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.
There are eight main planets in the solar system.
The Solar System is the planetary context in which our planet Earth is located: a circuit in which eight planets constantly orbit a single star, which is the Sun.
Of course, ours isn’t 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 incalculable similar systems exist.
Our Solar System is part of the Local Interstellar Cloud within the Local Bubble of Orion’s arm, located about 28,000 light years from the bright center of our galaxy, the Milky Way.
It is calculated that it was formed 4568 million years ago, as a consequence of the collapse of a molecular cloud in, giving rise to a circumstellar Disc or protoplanetary, ie a disordered 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.
Objects in the Solar System, as in other planetary systems, are held in an elliptical orbit around the largest and, therefore, most serious star in the system.
In our case, of course, it is the Sun, a G-type star with a total diameter of 1,392,000 kilometres, which contains 99.86% of the total mass of the System.
How is the solar system formed?
As has been said, at the very centre 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. Eight planets of different sizes and distances orbit around them, tracing elliptical trajectories as they go.
There is also an abundant field of asteroids, in a belt after Mars, and a much larger belt after Neptune. In addition, there are asteroids in the rings surrounding the great outer planets such as Saturn and Uranus.
Mention should also be made of natural satellites, such as our Moon, or the moons of Mars: Deimos and Phobos, which are abundant on the outer planets: Jupiter and Saturn have 63 and 61 respectively, while Neptune and Uranus have 27 and 13.
Finally, there is a series of Transeptunian objects, the furthest from the Sun of the system, whose little impact of sunlight makes it difficult to study, but which would hypothetically be three:
- Kuiper’s Belt, a tangle of celestial bodies orbiting far away from the Sun, from which the short period comets that visit us from time to time might be born. Pluto and its satellite Charon are considered the largest objects of this group.
- The Disperse Disk, a region of space overlaid with the Kuiper Belt and extending to an unknown distance away from the Sun. There would be an uncertain number of astronomical objects, estimated at around 90.
- The Oort Cloud, a spherical cloud of celestial bodies, located almost a year’s light 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 there, which add up to a total mass five times greater than that of the Earth.
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, because 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 spherical form, 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 may be a ninth planet, provisionally called Phattie, but nothing has been confirmed yet.