Jovian Planets

Beyond our Solar Systems' first asteroid belt, four massive Planets are located. These are known as the Outer or Jovian Planets. Jovian Planets are any Jupiter-like Planets which means that in our Solar System, these four Planets are known as Jupiter, Saturn, Uranus, and Neptune. These Planets are known as the Gas (Jupiter/Saturn) or Ice (Uranus/Neptune) Giants of our Solar System.

Characteristics of a Jovian Planet:

  • Made of gasses, primarily hydrogen and helium with varying amounts of other elements.
  • They don’t have a solid surface.
  • Are further from our Sun so they are considerably colder than the Terrestrial Planets.
  • They have lots of Moons. This is because they all have stronger gravitational forces that dominate a large area, making it easier for them to capture objects and keep them in a stable orbit around the Planet.
  • Are not habitable or suitable for life as we know them.
  • Have rings that surround the Planets. These rings are made up of ice, rock, and dust particles.
  • They all have fierce winds and storms.

They are a lot bigger than Terrestrial Planets. Jupiter is roughly 11 times larger than Earth, Saturn roughly nine times larger, Uranus and Neptune are both roughly four times larger than Earth

Photograph © NASA
Jupiter – Photograph © NASA
Saturn – Photograph © NASA


Named after the King of the Gods (Roman), he is the fifth planet from the Sun. He has the largest Moon in the Solar System. Ganymede is larger than Mercury. If it was orbiting our Sun rather than Jupiter, it could have been classed as another Planet, rather than as a Moon. It is also the only moon known to have its own magnetic field.  The European Space Agency is planning on launching a probe in 2023 to increase our understanding of Jupiter and three of his icy Moons – Ganymede, Callisto, and Europa. The Jupiter Icy Moons Explorer (JUICE) mission is looking at these Moons as they are all thought to have significant amounts of water beneath their surfaces, which could potentially make them habitable and possibly support life.


Named after the God of Agriculture (Roman). The father of Jupiter. The sixth planet from the Sun. Saturn is known for his bright, beautiful rings. Did you know that he is slowly losing his rings? Don’t worry it will take millions of years for this to happen. Nasa scientists have confirmed that Saturn’s rings are slowly being pulled towards the Planet. His powerful magnetic field pulls this ring rain of dusty, ice particles, enough to fill an Olympic-sized swimming pool towards the Planet every thirty minutes. It does make you wonder if the other Jovian Planets once had rung as impressive as Saturn’s that have slowly been pulled towards their respective Planets leaving the smaller, less impressive rings we find around them today.

Photograph © NASA
Photograph © NASA
Neptune – Photograph © NASA


Named after the God of the Sky (Greek). The seventh planet from the Sun.  He is the only planet named after a Greek God.  His name comes from the Latinized version of Ouranos, the grandfather of Zeus (Greek version of Jupiter), and the father of Cronos (Greek version of Saturn).   One of the earliest recorded sightings of Uranus was by John Flamsteed in 1690 but he thought it was a star and called it 34 Tauri.  It was William Herschel in 1781 using a homemade telescope that it was confirmed that this star was in fact a Planet making him the first Planet to be found using a telescope and the first planet discovered since ancient times.  Uranus is tilted at 98 degrees (Earth is 23 degrees). Scientists think that this is a result of a massive object, colliding with him, billions of years ago. They also think that this impact may be responsible for some of the Planets Moons.


Named after the God of the Sea (Roman). The eighth and last planet in our Solar System. The only spacecraft to have visited Neptune is Voyager 2 in 1989. It took Voyager 2 to twelve years to reach Neptune.  It studied Neptune’s rings, and atmosphere and also captured some spectacular pictures of a tempestuous world. One of the most unexpected things Voyager 2 discovered was a Great Dark Spot, a fierce rotating storm system, similar to Jupiter’s Great Red Spot. Unlike Jupiter’s Spot, a storm that has been raging for centuries Neptune’s storm spots have much shorter lives. When the Hubble Space Telescope observed Neptune in 1994, they noticed that the spot was gone.  Scientists think, that if the storms move too close to the Planets equator it causes them to dissipate. The Hubble Space Telescope has since found and observed other dark spots in Neptune’s Northern Hemisphere. It’s still unclear how these spots form.

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About The Author

Written by Emma Summers

Emma Summers is an EcoTraining Camp Manager at Selati Game Reserve.