A brief note on Planets

Our vast solar system comprises a lot of planets, asteroids, meteors and so much more. In this section we will be focusing on planets in detail. A planet can be described as a celestial body that is in orbit around the Sun, has adequate mass for having an approximately rounded shape and has ‘cleared the neighbourhood’ around its orbit. The eight planets in the order from their distance to the Sun are as follows – Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Pluto is now designated as a dwarf planet. As we move forward, we shall study the different ways through which planets can be classified. 

Classification of Planets

A commonly used way for classifying planets is dividing them into inner planets and outer planets. The inner planets include Venus, Mars, Mercury and Earth. These are rocky planets. The outer planets include Jupiter, Saturn, Uranus and Neptune. Jupiter and Saturn are known as gas giants, whereas Uranus and Neptune are known as ice giants. After Neptune, another classification of planets includes dwarf planets. Pluto is said to be a dwarf planet. 

Gas Giant Planets

A large planet that is mainly composed of Hydrogen or/and Helium can be called a gas giant. Planets such as Saturn and Jupiter are the ones which instead of having hard surfaces rather have gases above a solid core. Here is a brief description of the four gas giants in the solar system: –

1. Jupiter – Within the solar system, Jupiter is known as the largest planet. It is mainly made up of helium and hydrogen. It is said that even the ancients were familiar with Jupiter. 
2. Saturn – The notable characteristic of Saturn are its rings. The atmosphere of Saturn is similar to that of Jupiter. It is also made up of helium and hydrogen. 
3. Uranus – The first gas giant which was discovered through the means of a telescope is Uranus. William Herschel discovered Uranus in the year 1781. 
4. Neptune – The atmosphere of Neptune is also made up of methane, hydrogen and helium like Uranus only. In the year 1846 only, Uranus was discovered. 

Exoplanet Classification Schemes

As of now, the planets have been categorised into different ways such as gas giant, super-Earth, terrestrial and Neptunian. Exoplanets can be described as those planets which are beyond the solar system. These planets come in a diversity of sizes. These planets can be locked in deep freeze or be hot enough for boiling. 

It was in the 1990s that the exoplanets were first discovered. There are various types of exoplanets and these are discussed below: – 

1. Gas Giants – Gas giants are those plants that orbit very near to their starts and therefore can have an extremely high temperature. Saturn and Jupiter can be called Gas Giants. 
2. Neptunian Planets – In the solar system, the planets which are somewhat similar to Uranus or Neptune in terms of size are called Neptunian Planets. 
3. Super-Earths – Super-Earths can be explained as those which are mainly terrestrial planets. The atmosphere might or might not be there on these planets. 
4. Terrestrial Planets – Those planets which are similar to Earth in terms of their size or can be smaller than Earth in size can be called terrestrial planets. These planets are composed of silicate, carbon, water or rock. 

Thus, this helps to understand the various types of exoplanets. 

Conclusion

Thus, as observed from above, the topics pertaining to the solar system and the classification of planets have been comprehensively covered. From understanding what a planet is to classifying the types of exoplanets and learning about the gas giant planets, various topics have been covered above. The gas giant planets which are composed of Hydrogen or/and Helium and are large in size are also discussed in detail. Exoplanets can be classified as per their size, their exterior appearance as well as their interior appearance based on their composition. Gas giants, Neptunian Planets, Super-Earths and Terrestrial Planets have been mentioned along with their description. Thus, it can be concluded that the solar system, the planets of the solar system and their classification are now clearly understood.