Approaching Iapetus - what makes it two-faced?

3488 · Sep 11, 2007

Good Morning silylene, Where are those? The most recent ones I've seen are the ones I have linked to & cropped, etc above, three posts up, before Vogon's? Andrew Brown. <div class="Discussion_UserSignature"> "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". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

silylene old · Sep 11, 2007

I was referring to the linked pictures in this thread. p.s. Currently it is 'good afternoon', as I am in the Taipei airport, about to head off to another Asian facility. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center">- - - - - - - - - - - - - - - - - - - - - - </div><div class="Discussion_UserSignature" align="center">I really, really, really miss the "first unread post" function. </div> </div>

3488 · Sep 11, 2007

So it is Good Afternoon to you. I like eastern Asia, well the little that I have seen so far of it. Where are you off too? Somewhere nice hopefully. Thank you for your answer. I am following this with a tooth pick, I wondered if I had missed something new that you had found. Anyway, if you have time, please check back later. Much of the Iapetus data is to be transmitted twice, due to this encounter being a primary mission objective & considered among the 'highest priorities' of the four year primary mission. Also most images are expected to be here before late afternoon here in the UK or very early morning where you are. We will then get the SAR swathe too. I hope to talk to you again soon & we can exchange ideas (hopefully with Vogon & others who wish to join in too) with what has happened here. Once again, thank you. Have a good & safe trip. Andrew Brown. <div class="Discussion_UserSignature"> "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". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

anthmartian · Sep 11, 2007

I have uploaded all the latest images posted by Andrew. They are now on the Iapetus Encounter page here... http://anthmartian.googlepages.com/iapetusencounter Really well done Andrew. <img src="/images/icons/smile.gif" /> I like that crater a lot. With the central peak. None of these images are telling me that much, but i am enjoying them hugely. i look forward to reading more ideas, and theories about this moon. Fingers crossed for more images soon. It just goes to show how interested people are in this encounter. yesterday was the busiest day ever on my web site. With twice as many views as the previous best ( which also featured iapetus data ) <div class="Discussion_UserSignature"> "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?"Han Solo - 1977 - A long time ago in a galaxy far far away.... Click Here And jump over to my site. </div>

3488 · Sep 11, 2007

Thank you very much Anthmartian. I got up very early, to check & found those few, so i uploaded them, rotated, cropped, enhanced them, the best I could. They look really good on your site. So thank you very much. Just can't wait for the others, that's all. There are no fresh images since those earlier, but there should be many more within only a few hours. Hopefully, we'll get some really high reso shots of the Voyager Mountains, hopefully revealling once & for all, of what nature they really are. So far they look extremely pitted, so the cratering damage may not help. We should also get the SAR imaging too, strange that it will not be Titan, but Iapetus. I am more than happy to share somre ideas. Already I have done some of my own analysis, but really still need some more close up images. What I can say for sure, with the small grab bag that we currently have, is that the ice crust is extremely strong (I suspect very thick), it is not elastic & / or thin like Enceladus or Jupiter's Europa, but more like Jupiter's Callisto, Saturn's Rhea & Uranus's Oberon (Iapetus is just slightly smaller than Rhea & Oberon, but with Oberon, I do suspect ancient, now extinct cryovolcanism was evidenced by Voyager 2, where as Iapetus shows no such evidence as yet). Evidence is deep floored flat floored craters, whilst some slumping is visible, the crust appears rigid & strong, & I think even some thick layering in the walls of one or two larger craters. Yet to see some real close ups of the Voyager Mountains. I will return later if everyone can cope with my inane ramblings!!! Andrew Brown. <div class="Discussion_UserSignature"> "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". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

MeteorWayne · Sep 11, 2007

Well, with the SDC picture ability shut down, your site is one of the best places to see the images we are talking about. <img src="/images/icons/smile.gif" /> Thanx!! <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

CalliArcale · Sep 11, 2007

<blockquote>In reply to:<hr />I do not know how long it takes for the images to appear on the Web?? <hr /></blockquote> From following a few of the previous flybys, I've noticed that they seem to upload them in chunks. That is to say, a few dozen will show up at the same time, then there will be nothing for a while, then another batch will appear. I suspect that uploading to the web is therefore a lower priority task, probably done as spare time becomes available for the person who does the JPEG conversion and posting to the website. Which means they tend to be least timely during a flyby, ironically, because everybody is busiest then. <img src="/images/icons/wink.gif" /> There are only five new ones since I checked midday yesterday, though some of hte new ones are being rather stubborn about actually loading. I'm not sure if that's a problem at JPL's webserver, or my crappy work Internet connection (which has been known to conk out in the middle of loading a dynamically-generated page). <div class="Discussion_UserSignature"> "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." -- The Tenth Doctor, "Blink" </div>

vogon13 · Sep 11, 2007

The JPL/Cassini site has some new closeups of the Iapetan surface. Weird spherish lumpy things seem to be scattered all about. Trying to imagine a physical process that could generate rounded forms and them strew them across the surface . . . . <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

MeteorWayne · Sep 11, 2007

I believe they are actually shallow rounded craters with your mind (and mine BTW) inverting the perspective. The lighting is coming from the "wrong" direction so the eye-mind system seems them as lumps instead. I'm going to save the image and rotate it 180 degrees to see if I'm right. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

MeteorWayne · Sep 11, 2007

Yes, I believe I am. If you rotate the image 180 degrees you can see they are shallow, soft craters. I believe it is this image that Andrew posted above. (1378 km) already rotated. It's funny how the optical system works when shadows come from the direction we don't expect. <img src="/images/icons/cool.gif" /> <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

vogon13 · Sep 11, 2007

LOL, can't believe I fell for that. Just seeing what I wanted to see, perhaps . . . . <img src="/images/icons/laugh.gif" /> <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

MeteorWayne · Sep 11, 2007

Like I said, the functioning of the eye-brain visual system is a fascinating subject in it's own right <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

3488 · Sep 11, 2007

Hi all, Just a quick appearance for now. I will elaborate & answer CalliArcale properly later. I will say thank you all for showing interest in my contributions here.. Voyager Mountains from 8,040 KM Wide Angle. Voyager Mountains from 8,871 KM Narrow Angle. Voyager Mountains from 8,316 KM Narrow Angle. Iapetus from 7,226 KM Wide Angle. I will be back later. Andrew Brown. <div class="Discussion_UserSignature"> "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". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

vogon13 · Sep 11, 2007

Sections of the ridge have a cross section like this: . . . ._ ___/ . _______ (ignore periods) The 'sharpness' of the shoulders would seem to me to be non-extruded. And the flat top to the thing seems rather 'unextruded' too . . . . <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

MeteorWayne · Sep 11, 2007

2 new images released here the last 2 on Sept 11. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

anthmartian · Sep 11, 2007

*laughing at Vogons diagram* the lengths we are now going to with no image posting... we're back in the stone age!!! ...almost. lol* Some of the latest imagery, including Andrews Voyager mountain crop, and a few i have just finished tinkering with are now on my site. Encounter Page : http://anthmartian.googlepages.com/iapetusencounter Front Page : http://anthmartian.googlepages.com/thisislandearth MeteorWayne : Thanks for that, it has been a real pleasure to help share this event with everybody. There is nothing like contributing and helping out like minded, appreciative people. <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> "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?"Han Solo - 1977 - A long time ago in a galaxy far far away.... Click Here And jump over to my site. </div>

brellis · Sep 11, 2007

I see that our Time Lady has, like Picasso and Miles Davis, entered a Kind of Blue phase. What's the occasion? <div class="Discussion_UserSignature"> I'm a recovering optimist - things could be better. </div>

MeteorWayne · Sep 11, 2007

Holding their breath until they can approve images again has turned them blue <img src="/images/icons/frown.gif" /> <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

MeteorWayne · Sep 11, 2007

One thing that's stood out for me so far is how soft the edges of all the craters are, except for a few along the ridge. It must be a very active micrometeoroid environment. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

jaxtraw · Sep 11, 2007

Many of the smaller craters, especially on the ridge, look (to my amateur eyes) surprisingly deep, to use a bad analogy like pebbles flung into a snowdrift. But the lighting could be creating that effect with those long shadows...

3488 · Sep 11, 2007

Hi all, I'm back (as SDC members log off in droves). Thank you CalliArcale for your answer. I thought the method that generates the raw images was automated. Did not realise a person had to do it. Learn something new every day. BTW, why have you changed from Purple to Blue?? Hope that you are not feeling blue??? jaxtraw's observation does suggest to me, craters that are drilled in on the Voyager Mountains (like those on Hyperion), but those on the 'plains' are not. It does seem consistent with the Voyager Mountains, being made at least in part of loose rubble, but the terrain under the dust is as hard as solid rock (ice at these cryonic temperatures will be). There are also landslides visible on the mountains too (despite the anticipated one fiftieth or 2% surface gravity). The oblique lighting may also make the craters look deeper than they really are, but IMO they are deep in proportion to their width on the Voyager Mountains, but less so on the plains. MeteorWayne makes a fascinating observation, that the craters generally appear to have soft outlines. I assume he area's seen close up, thus far are on the Cassini Regio. Perhaps the mechanism that makes Cassini Regio dark, is still happening?? If we get similar resolution images of the bright trailing hemisphere, will the craters look so soft?? thanks Vogon for your diagram. The mountains closest Cassini do appear to have a flattish top. I still think that the ring theory still holds out. Dunno if this might help, but this is a view of the base of the Voyager Mountains where they actually rise from the 'plain' Base of Voyager Mountains enlargement. Andrew Brown. <div class="Discussion_UserSignature"> "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". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

h2ouniverse · Sep 11, 2007

Hi Andrew and all, Fantastic pictures. I missed the RV (professional travel). The ridge looks very old (anterior to the Great bombardment?), and dead. Does not resemble to a relatively recent capture of a ring by Iapetus. MW, do you think an active process is still possible given the appearent terrain age? Best regards.

3488 · Sep 11, 2007

Hi Joel, I know that I am not MeteorWayne, but IMO, that ridge is a s dead as the proverbial Dodo. It is a fossil of an era long since gone. The collapsed ring theory still holds out, age is not necessarily a barrier, other then impact cratering. Also I think Iapetus is as alive as T-Rex too. IMO, the ice crust is so thick, that any cryovolcanic magmas are trapped in a mantle, if Iapetus even has that. I think we will have to wait for the gravity data, along with any clues from the magnetometers. Iapetus does not appear to be under the influence of tidal heating, & whilst there may be some radiological heating of the core (Iapetus is dense enough for a rocky core containing a little metal maybe), I doubt, that it is anywhere near enough to keep H20 liquid. H20 is in a huge abundance, making up potentially the largest part of the volume, but I suspect that it is frozen solid. Any liquid IMO is likely to be at the Core / Mantle boundary, if there is one. Having said that, Iapetus is not another Rhea. With its huge mountain belt, misshapen globe, bright / dark hemispheres, Iapetus is a completely different & a more interesting creature IMO. Hi Vogon, I have enlarged & sharpened up the Voyager Mountains on the limb of Iapetus, post closest approach. The shape of them appear quite different to the ones that passed underneath Cassini. The do not appear flat topped. What do you think??? Less damaged???? Those closer to Cassini on that same image are certainly flat topped, almost Mesa like. Update here. Andrew Brown. <div class="Discussion_UserSignature"> "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". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

robnissen · Sep 11, 2007

I think I am about to display my ignorance here, but here goes: Is it possible that the heavy cratering on Iapetus is not old? In particular, could the material in Saturn's rings regularly be striking Iapetus to make it so heavily cratered?

h2ouniverse · Sep 11, 2007

Hi all, 1) Indeed on NASA's picture (http://www.nasa.gov/mission_pages/cassini/media/cassini20070911b.html) the craters look both smooth and deep, except one large that seems to have cleared a surface layer above a harder terrain 2) on Andrew's link, the ridge looks very symmetrical, almost shaped only by gravity, like on a rubble pile. To me it looks like Phoebe or Hyperion with more gravity of course, but as if there is a rather thick layer of low density material, on the dark face and making the Voyager ridge. Regards.

Approaching Iapetus - what makes it two-faced?

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