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International Edition Winners - 2012: India, Target 1, Grade: 10

International Edition Winners - 2012: India, Target 1, Grade: 10

Dhruv Kumar
Target 1, Pan
Dhruv Kumar

St. Paul's School (I.C.S.E.)
10th Grade
Begusarai Bihar

Teacher: Madhumita Ganguly

"Pan - the innermost known satellite moving in circular orbit just about 80,000 kilometers above the cloud tops of Saturn. Pan's Orbit lies just in the middle of the Encke gap- a ringlet around the Saturn. This moon was discovered on 16th July 1990 and christened PAN on 16th September 1991 after the Greek God of Shepherds because it was doing job of a shepherd- shepherding the ring particles to keep the Encke gap empty. The moon measuring about 20 km from pole to pole, has extraordinary shape, almost like a UFO, with equatorial ridges as high of almost 6 to 10 km.

It is thought that the gravitational field of Pan kicks out dust and ice particles from the Encke gap. It may also sweep out the dust particles in that region. So either the dust particles are kicked out or captured by the Pan. It is surmised that equatorial ridge or bulge is made up of such particles.

While Pan is not only shepherd moon –A couple of shepherd moons further out are supposed to maintain the braided F Ring and keep on changing its shape, Pan apparently acts alone for producing the Encke gap. One should note that the Encke gap is not completely empty- there are 3 thin rings within this gap. The rings and small shepherd inside the rings are enigmas; the mechanisms of their formation and their disposal are still being debated.

Early theories suggested that the rings are cosmologically speaking, temporary and can vanish quickly, being unstable but some recent theories have suggested that it maybe stable with lifetime of billions of years and maintained by shepherd moons and other forces like Electromagnetic interaction with other larger satellites. Watching Pan in details will provide some interesting clue to ring phenomena.

Pan may thus provide a real time view of early stages of planet formation- a kind of unprecedented cosmic laboratory. Taking a snapshot of Pan will be awesome by view of beauty and also by point of study. It will provide new views and ideas on shepherd moons and rings of Saturn.

There are quite a few things that need explanations:

  • The shape of the satellite.
  • How it keeps the ENCKE gap clear, while still maintain 3 sharp faint rings inside the gap.
  • The dynamics of acceleration and particle ton by tidal effects need to be studied.
Shape of Pan also suggests that it may not have condensed out of rings (in which case it would have been roughly spherical) but is a part of a previously destroyed body like an asteroid or a comet which have been captured by Saturn and broken up and Pan is a small rocky part of it."