Terrestrial Planets

A terrestrial planet often called a telluric planet or a rocky planet is made up mostly of silicate rocks or metals. The four innermost planets in our solar system are known as the terrestrial planets. There are no rings on any of the terrestrial planets, though Earth does have trapped radiation bands, as explained below. Only Earth has a significant planetary magnetic field among the terrestrial planets. There are localised regional magnetic fields on Mars and Earth’s moons, but no global magnetic field.

The only terrestrial planets with significant atmospheres are Venus, Earth, and Mars. The gases found in a planet’s atmosphere are linked to its size, mass, temperature, how it formed, and whether or not life exists. In comparison to the gas giants, the terrestrial planets are all quite small. Furthermore, they have a definite surface, but no rings. They also lack the multiple moons found around gas giants.

Definition of Terrestrial Planets

A terrestrial planet, also known as a telluric or rocky planet, is a celestial entity with a solid surface made mostly of silicate rocks or metals. This separates them from gas giants, which are predominantly made up of heavier elements in various forms, as well as gases like hydrogen and helium.

Compositions of Terrestrial Planets

Mercury, Venus, Earth, and Mars have three layers: a metallic core, a silicate shell (mantle and crust), and a volatile envelope of gases, ices, and, in the case of the Earth, liquid water.

The prominent elements in each stratum are different. The mass and atomic proportions of oxygen, iron, magnesium, and silicon in chondrites, the building blocks of terrestrial planets, total 90 percent.

Classification of Terrestrial planet 

The four terrestrial, planets are:

1. Mercury

Mercury is the planet that is closest to the sun. Mercury rises or sets around two hours after the sun rises or sets. It can be found near sunrise or sunset, early in the morning or shortly after dusk. Mercury’s surface is extensively cratered. Surface temperatures range from 427 to 183°C. 0.99 is its specific gravity. Its rotational and revolutionary periods are 59 and 88 days, respectively.

2. Venus

Venus is the planet closest to the Sun. It is instantly recognizable. The majority of its atmosphere is made up of carbon dioxide. As seen from the planet, the sun will rise in the west and set in the east, respectively. It rotates every 243 days and takes 224 days to complete one orbit around the sun. On Venus, a day lasts longer than a year on Earth.

3. Earth

The third planet from the Sun is Earth. The moon is the sole natural satellite of the Earth. Earth is the only planet in the solar system where life has been discovered. Earth is the only planet with an atmosphere, and water covers roughly two-thirds of it. 

Nitrogen, oxygen, carbon dioxide, water vapour, and minor amounts of other gases are found in the atmosphere’s layers.

4. Mars

Mars is the fourth planet in the solar system. It’s a planet with a reddish hue. Viking spacecraft have probed Mars in search of signs of life. Some areas on Mars have a modest temperature range. It contains oxygen, nitrogen, and water. It contains ice caps towards the poles that look like caps of carbon dioxide. Phobos and Deimos are two of Mars’ natural satellites. Mars has a specific gravity of 0.72.

Characteristics of terrestrial planets

Terrestrial planets have the following characteristics:

• They have a smooth finish.
• They have a core that is made up of heavy materials.
• Because of the heavy metals, they have a larger density.
• They are not as big as the gaseous planets.
• They are in close proximity to the sun.
• There are not many moons. 
• Have a lower gravitational pull.

Conclusion

In this article, we learned that, Mercury, Venus, Earth, and Mars are known as terrestrial planets because they have a compact, solid surface similar to terra firma on Earth. The four innermost planets in our solar system are known as the terrestrial planets.

Its gravity binds the Solar System together, and its light shines on us, allowing us to survive. We would perish if the Sun did not exist. Other planets are influenced by the Sun.