Saturn’s “A Ring” May Be Running a Temperature

- 08 Sep 2015

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Perhaps one of the most fascinating attributes of Saturn is its rings. Children as well as adults have marveled at this planet’s circular “girdle” but now we have even more to ponder with the discovery of significant temperature changes on Saturn’s “A ring” which scientists are coining “a fever.”

The Equinox Effect

Saturn is tilted on its axis and experiences a 29-year orbit. As a result the Sun moves back-and-forth in a North to South direction across Saturn’s body and rings. And just as the equinox marks the changing of seasons here on Earth, researchers have also discovered it has been warming up the outermost ring (the A ring) of this celestial wonder.

Ryuji Morishima of NASA’s Jet Propulsion Laboratory, Pasadena, California, who led the study says;

“For the most part, we can’t learn much about what Saturn’s ring particles are like deeper than 1 millimetre below the surface. But the fact that one part of the rings didn’t cool as expected allowed us to model what they might be like on the inside.”


The planet Saturn, viewed by NASA’s Cassini spacecraft during its 2009 equinox. Image credit: NASA/JPL/Space Science Institute.

Saturn Rings With “Snow”

The rings of this planet are made up of trillions of tiny icy particles, so it’s not unusual to expect some variation of temperatures with the movement of the Sun; however, with the help of a team of Cassini scientists, new data has now opened up a window to the interior structure of Saturn’s rings.

Researchers dug in and performed an intense investigation on exactly how Saturn’s rings warm and cool during its seasons. Previously, based on Cassini data, Saturn displayed fluffy snow-like particles on the outside of its rings. This is called “regolith” and is created over time as small impacts pulverise the particles.

So why the slight “fever” on the A ring?

The best explanation the scientists are giving is the ring must have larger chunks of ice than previously suggested. In fact, they are proposing the particles are not so tiny, but more likely to be around three feet (1 metre) wide and made up of mostly solid ice, with only a thin coating of regolith.

Morishima explains; “A high concentration of dense, solid ice chunks in this one region of Saturn’s rings is unexpected. (The) Ring particles usually spread out and become evenly distributed on a timescale of about 100 million years.”

But this explanation brings up more questions like, could Saturn have once had another moon that suffered a collision leaving behind unevenly distributed debris on its rings? Or perhaps smaller moonlets are distributing ice chunks as they migrate around the rings?

Linda Spilker, Cassini project scientist at JPL and a co-author of the study had this to add;

“This particular result is fascinating because it suggests that the middle of Saturn’s A ring may be much younger than the rest of the rings. Other parts of the rings may be as old as Saturn itself.”

Only time will tell as Cassini is online for its final close orbit to Saturn in hopes of measuring the mass of this planet’s main rings for the first time ever. This will then allow scientists to gauge the age of Saturn’s mysterious rings.

More Saturn Facts

The “rings” around Saturn are not its only attribute. Here are some more interesting Saturn factoids;

  • Saturn is the sixth planet in our Solar System
  • Saturn is the second largest planet in our solar system
  • Saturn is the farthest planet visible to the naked eye
  • Saturn is considered a gas giant that is made up of mostly helium and hydrogen
  • Saturn has approximately 95 Earth masses
  • Saturn is a fast spinner completing a rotation every 10.5 hours.
  • Saturn bulges in the middle. In fact, the planet is 8,000 miles (13,000 kilometers) wider at its equator than between the poles.

Saturn just keeps on surprising us and someday maybe we will have all of its mysteries solved. Until then we will continue to peer up and study this wondrous planet, holding it in its well-deserved splendid awe.

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