"It's incredible! There are hundreds of them!" exclaimed the astronomers who met in the control room of the Jet Propulsion Laboratory in Pasadena, where they were receiving "live" pictures transmitted from the American probes. It was November 10, 1980. Voyager 1 was about to reach its closest point to Saturn, which would occur on November 12 at a distance of 102 000 kilometers. Its television cameras had been focused on the planet for the last three months. The pictures continued to flow into the Nasa center faster and faster: at the end of the mission a total of 17 500 photographs would have been taken, and most of them would be processed in color by the powerful American electronic computers. The rings became clearer and clearer on the screens as the researchers became more and more excited. They showed the classic rings A, B and C, which theoretically should have been separated (at least this is what was indicated by the studies and observations from the Earth) by large empty spaces, the so-called "divisions": instead, each one was found to consist of hundreds of smaller rings. Even the divisions contain many rings, though much less dense: the Cassini division, that dark space that can be easily seen even in photographs taken from Earth-bound telescopes, contains at least five separate rings. Ring F, one of which was shown by Pioneer 11, consists of at least three separate rings. In other words, researchers today have been presented with a planet surrounded by an immense, more or less continuous disk of matter: rings and divisions appear as such only in relation to the greater or lesser thickening of the disk and are lighter or darker depending on the average dimensions of the particles of which they are formed. Voyager instruments analyzed this last aspect and discovered that, even in terms of dimensions, the matter around Saturn is not uniformly distributed: the classic rings visible also from the Earth (and which, going from the outer to the inner areas are named A, B and C) also contain masses with very large dimensions. Scientists then asked themselves: why is the matter that forms the rings distributed around Saturn with this structure? Why is it thicker in certain areas than in others? The television cameras provided the obvious answer that came from ring F. Looking closely at is entire development, researchers noticed that there were two unknown moons at its edges: one with a diameter of 200 and the other 220 kilometers. Evidently, it must be the gravitational attraction exerted by these two small moons that keeps the ring together, like two sheep dogs with their flock: this is why they were called the "shepard moons". This seemed to be the most plausible hypothesis. And it would have remained as such for many years if Voyager 2 hadn't reached Saturn a few months later, on August 27, 1981: after successfully completing its mission on Jupiter, Voyager 2 (Voyager 1's twin) had been "reprogrammed", making slight changes to the trajectory and its scientific assignments based on the information received from its predecessor. The second probe also passed under the rings and then, focusing on a star, measured the effects on the light produced by this star when crossing the rings: naturally, the denser the matter in the rings, the harder it is for light to pass. The result was amazing: there were no longer hundreds, but thousands of rings. These very thin formations followed each other like the incisions on a microgroove. And like incisions, some of them are interconnected, winding like an immense spiral around Saturn. Voyager 2 tried in vain to find new lines which justify the greater or lesser thickness of the rings. But there were absolutely no trace.
"It's incredible! There are hundreds of them!" exclaimed the astronomers who met in the control room of the Jet Propulsion Laboratory in Pasadena, where they were receiving "live" pictures transmitted from the American probes. It was November 10, 1980. Voyager 1 was about to reach its closest point to Saturn, which would occur on November 12 at a distance of 102 000 kilometers. Its television cameras had been focused on the planet for the last three months. The pictures continued to flow into the Nasa center faster and faster: at the end of the mission a total of 17 500 photographs would have been taken, and most of them would be processed in color by the powerful American electronic computers. The rings became clearer and clearer on the screens as the researchers became more and more excited. They showed the classic rings A, B and C, which theoretically should have been separated (at least this is what was indicated by the studies and observations from the Earth) by large empty spaces, the so-called "divisions": instead, each one was found to consist of hundreds of smaller rings. Even the divisions contain many rings, though much less dense: the Cassini division, that dark space that can be easily seen even in photographs taken from Earth-bound telescopes, contains at least five separate rings. Ring F, one of which was shown by Pioneer 11, consists of at least three separate rings. In other words, researchers today have been presented with a planet surrounded by an immense, more or less continuous disk of matter: rings and divisions appear as such only in relation to the greater or lesser thickening of the disk and are lighter or darker depending on the average dimensions of the particles of which they are formed. Voyager instruments analyzed this last aspect and discovered that, even in terms of dimensions, the matter around Saturn is not uniformly distributed: the classic rings visible also from the Earth (and which, going from the outer to the inner areas are named A, B and C) also contain masses with very large dimensions. Scientists then asked themselves: why is the matter that forms the rings distributed around Saturn with this structure? Why is it thicker in certain areas than in others? The television cameras provided the obvious answer that came from ring F. Looking closely at is entire development, researchers noticed that there were two unknown moons at its edges: one with a diameter of 200 and the other 220 kilometers. Evidently, it must be the gravitational attraction exerted by these two small moons that keeps the ring together, like two sheep dogs with their flock: this is why they were called the "shepard moons". This seemed to be the most plausible hypothesis. And it would have remained as such for many years if Voyager 2 hadn't reached Saturn a few months later, on August 27, 1981: after successfully completing its mission on Jupiter, Voyager 2 (Voyager 1's twin) had been "reprogrammed", making slight changes to the trajectory and its scientific assignments based on the information received from its predecessor. The second probe also passed under the rings and then, focusing on a star, measured the effects on the light produced by this star when crossing the rings: naturally, the denser the matter in the rings, the harder it is for light to pass. The result was amazing: there were no longer hundreds, but thousands of rings. These very thin formations followed each other like the incisions on a microgroove. And like incisions, some of them are interconnected, winding like an immense spiral around Saturn. Voyager 2 tried in vain to find new lines which justify the greater or lesser thickness of the rings. But there were absolutely no trace.
