In its final days, Cassini bathed in 'ring rain'

[Binary_Bark]

On its last orbits in 2017, the long-running Cassini spacecraft dove between Saturn's rings and its upper atmosphere and bathed in a downpour of dust that astronomers call "ring rain."
In research published today in Science, CU Boulder's Hsiang-Wen (Sean) Hsu and his colleagues report that they successfully collected microscopic material streaming from the planet's rings.

"Our measurements show what exactly these materials are, how they are distributed and how much dust is coming into Saturn," said Hsu, lead author of the paper and a research associate at the Laboratory for Atmospheric and Space Physics (LASP).

The findings, which were made with Cassini's Cosmic Dust Analyzer and Radio and Plasma Wave Science instruments, come a little more than a year after the spacecraft burned up in Saturn's atmosphere. They stem from the mission's "grand finale," in which Cassini completed a series of risky maneuvers to zip under the planet's rings at speeds of 75,000 miles per hour.

Read more at: https://phys.org/news/2018-10-days-cassini.html#jCp

 

[Gordon_R]

https://www.bbc.com/news/science-environment-46911945

We're looking at Saturn at a very special time in the history of the Solar System, according to scientists.

They've confirmed the planet's iconic rings are very young - no more than 100 million years old, when dinosaurs still walked the Earth.

The US-European Cassini mission promised to resolve the argument in its last months at the gas giant.

The satellite's end days saw it fly repeatedly through the gap between the rings and the planet's cloudtops.

These manoeuvres made possible unprecedented gravity measurements.

From Cassini's other instruments, they already knew the proportion of dust in the rings and the rate at which this dust was being added. Having a definitive mass for rings then made it possible to work out an age.

 

[Binary_Bark]

Living as they do in the distant, sun-forsaken reaches of the solar system, Jupiter and Saturn, the gas giants, and Uranus and Neptune, the ice giants, were always expected to be frosty realms. But when NASA’s Voyager spacecraft sailed past them in the late 1970s and 1980s, scientists found that all four worlds were running planetary fevers — a revelation as jarring as finding a bonfire inside your freezer.


Follow-up observations by ground-based telescopes and the Galileo and Cassini spacecraft demonstrated that their planet-wide fevers have persisted through time. Their planetary pyrexias are acute: Jupiter’s lower latitudes, for example, should be a frigid −110 degrees Celsius. Instead, the atmosphere there cooks at 325 degrees. What incognito incinerator is behind this? And how is this unknown heat source warming not just a single spot on the planet, but the entire upper atmosphere?

https://www.quantamagazine.org/cassini-data-solves-jupiter-and-saturns-energy-mystery-20210622/