\n Saturn and its rings, captured by the Cassini spacecraft<\/p>\n NASA\/JPL-Caltech\/Space Science Institute<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n Specks of dust from Saturn\u2019s rings appear to float much farther above and below the planet than scientists thought possible, suggesting the rings are more like a giant dusty doughnut.<\/p>\n The main structure of Saturn\u2019s rings is extremely thin, extending outwards for tens of thousands of kilometres but only vertically for around 10 metres, which creates the planet\u2019s striking appearance when viewed from Earth. There is some variation in this shape, however, such as the puffier outer E ring fed by Saturn\u2019s moon Enceladus, which spurts out ice from its underwater ocean.<\/p>\n <\/p>\n Now, Frank Postberg at the Free University of Berlin and his colleagues have analysed data NASA\u2019s Cassini spacecraft during 20 orbits in 2017, the mission\u2019s final year, when it took extremely steep paths through the rings, starting from distances up to three times Saturn\u2019s radius above the planet and sweeping to the same distances below.<\/p>\n Cassini\u2019s spectrometer, the Cosmic Dust Analyzer, found hundreds of tiny rocky particles near the top of Cassini\u2019s trajectory that had a similar chemical make-up to grains found in the main ring, which are low in iron. \u201cIt\u2019s a really distinct spectral type we never see anywhere else in the Saturnian system,\u201d says Postberg.<\/p>\n \u201cThere\u2019s much more stuff close to the ring plane, but it still is surprising that we see these ring particles that high, both above and below the ring plane,\u201d he says.<\/p>\n To get so high, more than 100,000 kilometres from the main ring, Postberg and his team calculated that particles would need velocities of more than 25 kilometres per second to escape Saturn\u2019s gravity and magnetic forces.<\/p>\n It is unclear what process might give them those speeds, says Postberg. The most straightforward explanation is that tiny meteorites smash into the rings and send particles flying, but this wouldn\u2019t produce fast enough shrapnel.<\/p>\n However, micrometeorites colliding with Saturn\u2019s rings could generate temperatures hot enough to vaporise rock, according to a recent study which suggested that Saturn\u2019s rings are far older than previously thought. Postberg and his colleagues suggest this vaporised rock can shoot out of the rings at far higher velocities than shrapnel and later condense at distances far from the planet.<\/p>\n To find dust so far from the main ring is surprising, says Frank Spahn at the University of Potsdam, Germany, who wasn\u2019t part of the study. This is because the particles in Saturn\u2019s main ring are small, making them collide infrequently, and sticky, so collisions tend to be more like snowballs hitting each other than billiard balls, he says.<\/p>\n Micrometeorite collisions happen all over the solar system, so the same thing could also be happening on other ringed planets, such as Uranus. \u201cIf you have high velocity impacts onto icy rings, then this process could be universal. You would expect similar dust halos above and below other rings,\u201d says Postberg.<\/p>\n Experience the astronomical highlights of Chile. Visit some of the world\u2019s most technologically advanced observatories and stargaze beneath some of the clearest skies on earth.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n Topics:<\/p>\n<\/section><\/div>\n![\"New](\"https:\/\/images.newscientist.com\/wp-content\/uploads\/2024\/11\/28003449\/shutterstock_1102540808-scaled.jpg\")
\n <\/picture>\nThe world capital of astronomy: Chile<\/h3>\n