Difference Between Inner Planets and Outer Planets

Inner Planets vs Outer Planets

The first eight planets of our solar system (Excluding the asteroid Pluto) are divided into inner planets and outer planets. Planets which are closest to the sun, the innermost planets, are categorized as inner planets, that are Mercury, Venus, Earth, and Mars. Inner planets are also known as terrestrial planets. The other four planets, the outermost planets, which are located far from the sun, are categorized as outer planets that include Jupiter, Saturn, Uranus and Neptune. “Jovian planets” is also used to refer the outer planets. The inner planets and outer planets are separated by a belt of asteroids.

Inner Planets

Inner planets are those which are much closer to the sun compared to the other. Inner planets posses some characteristics which are unique to them. These four planets are mainly made up of rocks, which contain minerals based on inorganic substances and their derivatives like soil and dust. All are compact solid bodies. These planets were formed earlier in the process of the birth of solar system. The inner planets consist of smallest planet of the solar system (Mercury), the densest planet of the solar system (Earth density of 5.52), the hottest planet of our solar system (Venus average temperature of 461.9 degree Celcius). These are mainly because of their rocky nature. They have no or few moons. They have no rings circling them.

Outer Planets

The outer planets, also known as gas giants, comprise of relatively large planets Jupiter, Saturn, Uranus, and Neptune. As discussed earlier they are situated far from the sun. These planets are mainly composed of gases like hydrogen, helium, methane, etc. Their density is relatively low but they are large in size. The biggest planet (Jupiter), Planet with large orbiting rings (Saturn),and planet with least density (Saturn) are in the outer planets. Outer planets often have number of satellites or moons. Outer planets have atmosphere which largely consist of lighter gases like helium, ammonia and hydrogen.

What is the difference between Inner Planets and Outer Planets?

- Though all inner planets and outer planets are in the same solar system, they have their own unique characteristics distinguishing them from one another.

- Inner planets are situated closer to the sun, while outer planets are far from the sun.

- Inner planets are small in size compared to the size of their counterparts.

- Outer planets are made up of gases, while inner planets are made up of solid rocks.

- Inner planets don’t have rings orbiting them, while outer planets have.

- Outer planets often have dozens of satellite or moons, while inner planets have little or no moons.

- Density of inner planets is much higher than that of outer planets.

- Outer planets are much cooler than the counterparts.