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.
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.
Titan is home to seas and lakes filled with liquid hydrocarbons, but what forms the depressions on the surface? A new study using data from the joint NASA and European Space Agency (ESA) Cassini mission suggests the moon’s surface dissolves in a process that’s similar to the creation of sinkholes on Earth.