When Galileo observed Saturn through his telescope in 1610, he described what looked like two arms or two very large moons on either side of the planet. In a letter to the Duke of Tuscany he wrote, in essence, that Saturn was not alone but had two companions extremely close to it, apparently touching it, although Saturn itself was much larger.
Two years later, Saturn had moved to a point in its orbit where, from Earth's viewing angle, Galileo could no longer see the rings edge-on. Doubting his own eyes and thoroughly confused, he concluded that “Saturn has swallowed his two children,” connecting what he saw with the Roman myth of Saturn destroying his children for fear of being overthrown. Two years later, as Saturn's geometry changed again, Galileo once more saw the mysterious structures through his small telescope and was more puzzled than ever.
All dates in the original article were given in the Solar Hijri calendar; they are rendered here in their corresponding historical era where appropriate.
Years later, with more powerful telescopes, Dutch astronomer Christiaan Huygens explained that what Galileo had seen was neither moons nor arms but a very flat ring system surrounding Saturn without touching the planet. Cassini, Laplace, Maxwell, and Kovalevskaya were among the later scientists who advanced understanding of Saturn's rings before the modern era.
In the modern spacecraft era, Voyager 2 provided close observations and transmitted memorable images of Saturn's rings to Earth. The Cassini spacecraft, which at the time of this article was exploring Saturn from orbit, continued sending striking images and steadily increasing our knowledge of the rings.
Today, even a simple amateur telescope can show Saturn's rings more clearly and beautifully than Galileo could see them through his handmade instrument, helping us appreciate what he experienced.
The rings of the Solar System's other giant planets were discovered through somewhat similar, though perhaps less dramatic, stories. Uranus's rings were discovered in 1977 by James Elliot, Edward Dunham, and Douglas Mink. William Herschel had claimed more than two centuries earlier to have seen rings, though modern astronomers have questioned that observation because Uranus's rings are extremely dark and faint. Voyager 2 later returned clear images of them.
Jupiter's rings were first discovered and photographed by Voyager 1 in 1979. Images from the Galileo spacecraft between the mid-1990s and early 2000s greatly increased knowledge of them, and New Horizons also photographed Jupiter's ring system. The existence of rings around Neptune, which the article notes had been anticipated much earlier, was confirmed in the spacecraft era through Voyager 2 observations.
With modern tools—space probes, advanced ground-based observatories, and space telescopes such as Hubble—our understanding of the rings of Saturn, Jupiter, Uranus, and Neptune continues to grow.
And then, on March 26, 2014, a team of European scientists announced, from observations made on June 3, 2013, the completely accidental discovery of two narrow rings around the distant small body Chariklo, beyond Uranus's orbit. Before this discovery, the article emphasizes, nobody had expected such rings around an asteroid-like small body, much less deliberately searched for them.
Until a human spacecraft someday visits Chariklo, photographs its rings, and sends those images back, we must make do with artists' impressions. At that future time—somewhere in history, somewhere on Earth, or perhaps beyond it—someone will continue this story.
The accompanying collection shows drawings and images of Solar System planets and their rings, spanning historical depictions through the modern era.