Unmistakable and instantly identifiable, the 6th planet from the Sun is one of the most unique planets our solar system has to offer. With an expansive ring system, dozens of Moons, and a churning atmosphere Saturn is an active and beautiful place.

The Planet

Saturn orbits 1.4 billion kilometres away from the Sun on average, taking just under 30 Earth years to do so.

Coming in at just about 9.5 time wider and approximately 95 times heavier than Earth, Saturn takes the place as the second largest and second most massive planet in the Solar System. Despite its size, Saturn has a similar gravitational attraction at its cloud tops to Earth’s gravity at sea level.

Saturn is the furthest object in the Solar System that can be viewed by the naked eye, and as such, was given its name by ancient Roman astronomers. Saturn was not seen in more detail than as a star in the sky until 1610, when Galileo Galilei used his telescope to make observations of the planet.

Saturn back-lit by the Sun. Source: NASA/JPL-Caltech/SSI

The Rings

Easily the most identifiable feature of Saturn is its rings. Despite being observed telescopically in 1610, Saturn’s rings weren’t observed until 1659 when Christiaan Huygens observed them with a sufficiently large telescope. In the centuries since, research and observation of the rings has revealed many unique structures, gaps and active processes within the system.

The gaps in Saturn’s rings are thought to be formed when a moon begins forming in the rings, known as a moonlet, or through gravitational resonances originating from other moons in the Saturnian system.

The rings themselves range from a few micrometres in thickness, all the way up to a few dozen meters thick on average, and stretch from 7,000km to 80,000km high above the planet’s equator. The rings are predominately made from water ice, reflecting most of the sunlight that hits them, allowing the ring system to be easily identified, even in amateur telescopes.

Titan's lakes of liquid hydrocarbon can be seen in this composite image. Source: NASA / JPL-Caltech / Space Science Institute

The Moons

At the time of writing, Saturn has a total of 82 moons, the most in the Solar System. Some of the most interesting and dynamic moons in the solar system can be found orbiting Saturn.

The icy moon Enceladus has cyrovolcanic plumes erupting from its south pole, blasting into space for hundreds of thousands of kilometres, and an underground ocean of liquid water. The giant moon of Titan is the only moon to have a thick, permanent atmosphere. This atmosphere, composed mostly of nitrogen and methane gas, is stable enough to support a moon-wide system of liquid hydrocarbons on the moon’s surface, the only place in the solar system where liquids are permanently found, other than on Earth.

An artist's impression of the Cassini spacecraft arriving at Saturn

The Missions

Saturn has been subject to many visits from interplanetary spacecraft throughout recent decades, first visited in 1979 by the Pioneer 11 space probe, which flew past the gas giant on its way out to deep space. Saturn was visited and studied by Voyager1 & 2 in the early 1980s. Both spacecraft took many images and scientific observations before continuing on in their missions.

Most famously of all is the Cassini/Huygens spacecraft, which entered orbit around Saturn in 2004 and spent 13 years making observations, taking images and performing experiments around the plane. Most modern information about the planet is due to the close up observations made by the Cassini/Huygens mission.

How do I see Saturn?

Saturn will be visible in the night sky just after sunset for the remainder of the year, approaching the western horizon the later in the year. A useful trick for finding this planet is to look for the brighter Jupiter and looking westward.

Riley Johnston

Riley is an experienced astronomy guide who has been working within the astronomy community for several years. He is incredibly passionate about the night sky and holds a Bachelor’s Degree in Science, Math and Education.

Riley Johnston


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