Image credit: NASA/JPL-Caltech/Space Science Institute/University of Leicester

Saturn's system of rings is unarguably the thing that make the planet so mesmerizing to astronomers and amateurs alike. And it doesn't hurt that the rings themselves are very prominent. Not only are they captivating, but they are also extremely interesting from a scientific perspective, as there are yet still many unknowns about their formation, duration, and their future.

 

As such, we are consistently learning new facts about these rings. So unsurprisingly, something new was recently uncovered. As it turns out, water may not be nearly as scarce in our solar system as some believe it to be... the stuff was observed to be falling into the atmosphere of the ringed planet.

 

Image Credit: Messagetoeagle (Source)

The NASA-funded study analyzed the "rain" of charged water molecules that fell into the giant planet's atmosphere, before pooling into large areas in the upper atmosphere of Saturn, revealing that rain has a significant influence on both the composition of the planet, along with the temperature. This is the first instance of seeing a true connection between the atmosphere of a gas giant and its system of rings.

 

“It turns out a major driver of Saturn’s ionospheric environment and climate across vast reaches of the planet are ring particles located 120,000 miles [200,000 kilometers] overhead,” said Kevin Baines, a co-author on the paper from NASA's Jet Propulsion Laboratory. “The ring particles affect which species of particles are in this part of the atmospheric temperature" he continued.

 

According to James O’Donoghue, the study's lead author, the rain ring reduced the electron densities in the regions in which it falls, helping to 'quench' the ionosphere of Saturn, one of the outermost layers of the planet's atmosphere, where ionization takes place through interactions between particles in the atmosphere and solar radiation. This layer of protection plays an important role in atmospheric electricity, which in turn helps generate the planet's magnetosphere.

 

Saturn's Bands (source)

The concentration of electrons in the atmosphere has been of interest to scientists for some time now. Mostly because the density we had observed for decades prior to this find was unusually low at certain latitudes of the planet -- which was discovered when Voyager took the very first up-close observations of Saturn, revealing the tapestry of dark bans present in the atmosphere. After the bans were observed at infrared wavelengths, it was surmised that Saturn is host to trace amounts of water in its atmosphere, but the reason for the presence of the water remained a mystery. Until a few years later, when the cryovolcano plumes were seen on the Saturnian moon, Enceladus. The plumes have been observed shooting jets of water ice from Enceladus' south pole, forming a ring of water vapor around Saturn.

 

The bands in infrared

However, the bands first seen by voyager were not observed again for many years, until 2011, when astronomers got a good look at them using a near-infrared spectrograph , when the emissions were seen on the brightest parts of Saturn's atmosphere. Thus confirming the formation of the bands and the origin of the water vapor.

 

Hopefully the Cassini-Huygens spacecraft, currently orbiting Saturn as we speak, will be able to make more precise observations over the coming months before the spacecraft is decommissioned, doomed to be destroyed as it takes a death plunge into Saturn's atmosphere. One thing is for sure: Cassini will leave behind a huge legacy, as it has helped scientists to better understand the individual components of Saturn's system of rings, moons and atmosphere.


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