Sur­prises at Saturn

Cassini found out much about the ringed planet, but ex­perts weren't ex­pect­ing these

All About Space - - Results From Cassini -

Cassini's fi­nal plunge

To en­sure that Cassini didn't con­tam­i­nate any of Saturn's moons, the mis­sion ended its 13 years of ser­vice via a con­trolled en­try into the gas gi­ant's at­mos­phere. It's here that the space­craft broke up as it plunged through the lay­ers and lay­ers of gas, suc­cumb­ing to the planet's pres­sure.

More go­ing on be­tween its rings

It might look empty be­tween its rings and its sur­face, but there's much more go­ing on here than ini­tially sus­pected – that's be­cause of a con­nec­tion be­tween the up­per at­mos­phere and the gas gi­ant's crown­ing fea­ture: stream­ing elec­tric cur­rents that flow be­tween the rings and the outer at­mos­phere. How­ever, it's not clear what's caus­ing them or why they're there; that's some­thing that the Cassini mis­sion will help us to fig­ure out. And that's not all – it's thought that there's also a belt of ra­di­a­tion that's com­ing from trapped en­er­getic par­ti­cles be­tween the rings and the planet.

Strangely flat mag­netic field

Un­like the other outer plan­ets in our So­lar Sys­tem that have tilted mag­netic fields, Saturn's is per­fectly straight and, ac­cord­ing to our un­der­stand­ing of how these fields are made, this shouldn't be pos­si­ble: ac­cord­ing to the Cassini team it's the tilt that keeps the mag­netic field from dy­ing away. How­ever, be­fore the space­craft plunged into the at­mos­phere it dis­cov­ered that this wasn't the case – in fact, it could sug­gest that the ringed gi­ant is gen­er­at­ing its mag­netic field in a dif­fer­ent way, per­haps with many onion-like lay­ers of flow­ing par­ti­cles in­stead of a sin­gle zone.

Saturn’s rings rain ma­te­rial

Saturn's in­ner­most rings rain the equiv­a­lent of 1,800 cars per minute in tiny par­ti­cles onto its at­mos­phere – un­sur­pris­ingly, it's called ring rain. Cassini un­cov­ered that around Saturn's equa­tor this rain de­posits some 45,000 kilo­grams of ice, dust and gas ev­ery sec­ond, and it could mean that the rings are dis­ap­pear­ing much more quickly than we ini­tially thought. And, be­cause the rain is made up of am­mo­nia, ni­tro­gen, meth­ane and other such com­plex or­ganic par­ti­cles, it could be that the Saturn's top lay­ers are be­ing af­fected chem­i­cally.

Cassini team mem­bers at NASA’s Jet Propul­sion Lab­o­ra­tory re­ceive data from thefirst of Cassini’s Grand Fi­nale fly­bys

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