A global ocean lies beneath the icy crust of Saturn’s geologically active moon Enceladus, according to new research using data from NASA’s Cassini mission. Researchers found the magnitude of the moon’s very slight wobble, as it orbits Saturn, can only be accounted for if its outer ice shell is not frozen solid to its interior, meaning a global ocean must be present.
NASA’s Cassini mission scientists were watching closely when the Sun set on Saturn’s rings in August 2009. It was the equinox — one of two times in the Saturnian year when the Sun illuminates the planet’s enormous ring system edge-on — providing an extraordinary opportunity for the spacecraft to observe short-lived changes that reveal details about the nature of the rings.
Saturn’s 698-mile-wide moon Dione crosses the face of the giant planet in a phenomenon known as a transit. Transits play an important role in astronomy and can be used to study the orbits of planets and their atmospheres, both in our solar system and in others. By carefully observing and timing transits, scientists can more precisely determine the orbital parameters of planetary moons.
Researchers at Kobe University have used computer models to reveal that Saturn’s F Ring and its shepherd satellites are a natural outcome of the final stage of the planet’s satellite system. This new finding is expected to help elucidate the formation of satellite systems both within and outside our solar system.
As dusk fades to dark on Saturday, 22 August, observers in the British Isles and Western Europe with clear skies can see the first quarter Moon close above planet Saturn low to the southwest. But for those skywatchers with binoculars and small telescopes, an additional treat is in store as the Moon passes in front of (occults) a naked-eye star.
A pockmarked, icy landscape looms beneath NASA’s Cassini spacecraft in new images of Saturn’s moon Dione taken during the mission’s last close approach to the small, frozen world. Two of the new images show the surface of Dione at the best resolution ever. Cassini passed 295 miles (474 kilometres) above Dione’s surface at 7:33pm BST on 17 August 2015.
Researchers at Southwest Research Institute (SwRI) and Queen’s University in Canada have unravelled the mystery of how Jupiter and Saturn likely formed using computer simulations. The discovery, which changes our view of how all planets might have formed, also suggests that the gas giants in the solar system probably formed before the terrestrial planets.
While not bursting with activity like its sister moon Enceladus, the surface of Saturn’s moon Dione is definitely not boring. Some parts of the surface are covered by linear features, called chasmata — bright icy cliffs among myriad fractures — which provide dramatic contrast to the round impact craters that typically cover moons.
NASA’s Cassini spacecraft will zip within 295 miles of Saturn’s moon Dione on Monday, 17 August — the final close flyby of this icy satellite during the probe’s long mission. After close flybys of other moons in late 2015, Cassini will depart Saturn’s equatorial plane to begin a year-long setup of the mission’s grand finale: repeatedly diving through the space between Saturn and its rings.
An international team of scientists has solved an age-old scientific riddle by discovering that planetary rings, such as those orbiting Saturn, have a universally similar particle distribution. The study also suggests that Saturn’s rings are essentially in a steady state that does not depend on their history.
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