Thursday, October 09, 2008

Enceladus Near-Miss

On October 9 Cassini passes within 25 km of Enceladus! This moon was subject of one of this blog's earliest posts on June 2006, Here Be Dragons.

"In 2005 our Cassini spacecraft made some amazing discoveries about Saturn and her moons. The moon Enceladus has a volcanic "hot spot" centred on its South Pole. The pole, which should be the coldest region on the moon, is the hottest! This spot emits an enormous plume of vapour which maintains Saturn's E Ring. Old theories of radioactive decay or tidal stress can not explain this hot spot.

"Enceladus' core and behaviour can be modelled with a central singularity of 10^12 kg. This mass is typical for a primordial singularity. This object consumes only 2.8 kg per year and generates 10^9 watts of radiation. Water and other molecules near this centre are heated to a plasma. Electrons are stripped from atoms, and the resulting ions are drawn into circular orbits. The resulting current generates a magnetic field with the 'positive' pole in the South.

"Electrons and positively charged ions spiral along magnetic field lines to form bipolar jets, the classic sign of a singularity. The Northern jet is composed of electrons which are absorbed by the moon's interior. More energetic ions of the Southern jet penetrate these layers to warm the South Pole. Escaping ions spiral into space, exactly as observed by Cassini.

"Unless Saturn's Rings are replenished, they would decay within 100 million years. Then we would face the anthropic question of why they exist in the right time for humans to view them. Thanks to the Cassini spacecraft, we have witnessed the E Ring being resuppllied from a moon. This observation suggests that similiar processes maintain the rings indefinitely."

Last December at the AGU Meeting, scientist Jennifer Meyer pointed out that tidal forces could not account of Enceladus' heat. Last month in Heavy Rings we learned that Saturn's Rings are heavier and longer-lived than previously thought, exactly as predicted. Scientists have long wondered about the origin of planet's internal heat and magnetic fields. A Black Hole within Enceladus has applications for many worlds, including Earth.

Check out the new Carnival of Space!

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