We live on a planet within the solar system, which is itself surrounded by other planets. However, some people are unfamiliar with the definition of what a planet is . In astronomy and science, the definition is based on its characteristics and formation.
Therefore, in this article we are going to tell you in detail what a planet is, its characteristics, formation and much more.
what is a planet
A planet is a celestial body that orbits a star massive enough to be in hydrostatic equilibrium (between gravity and the energy produced by its core). This equilibrium allows it to maintain its spherical shape, control its orbit (preventing other objects from interfering with its path), and not emit its own light, but rather reflect the light of the stars it attracts.
Our Earth, like the other seven planets in the solar system, revolves around the sun. Both have characteristics that define the objects as "planets," but differ in their composition and location on Earth.
Planets can be composed of solid material and accumulated gas . The basic solid material is rock composed of silicates and iron. The gases are primarily hydrogen and helium. These planets also have different types of ice, consisting of methane, ammonia, carbon dioxide, and water. The composition of these celestial bodies also has implications for understanding how airplanes affect the environment.
The proportions and properties of these materials will vary depending on the type of planet. For example, rocky planets like Earth are made of rocky and metallic materials and, to a lesser extent, gases. In contrast, gaseous planets like Jupiter are made primarily of gas and ice.
Characteristics of the planets
The planets of the solar system are classified according to their composition and can be:
- rocky planet. Also known as "Earths" or "terrestrials", they are dense celestial bodies composed of rocky and metallic materials. The planets Mercury, Venus, Earth, and Mars are types of rocks.
- Gas planet. Also known as "Jovians", they are large objects that rotate rapidly compared to Earth. These planets have very thick atmospheres that generate strong magnetic fields, and they have many moons. Jupiter, Saturn, Uranus and Neptune are all gas planets.
The planets are also classified according to their position in the distance from the sun and can be:
- inner planet. They are the closest planets to the sun, before the asteroid belt. They are Mercury, Venus, Earth and Mars.
- Outer planets. They are the most distant planets from the sun, second only to the asteroid belt. They are: Jupiter, Saturn, Uranus and Neptune.
Since its discovery in 1930, Pluto was considered a planet until 2006, when, after intense international debate, it was reclassified as a "dwarf planet" of the solar system because it did not meet the criteria for planetary status. One of the characteristics of a planet is that it lacks orbital dominance (its orbit is not clear of other objects; it has five moons with the same type of orbit). Pluto is a dwarf planet, a rocky exoplanet, because it is the celestial body farthest from the Sun. In addition to Pluto, other dwarf planets have been recognized, such as Ceres, Hemea, Makemake, and Eris.
Planets of the solar system
There are eight planets in our solar system, in order from closest to the sun to furthest:
- Mercury. It is the smallest planet in the solar system, with a rocky body similar to Earth, and its core occupies almost half of the Earth (generating a strong magnetic field). It has no natural satellites.
- Venus. It is the third planet in terms of size (from smallest to largest), has a diameter similar to Earth and has no natural satellites.
- EarthIt is the fourth planet after Venus and has only one natural satellite: the Moon. It is the densest planet in the solar system and the only one with water on its surface. You can learn more about its impact on the environment at how the airplane affects the environment.
- Mars. It is the second smallest planet and is also known as the "red planet" because its surface is red due to iron oxide. It has two small natural satellites: Phobos and Deimos.
- Jupiter. It is the largest planet in the solar system. It is gaseous, composed mainly of hydrogen and helium, and has sixty-nine natural satellites.
- Saturn. It is the second largest planet (after Jupiter) and the only planet in the solar system that has a planetary ring (a ring of dust and other small particles orbiting it). It has 61 detected satellites, but estimates put the total at around 200.
- Uranium. It is the third largest planet and has the coldest atmosphere in the solar system. Its interior is composed mainly of ice and rock, and there are twenty-seven natural satellites detected.
- Neptune. It is the fourth largest planet and has a similar composition to Uranus, with a lot of ice and rock in its interior. Its surface is blue due to the presence of methane gas. It detected fourteen satellites.
Natural satellite
A natural satellite is a celestial body that orbits another star (usually a planet) and accompanies it in its orbit around the star. It is characterized by being solid, smaller than the star it orbits, and can be bright or opaque. Some planets can have several natural satellites, which are held together by mutual gravity.
Our planet's natural satellite is the Moon, which is about a quarter the diameter of Earth and is the fifth largest moon in the solar system. Its orbital distance is 30 times the diameter of Earth. The Moon takes 27 days to orbit Earth and rotate on its axis, so the same lunar surface is always visible from Earth.
Natural satellites are different from artificial satellites. The latter is made by humans, and also remains in orbit around the space object, where it remains in orbit as space debris once its useful life ends, or disintegrates if it passes through the atmosphere on its return.
I hope that with this information you can learn more about what a planet is, its characteristics and types of planets that exist.
