Categories: Saturn

Cassini Images Ring Arcs Among Two of Saturn’s Moons

NASA’s Cassini spacecraft has imaged a faint, partial ring orbiting with one small moon of Saturn, and has confirmed the presence of another partial ring orbiting with a second moon. This is further evidence that most of the planet’s small, inner moons orbit within partial or complete rings. Recent Cassini images show material, called ring arcs, extending ahead of and behind the small moons Anthe and Methone in their orbits. The new findings indicate that the gravitational influence of nearby moons on ring particles might be the deciding factor in whether an arc or complete ring is formed.

Both Anthe and Methone orbit Saturn in locations, called resonances, where the gravity of the nearby larger moon Mimas disturbs their orbits. Gravitational resonances are also responsible for many of the structures in Saturn’s magnificent rings. Mimas provides a regular gravitational tug on each moon, which causes the moons to skip forward and backward within an arc-shaped region along their orbital paths, according to Nick Cooper, a Cassini imaging team associate from Queen Mary, University of London. “When we realized that the Anthe and Methone ring arcs were very similar in appearance to the region in which the moons swing back and forth in their orbits due to their resonance with Mimas, we knew we had a possible cause-and-effect relationship,” Cooper said.

Scientists believe the faint ring arcs from Anthe and Methone likely consist of material knocked off these small moons by micrometeoroid impacts. This material does not spread all the way around Saturn to form a complete ring, because of the gravitational resonance with Mimas. That interaction confines the material to a narrow region along the orbits of the moons.

This is the first detection of an arc of material near Anthe. The Methone arc was previously detected by Cassini’s Magnetospheric Imaging Instrument, and the new images confirm its presence.

Source: JPL Press Release

Nancy Atkinson

Nancy has been with Universe Today since 2004, and has published over 6,000 articles on space exploration, astronomy, science and technology. She is the author of two books: "Eight Years to the Moon: the History of the Apollo Missions," (2019) which shares the stories of 60 engineers and scientists who worked behind the scenes to make landing on the Moon possible; and "Incredible Stories from Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos" (2016) tells the stories of those who work on NASA's robotic missions to explore the Solar System and beyond. Follow Nancy on Twitter at https://twitter.com/Nancy_A and and Instagram at and https://www.instagram.com/nancyatkinson_ut/

Recent Posts

Here’s What We Know About Earth’s Temporary Mini-Moon

For a little over a month now, the Earth has been joined by a new…

58 minutes ago

New Study Suggests Black Holes Get their “Hair” from their Mothers

Despite decades of study, black holes are still one of the most puzzling objects in…

2 hours ago

Gaze at New Pictures of the Sun from Solar Orbiter

74 million kilometres is a huge distance from which to observe something. But 74 million…

2 hours ago

Are Fast Radio Bursts Caused by Interstellar Objects Crashing Into Neutron Stars?

Astronomers have only been aware of fast radio bursts for about two decades. These are…

7 hours ago

Here’s How to Weigh Gigantic Filaments of Dark Matter

How do you weigh one of the largest objects in the entire universe? Very carefully,…

9 hours ago

How Could Astronauts Call for Help from the Moon?

Exploring the Moon poses significant risks, with its extreme environment and hazardous terrain presenting numerous…

21 hours ago