Saturn is the second largest planet in the solar system. It's also one of the four Jovian planets. It takes its name from a Roman god of agriculture. While other giant planets have rings, including Jupiter, Uranus and Neptune, Saturn's rings are the most extraordinary.
The planet's rings are filled with ice, dust and rock, and they orbit Saturn. The largest ring, known as the Phoebe ring, is bigger than Saturn itself. Way bigger. The Phoebe ring is about 100 to 270 times the radius of Saturn, which makes it about 3.75 million to 10.1 million miles (6 million to 16.2 million kilometers) from the planet.
For comparison, the average distance between Earth and its moon is 238,855 miles, or 384,400 kilometers. Once again, astronomy puts the human ego in check.
Saturn's rings may get all the attention, but we shouldn't ignore its other attributes. The sixth planet from the sun, Saturn also is the second largest in the solar system after Jupiter.
These two planets are in a league of their own. If you mushed every planet from Mercury to Neptune together, Saturn and Jupiter alone would account for over 90 percent of their cumulative mass.
Despite Saturn's mass, it is the least dense planet in the sun's orbit — and the least spherical, too. We'll need to look at its physical makeup to understand why.
ContentsResearch published in 2019 showed that a day on Saturn lasts just 10 hours, 33 minutes and 38 seconds. That makes it the second-shortest day in the solar system. Its spin rate helps explain one of its stranger qualities.
You see Saturn has a huge waistline. The planet's equator is 74,898 miles (120,536 kilometers) in diameter. Yet Saturn's pole-to-pole diameter is much smaller, equivalent to just 67,560 miles (108,728 kilometers). So in a manner of speaking, Saturn is 10 percent wider than it is tall.
Astronomers call that kind of disparity an equatorial bulge. Every planet in the solar system has one, but Saturn's is the most extreme. Spin an object — any object — and its outside edge will move at a faster rate than its center does. That's physics for you.
Saturn rotates around its axis at a very high speed; hence, the brevity of its days. And here's where density comes into play. Like Jupiter, Saturn is a gas giant. Such worlds predominantly consist of hydrogen and helium — and whereas Earth is solid on the outside, a gas giant is not. (It may, however, have a hard, solid core.)
Now Saturn is downright huge in terms of volume. Some 764 Earth-sized objects could fit inside it and the planet's 95 times as massive as our home world. And yet relative to its size, Earth is eight times denser.
In fact, water — yes, plain water — is denser than Saturn. (Although that doesn't mean the planet would float, contrary to popular belief.) Thanks to its low, low density and zippy rotation period, Saturn's been deformed into an oblong world that looks kind of squished in profile.
Jupiter has an ongoing storm called the Great Red Spot. The Saturnian system's answer to this is the "Great White Spots," periodic tempests that arise every 20 to 30 Earth years on Saturn's Northern Hemisphere. First detected in 1876, the weather events are colossal in scale.
NASA's Cassini spacecraft spent 13 productive years hovering around Saturn. On Dec. 5, 2010, it witnessed the most recent iteration of the Great White Spots phenomenon.
The storm was about 800 miles (1,300 kilometers) wide by 1,600 miles (2,500 kilometers) long when it first began.
But over the next six months, the "spot" expanded longitudinally until it had looped itself around the planet in a gigantic circle.
Some researchers think the Great White Spots might be part of a cycle that sees the outer layer of Saturn's atmosphere slowly lose heat, allowing the warm air from lower levels to burst upward.
Up at the Saturnian north pole, there's a cloud pattern shaped like a giant hexagon. This pleasantly symmetrical jet stream spins counterclockwise, measures about 20,000 miles (32,000 kilometers) across and includes a hurricane that's been swirling right over the pole ever since it was discovered back in 1988.
Of course, it's Saturn's rings that we all know. The gas giant owes its popularity to this stunning system encircling it.
Saturn isn't the only planet with rings.Jupiter, Uranus and Neptune have ring systems as well. Yet in terms of sheer scale, the network of icy rings around Saturn is totally unrivaled.
Saturn's ring system extends up to 175,000 miles (282,000 kilometers) from the planet, but just about 30 feet (10 meters) vertically. So proportionately, the gas giant's iconic rings are thinner than a typical sheet of writing paper, noted astronomer Phil Plait.
Most of the primary inner rings come with letter names. The closest to Saturn is called the "D" Ring, which has an inner radius of about 66,900 kilometers (41,569 miles). It's surrounded by the C, B, A, F, G and E Rings — in that order. By the way, Saturn's rings aren't arranged alphabetically because this naming system reflects the dates of their discovery. "A," "B" and "C" were sighted before the rest.
When measured from its outside edge, the "E" ring showcases an impressive 298,258-mile (480,000-kilometer) radius. Or at least, that looks impressive until you get to know the big bad Phoebe ring we mentioned earlier. First spotted in 2009, this one was named after a Saturnian moon.
Mostly water ice, rock and dust particles make up these rings. Some bits are the size of a sugar grain; others could probably dwarf your house. In any case, the ring material is stretched remarkably thin.
Whereas Saturn itself is probably around 4.5 billion years old, the age of its rings isn't as clear. Data from NASA's Cassini spacecraft, which studied the Saturn system between 1997 and 2017, suggest they formed between 10 million to 100 million years ago, when an icy comet — or some ice-covered moons — came too close to the planet.
The visitor(s) met a grisly end, getting ripped to pieces by Saturn's gravity. As those fragments collided, they grew smaller and multiplied, giving rise to the skinny system we all know today.
On the other hand, a 2019 paper argued the whole Saturnian system might've originated at an early stage in the history of our solar system. We'll have to see how the debate unfolds as new evidence arises.
No other planet in the solar system has more moons than Saturn — not even mighty Jupiter! As of June 8, 2023, Saturn has a confirmed 146 moons in its orbit. You can find Saturn's moons in, around and beyond the ring system. Before NASA's Cassini spacecraft was retired in 2017, it revealed that some of them gather clumps of dust and ice from the rings.
Arguably no Saturnian moon has attracted more interest than Saturn's largest moon, Titan. The solar system's second-biggest moon, Titan is the only moon in the solar system known to have clouds, seas and lakes. Titan's atmosphere also has rivers of liquid methane and ethane instead of liquid water.
There's only one other body within the sun's orbit that has standing pools of liquid. Here's a hint: You're sitting on it right now.
Titan is also noteworthy for having an atmosphere. And it's theorized Titan's atmosphere could have "ice volcanoes" that spew water instead of lava. Sounds like paradise.
Now That's CoolAs the second-largest planet in the solar system, Saturn is visible in the night sky with binoculars or a small backyard telescope. You can even Saturn's rings and its larger moons if the conditions are just right.
