Approaching Iapetus - what makes it two-faced?

[silylene old]

paulscottanderson: thanks, and I thought the same (see previous posts). It looks like ancient exuded material. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[3488]

What does Vogon13 make of this???<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[h2ouniverse]

Strange that it would have exuded in the ram direction and not towards Saturn, as one should expect from tidal bulge stress lines and an upsurge of water or ice.<br />The thermal gradient generated by the albedo differential might crack the shelf close to the center of the dark face. But then the ridge should be white, not under the dark deposit.<br /><br />That may leave two possibilities however that would be consistent with the internal origin:<br />* the ridge formed towards Saturn then Iapetus has rolled by about 90° (as envisaged for Enceladus), before the dark stuff deposited<br />* there have been several occurences of dark deposition; one has generated the thermal gradient hence upsurge and a white ridge, latter ones have covered the ridge with dark material<br /><br />What do you think of it?<br /><br />Regards.

 

[vogon13]

To 'precipitate' a ring system uniformly around 360 degrees of equator takes an atmosphere.<br /><br />Like Saturn.<br /><br />Or Jupiter.<br /><br /><br /><br />As we have noted here before, a ring encircling an airless body experiences differential shear motion, as individual ring particles at ajacent altitudes 'rub' or 'bump' each other.<br /><br />This process slowly (but relentlessly) transfers angular momentum from the inner edge of the ring system towards the outer. This results in a slow, even, and unifornm contraction of the inside radius of the ring.<br /><br />Now, we have an exquisitely circular, and ever so slowly contracting about an irregular object. It is basic geometrical logic, that such a contracting ring, can only contact an irregular surface at a <i><b>single</b></i> point. Contact with this point triggers emplacement of the ring materials. A point cannot extend the length of the equator, it is a point. So, we expect ring emplacement on an irregular object (such as Iapetus) to be keyed to that point. Therefore, we do not expect an even distribution of materials about the equator of an airless irregular body, such as Iapetus.<br /><br />And, amazingly enough, we find the emplaced rings materials on Iapetus to be <i><b>unevenly</b></i> distributed about the equator.<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>

 

[h2ouniverse]

Hi Brellis and all<br /><br />I am wondering whether such thermal regulation is not the explanation of Hyperion aspect too.<br /><br />If accumulation of hot materials increase temperature locally under sunlight, then ice below may vaporize. On a very fluffy ground like on Hyperion, can't this lead the floor of the dark spots to collapse progressively? with the spots descending, surrounded by steep slopes?<br /><br />http://photojournal.jpl.nasa.gov/catalog/PIA07741<br />http://photojournal.jpl.nasa.gov/catalog/PIA06245<br /><br />Best regards.<br />

 

[3488]

Hi Joel,<br /><br />For Hyperion, that is an accepted idea, that the darker crater floors absorb more sunlight, thus<br />making that crater floor warmer, than the surrounding area & it 'burns' deeper into<br />the surface. <br /><br />Also it appears that many craters on Hyperion are 'drilled in' because the impactors<br />met little resistance on impact. <br /><br />Both processes are likely the cause of Hyperion's deep craters & giving Hyperion that <br />spongey appearance.<br /><br />Talking of drilled in cratrs, that is what we see on much of the Voyager Mountains on Iapetus,<br />but not on the surface on either side, thus reinforcing the fact, that those mountains are made <br />from loose material.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[vogon13]

Another possibility for deep craters on Hyperion is perhaps in the distant past it was in closer proximity to Titan.<br /><br />Impactors accelerated by Titan's stronger gravity that encountered Hyperion on their way in would have made larger craters than had they been acceled by Hyperionian gravity alone.<br /><br /><br />{I am entertaining the idea Hyperion started out as sub-satellite of Titan, and was 'repelled' by Titanian tidal effects prior to Titan's achieving tide lock with Saturn. And Hyperion was thoroughly blasted during the experience.}<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>

 

[3488]

Hi Vogon,<br /><br />Do you really think that Hyperion was a Titan moon at some point? <br /><br />I have that feeling, that it may have been.<br /><br />Hi all,<br /><br />A couple of updates from NASA / JPL Planetary Photojournal.<br /><br />Iapetan mosaic.<br /><br />NASA / JPL flight over Iapetus.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[h2ouniverse]

To reconcile Vogon with the ones suggesting Titan was a planet captured by Saturn, and in coherence with the fact that no natural subsatellite has ever been observed, here is another speculation:<br /><br />Titan had two moons orbiting it, Hyperion and Iapetus, when it was captured by Saturn.<br /><br />I am not really believing it myself but may be this makes sense to the capture-ists?<br />

 

[3488]

I had never heard of that one Joel. <img src="/images/icons/crazy.gif" /><br /><br />Interesting idea. What needs to happen is for a grvity sim to be done to reproduce such<br />a scenario & see what the computations make of it.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[vogon13]

Back in the late seventies (IIRC) Sagan published the results of some early computer simulations done in modeling the formation of the planets of our solar system. I was never too enthralled with the results (especially after the 'hot Jupiters' started being discovered around other stars) but the simulation results I have often felt were applicable to some extent in outlining how big planets might have their moons arranged. <br /><br />Saturn's system seems rather 'mundane' amongst the simulated sytems when rescaled appropriately.<br /><br /><br />Additionally, we seem to be pretty sure Triton is a captured object, and it's capture and subsequent 'spin down' seems to have 'dissipated' or destroyed Neptune's existing satellite system. This does not seem to resemble Saturn/Titan at all.<br /><br /><br />Sorry . . . <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>

 

[vogon13]

Additionally:<br /><br />I am a 'fan' of certain moons having had subsidiary objects. And I feel we have tidally evolved objects available for study that were 'sub' moons long ago (Polydueces, Calypso, Hyperion, etc.).<br /><br />However, I also think a distinct mass ratio range is characteristic of such objects and their former primaries. Iapetus is orders of magnitude outside of the 'plausible' range of masses for expected Titanian 'sub' moons.<br /><br /><br />Sorry . . . . <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>

 

[h2ouniverse]

Fine for me.<br />But as no subsatellite has ever been spotted, that would have been imho the best chance for Hyperion to have ever orbited Titan...

 

[franontanaya]

The first time I saw the ridge it remembered me instantly the underwater tectonic expansion ridges we have here.<br /><br />Things I've been wondering:<br /><br />- If the migration of ice to the poles and the increase/loss of mass is creating, or created, any kind of tectonic stress.<br /><br />- If, being mostly an icy crust, that stress could bump an ecuatorial mountain chain or open a cryovolcanic ridge, if that makes any sense...<br /><br />- Also, if that stress could heat the icy inner Iapetus, and if a liquid layer could be effectively transferring the pressure at the poles to the equator.<br /><br />- If, in that case, the ridge is still growing during polar growth and sinking under its own weight during the other ages -at a low gravity geological pace- and if "stretched" very ancient craters could be distinguished from eroded/oblique craters.<br /><br />- If Iapetus was all-black before impacts or other events brought more ice to the surface. Also, how Iapetus climate would have been/would be if it was dark all around. <br /><br />- If the dark layer is very ancient, and it was just made slightly darker at Cassini Regio than at Roncesvaux Terra by the floating particles from other moons.<br /><br />- If the ancient Iapetus had a thicker ice crust, by the amount of dark stuff left, and somehow lost it during some dramatic age or event. Like, being a disturbed KBO that had some close passes to the Sun before parking around Saturn. It has a somewhat unusual orbit.<br /><br />- If, being an outsider, its surface is younger than it seems, and it's just showing the scars of "bullying" his space after rushing around Saturn.<br /><br />- Looking at the huge impacts, if Iapetus is a several moon-murderer and had something to do with the formation and composition of the rings, which now are still closing and falling into Saturn. <div class="Discussion_UserSignature"> </div>

 

[jaxtraw]

I'm fairly new here, should I call you Joel or your screen name? I don't wish to offend by being too familiar. <img src="/images/icons/smile.gif" /><br /><br />I'm inclined to think, as a "Capturist" (isn't it great how points of view become tribes?!) <img src="/images/icons/smile.gif" /> that perhaps we should see Titan more as a protoplanet than a planet, starved of greater bulk by the giants forming around it. I don't see it having significant satellites in that scenario; possibly a small lump like Hyperion that protoplanet-Titan itself captured, but Iapetus, I can't see that. None of the other small planets have large moons except Earth of course, which was the result of an unusual collision. Of course having said that, maybe Iapetus was cleaved from Titan similarly. Proving that would need some good samples of each though, wouldn't it?<br /><br />My 'umble guess would be that Titan's arrival pushed Iapetus out into its current orbit. But I must admit I don't know where the iapetan ring (which I'm a fan of) fits in with that.<br /><br />It's an interesting speculation though, the idea of Hyperion and Iapetus coming in with Titan. But to me, Iapetus looks a lot the rest of Saturn's family. Titan strikes me as the lone oddball (besides the various captured little moons and fragments).

 

[anthmartian]

I am still looking at those amazing images. Still reading any new post here also. I put this together today if anybody is interested.<br /><br />http://anthmartian.googlepages.com/iapetus-october22.jpg/iapetus-october22-full.jpg<br /><br />made from 3 separate channels. Not true colour at all. With layers enhanced to bring out more detail.<br /><br />More cassini stuff, and an archive of the fly-by here...<br /><br />http://anthmartian.googlepages.com/thisislandearth <div class="Discussion_UserSignature"> <p><font color="#000080"><em>"Traveling through hyperspace ain't like dusting crops, boy! Without precise calculations we could fly right through a star, or bounce too close to a supernova and that'd end your trip real quick, wouldn't it?"</em></font></p><p><font color="#33cccc"><strong>Han Solo - 1977 - A long time ago in a galaxy far far away....</strong></font></p><p><br /><br />Click Here And jump over to my site.<br /></p> </div>

 

[alokmohan]

What is a proto planet?I hear of proto sun.

 

[3488]

Hi alokmohan,<br /><br />A protoplanet is a planet during formation. <br /><br />Stars like Vega, Fomalhaut, Beta Pictoris, etc are thought to have protoplanets<br />orbiting them.<br /><br />Hope that helps.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[3488]

Hi Anthmartian,<br /><br />Yes I am interested (you knew I would be). Thank you very much for your continuing efforts with your<br />amazing images.<br /><br />I will download them once my system is up & running again.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[alokmohan]

Hi 3488,thanks.Does sun have a proplanet,either now or in past.

 

[3488]

Hi alokmohan,<br /><br />All of the Sun's planets would have been Protoplanets, during their formation,<br />even our own Earth was one once.<br /><br />As far as we know, there are no current protoplanets orbiting our Sun. There is a remote<br />posibilty of a larger planet slowly forming still, in the Kuiper Belt, but it is very unlikely.<br /><br />The planets in our solar system, with the possible exception of Mercury are evolving,<br />that is a different issue, but as far as we know, the Sun's planets are fully formed.<br /><br />BTW, you can call me Andrew.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[robnissen]

<font color="yellow">BTW, you can call me Andrew. </font><br /><br />I thought this was like Get Smart, instead of Agent 86, you are Agent 3488. <img src="/images/icons/smile.gif" /> BTW, none of my business, but I was wondering about the significance of that number?<br />

 

[3488]

Latest Iapetus Map.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[3488]

<p><font size="5">Atlas of Iapetus.</font><br /> <img src="http://sitelife.space.com/ver1.0/Content/images/store/14/0/ce7a9628-ce23-403f-a09d-5f99865ab6db.Medium.jpg" alt="" /><br />&nbsp;</p><p><font size="2"><strong>Fascinating.</strong></font></p><p><font size="2"><strong>Andrew Brown.&nbsp;</strong></font></p> <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[silylene old]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Atlas of Iapetus. &nbsp;Fascinating.Andrew Brown.&nbsp; <br />Posted by 3488</DIV><br /><br />Thanks.&nbsp; Yes, very fascinating and a good link with maps. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>