Spokes!

[CalliArcale]

At last, Cassini scientists have spotted spokes in Saturn's rings. The spokes were a huge surprise and a major mystery from the Voyager images of Saturn. But instead of clarifying matters, Cassini has only deepened the mystery because in all the time it's been looking at Saturn, it hasn't recorded any spokes at all....until now.<br /><br />These spokes are not as obvious as those in the Voyager images, and it's not clear at all why it's been so hard to find them again. It just goes to show that there is a heck of a lot still to explore in the Saturn system.<br /><br />Finally . . . Spokes! <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[Philotas]

What are these spokes? Do we have a clue? <div class="Discussion_UserSignature"> </div>

 

[jmilsom]

That's wheely amazing!<br /><br /><img src="/images/icons/tongue.gif" /><br /><br />Are these spokes very short-lived? Do they alter in real time? A number of ideas have popped into my head, but I think that more info is needed. <div class="Discussion_UserSignature"> </div>

 

[vogon13]

Would that create a spoke like feature that would be intermittent? And that would also persist for (presumably) millions if not billion of years?<br /><br /><br />Resonance of Hyperion orbit with Titan also precludes computer simulations of Hyperion's past trajectory, so there won't be any means of verifying such a scenario.<br /><br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>Are these spokes very short-lived? Do they alter in real time?<p><hr /></p></p></blockquote><br /><br />Those are good questions, but unfortunately nobody really knows. The fact that Cassini didn't spot any of them until now suggests that they may be short-lived -- but then, there may also be something to do with observational conditions as well, as when Voyager saw lots, it was near the Saturnian equinox, and right now Saturn is moving away from a solstice, greatly influencing the angle of sunlight on the rings. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[jatslo]

Volcanism from a icy moon is shooting jets into the rings maybe?

 

[rhodan]

polarwanderer,<br /><br />I was thinking something like that too. Saturn is not the vacuum cleaner Jupiter is, but its gravity will surely catch a lot of passing-by material. The larger chunks, comets, could leave a visible trail in the Saturn's rings just before they are absorbed by the gas giant. <br /><br />Just guessing.

 

[Philotas]

Interesting theory. Thanks! <br />The upcoming flyby of Hyperions may aid us in this case. <div class="Discussion_UserSignature"> </div>

 

[vogon13]

The change in velocity (and the resultant change in kinetic energy of a body the size of Hyperion) necessary to modify a hypothetical Saturn ring approaching orbit of Hyperion to the present orbit which is entirely exterior of Titan's orbit is enormous and unlikely to occur.<br /><br />And then to have this orbit change so finely tuned so as to result in a path subject to resonance capture by Titan is unlikely multiplied by unlikely.<br /><br />And to do this with out apparently affecting Mimas, Prometheus, Rhea, Ymir, et al, further pushes the likelihood down.<br /><br /><br />Other than that, go for it.<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[igorsboss]

Just a wild guess.... as I haven't even seen the new data yet, but....<br /><br />The Voyager spokes images made me think that these spokes resembled, well... ground fog, actually. Now, I know ground fog can't be right, but that's what they reminded me of...<br /><br />These spokes seemed to form along the line at which Saturn eclipses the ring material. Then, as the ring material rotates away at different velocities, the spokes obliterated themselves.<br /><br />So, I think *something magical* happens when the rings move from shadow into sunlight, probably related to temperature change, so that a line of gaseous haze forms, which we interpret as a spoke.<br />