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Credit: NASA/JPL/Space Science Institute

"X-rays show clearly where electric currents are flowing near Saturn.
The presence of X-rays both outside and inside Saturn's rings show
that current is being transferred across the rings. Prometheus is
participating in that discharge."


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Dec 09, 2004
Prometheus Steals the Ring, or Forges It

In Greek legend, Prometheus steals fire from the gods to give to man. Unfortunately the story is misunderstood because the "fire of the gods" was electrical. The similarity of an electric discharge to fire lies in the fact that both are a plasma. However, an electrical discharge in a plasma may be invisible, unlike most flames. There is a plasma discharge mode known as a "dark discharge". It may be felt as a wind, or movement of particles in the direction of the electric field. It will be familiar as the breeze from an air ionizer.

Pictured above is Saturn's little moon Prometheus, nestled inside the gas giant's F ring. The report accompanying the image says, "In an image taken on Oct. 29, Prometheus is seen stealing particles from the F ring while connected to the ringlets by a faint streak of material.

" ... Scientists are not sure exactly how Prometheus is interacting with the F ring here, but they have speculated that the moon might be gravitationally pulling material away from the ring. Scientists speculate that the ring particles may end up in a slightly different orbit from the one they were in prior to getting a 'kick' from the moon. These kicks occur at specific locations in the rings and can actually cause large waves or knots to form. In the still image, gaps in the diffuse inner strands are seen. All these features appear to be due to the influence of Prometheus in ways that are not fully understood."

It is unlikely that the influence of tiny, potato-shaped Prometheus on Saturn's F ring can be understood in purely gravitational terms. A giveaway to the electrical nature of the interaction can be seen in the spiky projections, or "faint streaks", projecting from the F ring toward Prometheus. Faint streaks like that are seen in comet tails, which are also an electrical discharge phenomenon.

But is Prometheus stealing material from the rings or is it losing material to the rings in a comet-like electrical discharge? Is Prometheus undergoing electric discharge machining (EDM) and providing fine dusty material for the F Ring? The same process could account for the odd discovery that Saturn's A and B rings are clean water ice while the Cassini division between them is very dirty. There was probably a small moon orbiting there which has recently been machined to dust.

If this model is correct we should expect to see a freshly cratered surface on Prometheus, rather like that of Comet Wild 2, if the opportunity arises to see Prometheus more closely.



David Talbott, Wallace Thornhill
Amy Acheson
  CONTRIBUTING EDITORS: Mel Acheson, Michael Armstrong, Dwardu Cardona,
Ev Cochrane,   Walter Radtke, C.J. Ransom, Don Scott, Rens van der Sluijs, Ian Tresman
  WEBMASTER: Michael Armstrong

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