In its final year, Cassini plunged where no spacecraft had plunged before, down in the space between Saturn and its rings. Again and again it is deaf, for a total of 22 orbits. The data collecting during those breakneck dives, astronomers have just found new information about the way tiny moons sculpt and carve those rings.
It is, they say, not only new evidence that Saturn's rings are much younger than the planet, but also a window into the way planets form in the giant rings of dust and debris that circle newborn stars.
The new data, collected using four of Cassini's instruments, show the rings in more detail than ever before.
"It's like turning the power up one more on what we could see in the rings. Everyone just got a clearer view of what's going on, "said Cassini Project Scientist Linda Spilker or JPL-NASA. "That extra resolution has many questions, but so many tantalizing ones remain."
They reveal the delicate straw-like textures and clumps within the rings, and patterns produced by the movement of the shepherd moons, such as Daphnis. Scientists also have new maps of the colors, temperatures and chemistry of the rings.
In turn, this information answers some intriguing questions. For instance, a series of streaks generated by impacts in the F ring ̵
This includes flock of impactors that is orbiting Saturn, not a heavy or rogue cometary debris in orbit around the Sun.
The data also ponied up on some new information about Daphnis. The shepherd moon's shenanigans in its clear lane we call the Keeler gap are already pretty well documented, but new images have revealed thin strands of ring material separating from the crests in the moon's wake.
The problem is, so the textures cannot be linked to any feature of the rings.
"This tells us the way the rings look is not just how much material there is, "said astronomer Matt Tiscareno of the SETI Institute.
" There is something different about the characteristics of the particles, perhaps affecting what happens when two rings particles collide and bounce off each other.
"And I don't know what it is."
There were more mysteries in the ring's chemistry, revealed by Cassini's Visible and Infrared Mapping Spectrometer. 19659003] In the outermost part of the ring, the spectral map revealed an abundance of weak water ice. This is a surprise, because the region is highly reflective, which usually indicates water ice or high purity, or strong water ice. it is so reflective is a puzzle.  And the spectral analysis also detected no methane or ammonia ice in the rings. This is also a head-scanner, since last year scientists had found, among other organics, ammonia and methane raining down on Saturn from its inner ring.
But that's OK. Because, even though the probe's mission ended almost two years ago now, there is a lot more Cassini data yet to be unraveled.
"We see so much more, and closer up, and we're getting new and more interesting puzzles, "said astronomer Jeff Cuzzi of NASA.
" We are just settling into the next phase, which is building new, detailed models of ring evolution – including the new revelation from Cassini data that is much younger than Saturn. " 19659003] Better hurry though. In 100 million years, those glorious rings might be entirely gone.
The research has been published in Science .