Difference Between Terrestrial and Jovian Planets

In the Solar System, there is one star, eight planets, and one dwarf planet. However, what many people are not aware of is that these eight planets are divided into two categories which are known as Terrestrial Planets and Jovian Planets.

The group of Terrestrial Planets consists of Mercury, Venus, Earth, and Mars. In the group of Jovian Planets, there lies Jupiter, Saturn, Uranus, and Neptune.

So, how do these planets actually differ?

To understand this difference, we need to look into the composition of these planets. Terrestrial Planets have a solid surface whereas Jovian planets have a gaseous surface. 

Terrestrial vs Jovian Planets

The difference between Terrestrial and Jovian Planets is that Terrestrial Planets have a solid, rocky surface while Jovian Planets have a gaseous surface.

Theoretically, the Terrestrial Planets, have a surface, similar to that of Earth’s, having a metallic core and a surface that has a vast amount of silicate materials. On the other hand, Jovian Planets constitute mainly of gases.

The gases present in major amounts are ammonia, hydrogen, helium, and methane. These planets supposedly have a molten rock as its core though. 

Comparison Table

Parameters of Comparison	Terrestrial Planets	Jovian Planets
Main Difference	Terrestrial Planets have a solid surface.	Jovian Planets are primarily gas covered planets.
Abundant Gases	Carbon Dioxide and Nitrogen.	Hydrogen, Helium, Ammonia.
Core	Usually a dense metallic core.	A comparatively less dense, molten rock core.
Density	The overall density of the planet is high and more compared to Jovian Planets.	The overall density of the planet is low and lesser than Terrestrial Planets.
Examples	Mercury, Venus, Earth, Mars.	Jupiter, Saturn, Uranus, Neptune.

What are the Terrestrial Planets?

Terrestrial Planets can also be called Telluric planets. Both the words, terrestrial and telluric have a Latin origin from the words terra and tellus, both of them mean Earth.

It is, however, important to understand that when we say Earth, we do not mean the planet Earth, but the solid, rocky nature of the planet Earth. Terrestrial Planets have a rocky, solid surface made up primarily of metals and silicate substances which are quite similar to the surfaces found in Earth, asteroids, etc.

Examples of Terrestrial Planets are Mercury, Venus, Earth, and Mars.

One important characteristic of terrestrial planets is that none of them possess rings. We can see rings present around Saturn, but that is a Jovian Planet and we will come to that later.

Terrestrial Planets can possess magnetic fields, but none of the terrestrial planets possess a global magnetic field, which means, none of them have a unified magnetic field all around it.  The moons of Mars and Earth have localized magnetic fields, but Earth is the only planet having a global magnetic field.

Among all the terrestrial planets, only Earth, Venus, and Mars have an atmosphere that is significant. The atmosphere of Mercury does not have any solid constitution, this is due to its proximity to relentless solar winds. 

Also, among all the Terrestrial Planets, so far, Earth is the only planet that has been known to harbor life. This is due to its optimum location and distance from the Sun, thus resulting in an ambient temperature and having the perfect gaseous combination in its atmosphere to sustain life.

What are the Jovian Planets?

The word Jovian mean Jupiter-like. This is because Jupiter is a gigantic gaseous planet and all the remaining planets, which are Jovian in nature, are gigantic in size as compared to the size of Earth and are largely constituted of gases.

A major amount of these gases are mainly Hydrogen, Helium, and traces of some other gases and ices. These planets still have a solid core, which is usually a solid molten rock.

These planets are characterized by a gaseous constitution, rings, and a lot of satellites. The Jovian Planets are also referred to as ‘Gas Giants’.

The planets lying in this category are Jupiter, Satur, Uranus, and Neptune.

A significant characteristic of Jovian Planets is the large numbers of satellites they possess individually. What is interesting is that one would expect that these moons would have similar characteristics.

However, the moons of Jovian Planets have such vast characteristics, that they can be categorized into groups of themselves as well. Discussing the rings of these planets, they are mostly myriad particles of ice, ranging from sizes of small specks of dust to large boulders.

These rings are a marvel of physics, as they have a very complex way of interacting with gravity and electrical charges.  Although this has been observed easily, however, it is worth mentioning that the Terrestrial planets are present in the inner part of the Solar System and the Jovian Planets are present in the outer part of the Solar System.

Main Differences Between Terrestrial Planets and Jovian Planets

1. The main difference between Terrestrial Planets and Jovian Planets is that Terrestrial Planets have a solid and rocky surface, with a dense metallic core. Jovian Planets have a large gaseous composition and a small, molten rock core.
2. The most abundant gases present in Terrestrial Planets are Carbon Dioxide and Nitrogen. The main gases present in Jovian Planets are Helium, Hydrogen, and Ammonia.
3. Terrestrial Planets usually have a dense metallic core, whereas Jovian Planets have a less dense molten rocky core.
4. Terrestrial Planets have an overall high density while Jovian Planets have a low density compared to Terrestrial Planets.
5. Examples of Terrestrial Planets are Mercury, Venus, Earth, and Mars. The planets under Jovian Planets are Saturn, Jupiter, Uranus, and Neptune.

References

1. https://www.sciencedirect.com/science/article/abs/pii/0019103573900195
2. https://www.annualreviews.org/doi/abs/10.1146/annurev.aa.18.090180.000453