From the October 2002 issue

The hidden treasures of Saturn’s rings

This activity will give you close-up views of Saturn's ring system.
By | Published: October 26, 2002 | Last updated on May 18, 2023

When Galileo Galilei aimed his telescope at Saturn in 1610, he saw what looked like ears protruding from the planet’s disk. Two years later, the “ears” (which Galileo called stars) had vanished. Galileo never learned what they were, but today school children know about the beautiful set of rings which orbit Saturn’s equator. These rings tilt with the planet’s axis, causing them to occasionally appear edge-on and “disappear” from our vantage point on Earth.
The Changing Angle of Saturn's Rings
The 27-degree tilt of Saturn’s axis provides a changing look at the planet’s beautiful rings. The planet’s northern hemisphere had just passed its autumnal equinox when the Hubble Space Telescope captured the view of Saturn in the lower left in October 1996. In November 2000, when the image at the upper right was taken, Saturn’s northern hemisphere was approaching its winter solstice.
NASA / Hubble Heritage Team (STScI / AURA) / R.G. French / J. Cuzzi / L. Dones / J. Lissauer
In the centuries since Galileo made his telescopic observations of the Ringed Planet, other astronomers – and spacecraft – have studied Saturn’s rings and found a plethora of treasures within them.

The ring system is not a single ring but composed of several bands, each containing numerous ringlets. Jean Dominique Cassini first spotted the dark division splitting what astronomers now call the A and B rings, and later, faint rings were found in the Cassini Division itself. Johann Encke found another, thinner division in the A ring, which we call the Encke Gap (or Encke Division). Astronomers have since identified two rings within the B ring (closer to Saturn) called the C and D rings, and three beyond the A ring called the F, G, and E rings.

Saturn’s rings and ringlets also are not solid, but composed of tiny chunks of ice and rock. Keeping those ring particles in place are small moons which lie in the gaps between the rings. Pan lies in the Encke Gap, while Atlas and Prometheus lie between the A and F rings. Pandora guards the outside of the F ring, as Janus and Epimetheus orbit farther out, but still within the G ring. Mimas lies outside the G ring, and many more moons reside inside the wide E ring.

This activity will allow you to get a closer look at the rings and moons that make up Saturn’s gorgeous ring system. The scale of the E ring is so large (up to four Saturn diameters from the planet), that only the rings and moons inside its orbit are shown. All of the images are from NASA’s two Voyager missions, which flew past Saturn in the early 1980s. (Note: Images of Atlas, Prometheus, Janus, and Epimetheus are copyrighted by Calvin J. Hamilton.)

Click on the link below to launch the interactive activity.
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