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2014 Essay Contest: Winner, Target 1, Grade 9 - 12

2014 Essay Contest: Winner, Target 1, Grade 9 - 12

Ben Wolman
Saturn's F ring
Target 1, Saturn's F ring
Ben Wolman

Palisades Charter High School
9th Grade
Pacific Palisades, California

Teacher: Sarah Rosenthal

"On the outskirts of Saturn’s exotically beautiful ring system lies the planet’s F ring, a narrow band of surprising dynamism and mystery. This enigmatic ring is offering up novel insights to planetary dynamicists and astrophysicists alike. Flanked by the dense A ring closer to Saturn and the thin G ring farther out, the F ring is an anomaly among its icy colleagues, a unique result of gravitational interactions between nearby masses.

But gravity may not be the sole driver of the activity that birthed and maintains the tenuous F ring. Saturn’s magnetic field has been posited to stimulate even weakly charged particles in its rings to orbit, generating undulations in the ring similar to those produced by gravity. This creates the strange appearance of lace-like swirls. And closer inspection, thanks to groundbreaking Voyager flybys in 1980 and 1981, reveals even more remarkable peculiarities, further examined with unprecedented clarity at Cassini’s arrival mid-2004.

Voyager’s discovery of the affectionately termed “shepherd” moons, Pandora and Prometheus, surprised scientists when they realized the position of the moons on either side of the F ring allow them to act as cosmic sculptors, molding rocky debris into a narrow, defined ring. But peculiarities arise from the moons’ irregular orbits, and their forces on the ring particles also do damage, counteracting their neat shepherding and creating channels within the ring. Still smaller channels, or fans, have been observed in the F ring, probable signs of moonlets and other clumps of matter shaping the ring.

Astonishing as these extraordinary features of the ring are, the closer NASA scientists and other researchers look, the more they reveal within the F ring’s dominion. Particularly incredible are the “mini jets” spotted by Cassini that emanate from the F ring. Moving at the leisurely pace of about 2 m/s, these snowy trails, which resemble the ice-covered thorns of a rose vine, can span 40-180 km, and may be the consequence of collisional debris pummeling through ring material. One step in a continuous chain of satellite interactions, mini jets are victors in a game of gravitational tug-of-war. Further analysis of these majestic frosty streams could bring us closer to understanding the proto-planetary collisions that brought into existence our own planet, Earth, and its solar system siblings.

The recent discovery of the potential moon “Peggy” in Saturn’s A ring serves as a reminder that Saturn – not to mention our knowledge base – is still evolving. The F ring’s inimitable activity may itself prove the ultimate subject of study, with Cassini bringing to light interactions never before seen on other rings.

Saturn’s F ring is a kind of testing ground, then, from which information can be extrapolated to describe countless astrophysical situations. A petri dish of the cosmos, this ring is a window to the evolution of solid bodies, explaining how they coalesce and develop. The Cassini mission, with its dedicated team of scientists at the helm, will delve deeper into these questions and, undoubtedly, raise many more in years to come."