The inner planets are those that are closest to the sun and are separated from the outer ones by the asteroid belt located between Mars and Jupiter, the inner planets are Mercury, Venus, Earth, and Mars. The outer planets are larger than the inner ones and are Jupiter, Saturn, Uranus, and Neptune.
Difference between outer and inner planets in tabular form
|The inner planets are rocky and solid surfaces.||Gaseous planets have a surface made up of gas and liquid.|
|The inner planets are small in size.||The outer planets are gigantic.|
|The inner planets have a slow rotation.||The outer planets have very fast rotation.|
|The inner planets have few satellites.||The outer planets have many satellites and moons.|
|The core of the inner planets is made of hot rock.||The core of the outer planets is made of ice.|
|The atmosphere of the inner planets is made up of helium and hydrogen or nitrogen and CO2.||The atmosphere of the outer planets is made up of helium and hydrogen.|
They are those that are farthest from the Sun and are located after the asteroid belt. These planets are known as giant planets since they are much larger than the inner planets.
Their atmospheres are very dense and because they are made up of gas and liquids, they are also known as gaseous planets.
They are those that have orbits farthest from the sun, their atmospheres are made up of helium and hydrogen, they also contain water, ammonia, and methane.
Examples of outer planets:
- Jupiter: It is the closest to the Sun of all the outer planets and it is the largest planet in the Solar System, it has so much matter that it surpasses all the other planets together. It has 17 satellites and rings that are invisible from Earth.
- Saturn: It is the second-largest planet in the entire Solar System, it has rings and more than 25 satellites, especially Titan, which has an atmosphere.
- Uranus: It has a faint blue surface due to the high concentration of methane. It is the only planet that rotates on its side, circling in its own orbit.
- Neptune: It is the planet furthest from the Sun. Its surface supports very strong winds and has 13 satellites, Triton is the largest of them. It also has rings, but they are hard to see.
Characteristics of the outer planets
These planets have certain common characteristics:
- They are found within the solar system.
- They do not have a solid surface.
- They are known as giant planets or Jovian planets, a name that comes from Jupiter.
- Most of the planets discovered outside our Solar System have a composition similar to that of the outer planets.
- They have high magnetic fields.
- They are also known as Jovian planets, a name that comes from Jupiter.
- Its rotation is very accelerated. Jupiter completes a revolution in less than 10 hours, Saturn does not reach 11 hours, Neptune rotates in 16 hours and Uranus does it in almost 17 hours and a quarter.
- In their orbits, we can find rings and satellites.
- The nuclei of Neptune and Uranus are composed of primeval ices under great pressure and temperature and in a liquid state.
The fifth outer planet, Pattie
According to a study carried out in 2016, the theory of a fifth gas giant planet was created, which would explain the anomalies caused in the objects of the Kuiper Belt. This planet is believed to have an orbit of 10,000 – 20,000 Earth years and similar in size to Earth or Neptune, its orbit is 20 times farther than Neptune’s.
The inner planets are those that lie before the asteroid belt. They are small planets formed by rocks and have an atmosphere, with the exception of Mercury.
These planets are also known as telluric or terrestrial. They are relatively dense and solid.
Examples of inner planets
- Mercury: It is the smallest planet and closest to the Sun. It has very high temperatures, so it does not have an atmosphere.
- Venus: It is located after Mercury, it is the hottest planet, with a surface covered by lava. It has a very dense atmosphere so it cannot be observed directly.
- Earth: It is the only planet with sufficient characteristics to host life. It has an atmosphere composed of nitrogen and oxygen, large amounts of water, and climatic variations.
- Mars: It hardly has an atmosphere, so it does not retain solar radiation and presents temperature variations of more than 100ºC. On Mars, there is the highest volcano in the Solar System, Olympus, with more than 25 kilometers high.
Characteristics of the inner planets
The inner planets share a number of characteristics:
- They are small.
- They have a high density, between 3 and 5 g / cm³.
- They are known as rocky because they are composed of silicates.
- Rotation on its axis is slow. Mars and Earth complete one revolution in 24 hours, Venus does it in 243 days, and Mercury in 58 days.
- Its core is made up of stone or rock.
- The only ones that have an atmosphere are Mars, Venus, and Earth.