to an unknown distance, away from the Sun. There would be an uncertain number of astronomical objects, estimated to be around 90.
• The Oort Cloud , a spherical cloud of celestial bodies, located almost a light year from the Sun, a hundred times farther than the Kuiper Belt. It is assumed that there would be between one and one hundred billion objects, totaling a total mass five times higher than the land.

3. Planets of the solar system

There are eight main planets in the solar system, divided into two groups:

• Inner planets , the closest to the sun and the smallest: Mercury, Venus, Earth and Mars. They are also called terrestrial or telluric planets, since they have a solid, concrete surface, around which there is an atmosphere (except in the case of Mercury).
• Outer planets , which are after the asteroid belt in the middle of the planetary system, gigantic and basically gaseous: Jupiter, Saturn, Neptune and Uranus. The last two are known as the frozen giants.

There is also a set of dwarf planets, including Pluto since 2006 : Ceres, Makemake, Eris and Haumea. They have enough mass to acquire a spherical shape, but not to attract or repel objects around, so they are considered at an intermediate level between planets and asteroids.

Recent studies indicate that there could be a ninth planet, provisionally called Phattie, but nothing has been confirmed yet.