What is Solar System

The solar system is the set formed by the Sun and the eight planets with their respective satellites that rotate around it, they also accompany it in its displacement through the galaxy or the Milky Way dwarf planets, asteroids and innumerable comets, meteorites and interplanetary corpuscles . This system is located about 33,000 light years from the center of the Milky Way.

There are many hypotheses about the origin of the Solar System, the most current theories link its formation with that of the Sun, about 4.7 billion years ago. From an interstellar cloud of gas and dust that fragmented or collapsed, leading to the formation of a primordial solar nebula, and through the union of larger and larger particles the formation of current planets.

Until August 24, 2006 there were nine planets in the Solar System: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. On that date, the International Astronomical Union created a new kind of planet: the dwarf planets , where Pluto became part of them, along with Ceres and Eris ; and later, they have been joined by Haumea and Makemake .

Planets are bodies that move in elliptical orbits around the Sun (translation) and around themselves (rotation). In general, the distance from each planet to the Sun is twice the previous one. The planets, with the exception of Mercury and Venus, have satellites , smaller bodies that revolve around them. The best known satellite is that of the Earth, the Moon.

The planets closest to the Sun are called interior or telluric planets (Mercury, Venus, Earth and Mars) , they are small in size, high density, low speed of rotation and have few satellites; the distant planets are known as outer or giant planets (Jupiter, Saturn, Uranus and Neptune), they are large, of low density, fast rotating and have gaseous consistency and a greater number of satellites.

Jupiter is the largest planet, while Mercury is the smallest, Venus in mass and size has characteristics similar to Earth , and Mars, known as the red planet, is half the mass.

Apart from these main planets and their satellites, there are thousands of small bodies known as asteroids , which are located between the orbits of Mars and Jupiter, in a strip called the asteroid belt . Also we cannot forget comets (balls of ice and dust) and meteorites.

The solar system is the set of stars and celestial matter that gravitates in an orderly manner around the sun. There are several solar systems in the universe, but we usually refer to our solar system, located in the galaxy known as the Milky Way.

It is called the solar system because the central axis of rotation is determined by the sun. The sun attracts the group of planets, dust, matter, radiation and magnetic fields of the galaxy.

Among the components of our solar system are the following elements:

  • the central star sun;
  • the planets;
  • the dwarf planets;
  • satellites;
  • the minor bodies present in the interplanetary medium as well as the objects of the asteroid belt between Mars and Jupiter and the Kuiper belt (comets, meteoroids and asteroids);
  • the interplanetary medium (solar wind, dust, gas, radiation and magnetic fields).

Planets of the solar system

Illustration of the solar system with the planets surrounded by their main satellites and the dwarf planets. Above and in white, representation of the scale between the planets.

In our solar system there are eight planets, which trace elliptical orbits.

Following the order of proximity to the sun, the planets of the solar system are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Neptune and Uranus.

Mercury, Venus, Earth and Mars, closer to the earth, are considered terrestrial or rocky planets , because their surfaces are compact rocky.

Jupiter, Saturn, Uranus and Neptune are considered jovian or gaseous planets , named for their large size and gaseous nature, although some have solid centers.

Most of the planets have satellites . Among those discovered so far, the following can be mentioned:

  • Earth has a satellite called the Moon;
  • Mars has two satellites called Deimos and Phobos;
  • Jupiter has 79 satellites (for example, the moons Io, Europa, Ganymede, and Callisto);
  • Saturn has 82 satellites (for example, Titan);
  • Uranus has 27 satellites (eg Titania);
  • Neptune has 14 satellites (for example, Triton, Proteus, and Nereid).

You may also be interested in:

  • What is a planet?
  • Milky Way
  • Moon

You pose dwarfs

In addition to the eight planets, the solar system also has dwarf planets. Dwarf planets are so called because they are smaller in size than other planets and, due to their size, their gravity does not completely clear their orbit when they coexist with other bodies.

So far, five dwarf planets have been identified in our solar system: Ceres – located in the asteroid belt between Mars and Jupiter – and Pluto, Haumea, Makemake and Eris – located in the Kuiper belt.

Dwarf planets also have satellites , except for Ceres. The following may refer:

  • Pluto has five saltellites (Charon, Hydra, Nix, Cerberus, Styx);
  • Haumea has two salétites called Hi’iaka and Namaka;
  • Eris has a satellite called Dysnomia;
  • Makemake has a satellite called MK2.

Characteristics of the solar system

  • The solar system is only a small part of the universe.
  • The solar system has a heliosphereand a heliopause .
  • The heliosphere refers to the area of ​​the Milky Way that is subject to the sun’s magnetic field.
  • The heliopause is the limit of the heliosphere, in which the solar wind comes into contact with the interstellar medium, marking the boundary of the sun’s magnetic field.
  • Planets and asteroids rotate in elliptical orbits around the sun.
  • The sun is a star made of burning plasma, with a diameter of 696,000 kilometers.
  • Due to its dimensions, the sun gathers more than 99% of the matter of the solar system.
  • Most of the celestial bodies rotate in the so-called “plane of the ecliptic”.


by Abdullah Sam
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