NASA Cassini Final Images Reveal Strange Textures in Saturn's Rings That Scientists Can't Explain

Scientists have revealed fascinating details about Saturn's rings in a study which documents some of the closest ever observations of these majestic features.

The data was collected by NASA's Cassini probe, which ended its mission in September 2017 by plunging into Saturn after more than 20 years in space.

Nasa operators deliberately destroyed the probe—which was rapidly running out of fuel—to avoid the possibility that it would one day crash into one on Saturn's many moons while stuck in orbit, contaminating pristine environments that could conceivably harbor life.

Before it met its fiery end, Cassini made the closest ever flybys of Saturn, taking measurements with four different instruments in the space between the planet's rings and its cloud tops during a series of more than 20 "dives." The resultant findings, published in the journal Science, broaden our understanding of this complex ring system, according to the scientists.

For example, an instrument on Cassini known as the Visible and Infrared Mapping Spectrometer (VIMS) took observations that reveal new details about the composition of the rings—which previous research has shown mainly consist of water ice.

Cassini's latest measurements indicate that the rings (named A through G) lack ammonia ice and methane ice, as well as organic compounds—generally meaning any chemical that contains carbon.

"If organics were there in large amounts—at least in the main A, B and C rings—we'd see them," Phil Nicholson, Cassini VIMS scientist from Cornell University in Ithaca, said in a statement. "I'm not convinced yet that they are a major component of the main rings."

Cassini also snapped several images showing how tiny moons located within the rings, such as Daphnis, shape and influence the complex structures, creating strange wave-like patterns which have never been seen before.

"These new details of how the moons are sculpting the rings in various ways provide a window into solar system formation, where you also have disks evolving under the influence of masses embedded within them," Matt Tiscareno, lead author of the study and Cassini scientist from the SETI Institute in California, said in the statement.

The scientists also suggest that a series of streaks in the outer edge of the main rings were caused by numerous impacts with material that was orbiting the planet itself, and not the sun—for example, objects like comets and asteroids.

Furthermore, the Cassini data has revealed three distinct, newly identified textures—clumpy, smooth and streaky—in some regions of the ring system where there are belts of material with sharp edges, puzzling scientists. These textures appear to differ, even when they are found close together.

"This tells us the way the rings look is not just a function of how much material there is," Tiscareno said. "There has to be something different about the characteristics of the particles, perhaps affecting what happens when two ring particles collide and bounce off each other. And we don't yet know what it is."

Scientists are still poring over the data collected by Cassini, which is providing a much clearer picture of Saturn and its rings.

"It's like turning the power up one more notch on what we could see in the rings. Everyone just got a clearer view of what's going on," Linda Spilker, Cassini project scientist, said in the statement. "Getting that extra resolution answered many questions, but so many tantalizing ones remain."

Saturn rings, Daphnis
A false-color image mosaic shows Daphnis, one of Saturn's ring-embedded moons, and the waves it kicks up in the Keeler gap. Images collected by Cassini's close orbits in 2017 are offering new insight into the complex workings of the rings. NASA/JPL-Caltech/Space Science Institute