With its gorgeous horizontal halo of rings, Saturn is probably the most all-around iconic planet when it comes to the general public. Indeed, the “Ringed Planet” may just be the signature “landmark” of outer space.
How much do you know about this instantly recognizable celestial body? In this Living Cosmos guide, I’ll run through a slew of fascinating facts about Saturn: from those spectacular rings to its impressive collection of moons.
So, without further adieu, let’s launch our way to the Ringed Planet and get to know it!
1. The Big Picture: Saturn Within Our Solar System
Saturn’s the sixth-farthest planet from the Sun. It spins about 886 million miles from our home star, past Jupiter and inward of Neptune’s orbit.
2. Gas Giant Indeed: Saturn’s Size
Saturn’s the second-biggest planet of all. Its diameter—not counting the far-reaching rings—spans about nine Earths lined up side-by-side. Saturn’s volume is equivalent to that of more than 760 Earths.
3. The Makeup of a Gas Giant: Saturn’s Structure
Like Jupiter, its gas-giant cousin, Saturn consists mainly of hydrogen and helium with a small rocky core. The predominantly hydrogen-helium composition of gas giants makes them somewhat similar to stars.
Saturn’s thick atmosphere gives it a pale, cloud-swirled look: sort of a duller version of Jupiter.
4. Saturn’s Short Days & Long Years
Saturn boasts the second-swiftest rotation in the Solar System (after its gas-giant neighbor Jupiter). Its fast spin around its axis gives the planet a day-length of roughly 10 hours, 15 minutes.
Given Saturn’s gaseous makeup, that speedy rotation also flattens the planet’s poles and bulges out its equator.
Though it experiences a much shorter day than Earth, Saturn takes much, much longer to orbit the Sun. A Saturnian year translates to about 29½ Earth years.
5. Seasons on Saturn
Like Earth, Saturn lies at a tilt to the plane of its rotation around the Sun. This gives Saturn seasons, with its northern pole sunlit for half the Saturnian year and its southern pole sunlit the other half.
This means that Earthbound observers see the top of Saturn’s rings illuminated for 15 Earth years, then the bottom for another 15. At the midway points—the equinoxes—the Sun hits Saturn’s equator head on.
During Saturnian equinoxes, we’re looking edgewise at the rings. During those brief interludes, therefore, they appear nearly invisible from Earth.
6. A Giant Featherweight: Saturn’s Density
Saturn is about 60 percent of Jupiter’s size but only a third or so of its mass. That hints at its low density.
Big as it is, in fact, Saturn claims the lowest density of any of the Solar System’s planets: about 0.68 grams per cubic centimeter, less than that of water.
In other words, if you could track down a big-enough swimming pool, fill it up, and plop Saturn in, the planet would float. (Good luck with that project…)
7. The Showstopping Rings of Saturn, Largest in the Solar System
Without question, Saturn’s rings are its most famous, most utterly eye-popping feature. All the other giant planets of our Solar System—Jupiter, Uranus, and Neptune—have their own rings. None, however, compare in size or splendor to Saturn’s. They span up to 175,000 miles (282,000 kilometers).
Though they add up to an enormous width, Saturn’s rings are thin: Their thickness averages only about 66 feet (20 meters). They’re mainly composed of water ice, with particles ranging in size from dust-like specks to house-sized chunks.
Named alphabetically in order of their discovery, Saturn’s main rings include (from nearest to farthest from the planet) the D, C, B, A, F, G, and E rings. The outermost of all is the extremely vague Phoebe Ring, named for its proximity to one of Saturn’s most far-flung moons.
8. Gaps in the Rings
Saturn’s rings aren’t evenly arrayed, with breaks in the rings forming dark bands between. The most significant of these is the Cassini Division, a nearly 3,000-mile gap between Rings B and A.
9. The Formation of Saturn’s Rings: A Bygone Moon?
Saturn’s rings are reckoned at about 100 million years old. How did they form? Well, astronomers aren’t 100% sure.
One long-held theory is that Saturn’s gravitational force pulled in a passing asteroid or meteor, which then broke apart approaching the planet and turned into a halo of debris. Others propose the rings represent material incorporated into Saturn’s orbit early in the formation of the Solar System itself.
Some researchers, meanwhile, have proposed that the rings represent the pulverized remnants of a bygone Saturnian moon. This hypothetical satellite even has a name: Chrysalis.
This theory suggests the larger moon Titan may have warped Chrysalis’s orbit toward Saturn.
In short order, tidal forces would have torn Chrysalis apart to produce the rings.
10. The Many Moons of the Saturnian System
Speaking of moons, Saturn’s got a lot of them. We’re talking 63 confirmed moons, with 20 others under consideration for “official” status.
That total of 83 (for now) puts Saturn second on the list when it comes to the moon hauls of our Solar System’s planets, a bit shy of Jupiter’s 92. (More moons of all sorts are being discovered throughout the Solar System on a regular basis, and Jupiter and Saturn have been neck-and-neck on this front for several years.)
These many natural satellites in the Saturnian system account for some amazing worlds in and of themselves. They’re intimately connected to Saturn’s rings, too. Many orbit within the rings, which also contain a slew of so-called moonlets.
And debris ejected off some of the moons helps “resupply” certain rings.
Biggest and most famous of Saturnian moons is Titan, which warrants its own fact section (read on!). Then there’s Enceladus, an “ocean moon” like Titan. Cassini documented icy water plumes off Enceladus that appear to feed the second-outermost ring of Saturn, the E-Ring.
The plumes jet from fissures on the glazed surface of Enceladus’s south pole, which scientists have called “tiger stripes.”
The Saturnian moon Iapetus, meantime, is famous for its two-toned look: one hemisphere bright, the other darkened. Iapetus lies inward of the moon Phoebe. It appears that Phoebe’s dust dirties the darker face of Iapetus.
11. Titan: Enigmatic Moon
The diameter of Titan proper is about 3,500 miles, making it by far Saturn’s biggest moon and, after Jupiter’s Ganymede, the second-biggest moon in the Solar System.
In fact, while Ganymede outsizes the solid ball of Titan by about two percent, Titan is actually larger if its enveloping atmosphere is included.
That atmosphere makes Titan unique: It’s the only known moon in the Solar System with its own. It’s also singular for the presence of liquid lakes of methane and ethane on its surface, fed by hydrocarbon rain.
Titan’s system of precipitation, lake formation, and evaporation is thought to be roughly equivalent to Earth’s water cycle.
And scientists believe that a subsurface ocean of liquid water hides beneath Titan’s icy crust.
12. Saturn’s Energy Budget
Saturn boasts quite the interior source of energy. It’s estimated that Saturn radiates twice as much energy as it receives from the distant Sun.
13. Winds of Saturn
Saturn’s a blustery place, to say the least. The Voyager missions documented prevailing easterly winds roaring about 1,100 miles per hour around Saturn’s equator.
14. Saturn’s Epic Storminess
Among the most impressive Solar System storms we know of go down on Saturn. The great ringed planet seems to build up energy within its thick, cloud-wrapped atmosphere that’s abruptly released in periodic thunderstorms.
Vertical air movements (convection) likely drive these lightning-rich Saturnian storms, as in Earth’s terrestrial thunderstorms.
The more commonplace storms on Saturn are updraft-driven disturbances mainly associated with the latitudinal belts of 35 degrees N and 35 degrees S.
The stormy belt of Saturn’s southern hemisphere, recognized first, was nicknamed “Storm Alley.” Among the most striking outbreaks in Storm Alley was the so-called Dragon Storm of 2004.
Less common but larger storms outside those storm belts, called Great White Spots, so-named because they appear as huge swirling white disturbances, seem to break out on the planet roughly once a Saturnian year. (In other words, every 29.5 Earth years.)
Roughly a couple thousand thunderstorms rumble away on Earth at any given moment in time. Several large storms roil Jupiter’s atmosphere concurrently. By contrast, Saturn usually sees just one storm at a time—but a doozy.
Saturnian thunderstorms are enormous: They’re often as much as 1,864 miles across (3,000 km). That’s significantly bigger than your average Jovian storm (less than 932 miles/1,500 km). And it utterly dwarfs the roughly 16-mile (25-km) diameter of a garden-variety terrestrial lightning storm on our planet.
Saturn’s greatest storms are larger yet: Great White Spots can be 6,214 miles (10,000 km) in north-south extent.
15. Snakes Eating Their Own Tails: Great White Spots & Their Planet-Spanning Influence
The Cassini spacecraft and terrestrial telescopes documented a particularly impressive Great White Spot that erupted in December 2010. This “Great Northern Storm,” as it was called, raged for months, as Great White Spots often do.
These biggest of Saturnian storms boast a broad, bright head that develops a long, longitudinally spreading tail. Sometimes, as with the 2010-2011 Great White Storm, that tail comes to encircle the planet.
We’re still learning about Great White Spots, but they seem to occur when Saturn’s northern hemisphere is tilted toward the Sun. One theory proposes that they represent a delayed bursting-out of convection ultimately resulting from seasonal cooling, rainfall, and density shifts of Saturn’s upper atmosphere.
Observations suggest Great White Spots such as the Great Northern Storm end up influencing Saturn’s atmosphere for a long time after they’ve ebbed. They’re probably linchpins of planet-wide atmospheric cycling.
How Far Apart Are Saturn and Earth?
At their closest “passes,” Earth and Saturn are some 746 million miles (1.2 billion km) apart. Hey, “only” 746 million miles!
How Did Saturn Get Its Name?
Though ancient observers and different cultures have given Saturn many different names, we’ve adopted the Ancient Roman one. It’s a nod to the god of agriculture, Saturn
Does Saturn Have a Nickname?
From one perspective, Saturn’s leading nickname is self-explanatory: the “Ringed Planet.” At the same time, it’s a misleading one: Jupiter, Neptune, and Uranus all claim their own rings—less spectacular though they may be.
Who Discovered Saturn’s Rings?
In 1610, Galileo Galilei admired Saturn through his telescope, but confused his poor view of the rings for flanking moons. It took a number of decades before somebody got a clear-enough look to actually identify Saturn’s rings: the Dutchman Christiaan Huuygen, in 1655.
Is Saturn Visible From Earth?
Saturn is indeed visible from Earth Even a relatively inexpensive, low-power telescope can yield a striking view of Saturn, including at least a blurry look at the rings. (I’ve even used a simple spotting scope, mainly a wildlife-watching tool, to eyeball the planet.)
A telescope of moderate power can even show off Cassini’s Division, that prominent dark gap in the rings.
Could You Stand on Saturn’s Surface?
No can do: Saturn’s surface is gaseous, not solid. You could not walk on its rings, even if you wanted to!