Rev 49 - Aug 9-Sep 14, 2007 - Iapetus I1, The only close flyby of Iapetus Options

[Stu]

Just catching up on the fly-by here, having been at work yesterday afternoon and evening (UK time) and so unable to sit with you all watching the images come in... wow... I hope every "disaster" in the future gives us such stunning pictures of ice-capped mountains, black-sprayed craters and the like...

Looking at these images I can't help thinking that it's a window onto the future, a hint of what it will be like on that amazing day in a century or so when the first pictures reach Earth from the first interstellar probe, and we see truly alien worlds and alien landscapes for the first time...

Looking forward to seeing those mountains now, that will be one of Cassini's greatest successes I think.

Congratulations to everyone involved in this successful mission, and, again, thank you for letting us "out here" see the images so quickly.

[Steve G]

That looks like fresh snow!

Attached thumbnail(s)

 

[alan]

Recent impact of lump of dark material?
(dark ring near right edge)
http://saturn.jpl.nasa.gov/multimedia/imag...3/N00092005.jpg

edit: never mind, I see it on some other images, its a dust spot that was enhanced by the contrast stretch.

[volcanopele]

alan, That's a camera artifact. That's my evil nemesis, the Dust Moat.

[JRehling]

[...]

[ugordan]

That looks like fresh snow!

Holy &%#!"!/%1#"$%/$!!!!

.... picking my jaw off the floor after getting a grip...

Regarding the white-on-black (WOB ?) theory; how exactly does that explain the several fresh craters with excavated bright ejecta? We see brighter patches like that all over the dark terrain, but we don't see dark stuff being excavated similarly. In fact, what struck me most is the sharpness of the dark boundary in predominantly white terrain.

This shot literally reminds me of a Rorschach inkblot.

This has absolutely, positively been the best flyby, EVER! From the point of being able to watch it unfold in real time, having really inside info on the scientific observations and the very results in the end, this flyby will IMHO be one that define what Cassini's mission at Saturn is remembered for. The sheer beauty and grandness of these scenes (still waiting for the mountain flyover sequence!) just have to make some of this into the best picture of the year!

[hubdel11]

can't help mysellf

[akuo]

Excellent flyby, kudos to Cassini team!

I asked earlier what was the height of the mountain ridge, because I've been wondering if some peak on Iapetus could take the position as the highest mountain in the solar system, thus overtaking Olympos Mons. Seeing that the ridge isn't so uniform, I think this might be possible. Could this mountain be a candidate?
http://saturn.jpl.nasa.gov/multimedia/imag...3/W00035183.jpg

[edstrick]

The limited resolution of Hubble data doesn't help, but that central peak in the south-hemisphere <damn near> crater on Vesta...it's so big it's almost a spallation-scar!... might be a candidate.

[ElkGroveDan]

can't help mysellf

That is really useful. Thanks.

[edstrick]

Um...
Does anybody think it would NOT be a good idea to break the nomenclature scheme and name a major basin or other feature on Iapetus after Hermann Rorschach, creator of the InkBlot test?

[ngunn]

mm-hmm sure looks like white on black.
Could a swarm of comets cause such a wierd distribution of evenly bright material? It looks like snow. And the dark areas don't feel icy at all, they look like hammered metal, like a terrrestrial planet.
It's wonderful for us non-scientists to feel the thrill and immediacy of it all; truly awesome. Now, back to the pictures...

Well, up to now we've had some pretty tortured attempts to explain where the dark stuff came from. Now we see white on black and people are still reaching out for an external source - comets . . Enceladus . .
I really don't buy any of that. The source of both has to be the dirty, poorly differentiated bulk material of Iapetus itself, acted on by a continuing process that you could call a 'runaway blackhouse'. Congratulations John Spencer.

[ugordan]

Are these saturnshine shots?
http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=126370
http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=126371
http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=126372
The subtle and diffuse lighting appears to suggest so, but they look almost too good to be saturnshine shots. Then again, these are WAC frames and they require lower exposures, but there's something about the geometry that tells me these can't be saturnshine?

[ngunn]

And now we can see why some of the 'white mountains' appeared to be off the great circle of the ridge:

http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=126368

[ugordan]

Ngunn, are you sure those are Voyager mountains? I'd say that's just part of the ridge further east, still within the dark region. Here's Emily's quick composite of narrow angles covering the actual mountains, note the contrast is MUCH higher there.
Here's the wide-angle context, rotated 90 deg counterclockwise w/respect Emily's swath, north is down.

It would appear they aren't really much of a mountain, rather a strong play of light and dark terrain.