[X] My Assistant

[ngunn]

Mountains on Titan - news via jupiter list:
http://tech.groups.yahoo.com/group/jupiter_list/message/7565
Edit: Shouldn't be in T21 thread - don't know how to move it though.

[volcanopele]

Massive Mountain Range Imaged on Saturn's Moon Titan
http://saturn.jpl.nasa.gov/news/press-rele....cfm?newsID=709

I'm not so sure I agree with their conclusion, but they seem to think that based on the appearance of the dark "stuff" to the east of the bright streaks at different wavelengths, that that dark "stuff" is topographic shading and that the bright streaks are mountain chains. I am not sure I agree with that statement. I can't go into detail why, but I think bright streaks are some kind of "stain" on the surface, not topographic.

The more interesting news is the statement:

The composition of dunes that run across much of Titan is also much clearer. "The dunes seem to consist of sand grains made of organics, built on water-ice bedrock, and there may also be some snow and bright deposits," Brown said.

VIMS was able to resolve the dunes and able to see the compositional differences between the dunes and the inter-dune regions.

[alan]

I've been looking forward to seeing something like this:
Combined IR and radar views

volcanopele: what direction does the wind blow on the Titan's surface?

[ugordan]

what direction does the wind blow on the Titan's surface?

Westward.

[Guest_AlexBlackwell_*]

Westward.

And I was going to say "leeward."

[volcanopele]

volcanopele: what direction does the wind blow on the Titan's surface?

West to east

[ngunn]

I'm not so sure I agree with their conclusion, but they seem to think that based on the appearance of the dark "stuff" to the east of the bright streaks at different wavelengths, that that dark "stuff" is topographic shading and that the bright streaks are mountain chains. I am not sure I agree with that statement. I can't go into detail why, but I think bright streaks are some kind of "stain" on the surface, not topographic.

Thanks for posting the proper link.
Are you questioning the whole mountain range idea or just a more subtle aspect of their interpretation?
Does the 3D appearance of the 'mountain' image arise from processing based on an assumption about the topography or is it intrinsic to the data?

[volcanopele]

They could be mountain ranges, but I question that they are seeing topographic shading, which underpins their mountain interpretation. I think the "3D" appearance arises from the pattern of bright-dark material in that region that makes it look like some of the dark material is actually topographic shading.

Though this image, http://saturn.jpl.nasa.gov/multimedia/imag...fm?imageID=2381, is really good for having been taken from 12 billion km away

[ngunn]

Though this image, http://saturn.jpl.nasa.gov/multimedia/imag...fm?imageID=2381, is really good for having been taken from 12 billion km away

It is, isn't it! Looks a bit lke that thing on Iapetus.

[helvick]

....really good for having been taken from 12 billion km away

Very clever of them to put such a good instrument on Voyager 1

[JTN]

VIMS was able to resolve the dunes and able to see the compositional differences between the dunes and the inter-dune regions.

There's an image supporting this (side-by-side comparison of radar and VIMS) that appears on the VIMS site (caption is near the bottom), but not on the JPL site, for some reason. (The same region with VIMS overlaying radar is here, but the caption doesn't mention the dunes.)

[Jason W Barnes]

I guess I shouldn't be surprised to find that this group picked up on the newly released VIMS T20 images so quickly!

Originally the RADAR/VIMS with the dunes there was supposed to be an animated .gif blink, I thought, but maybe we were going overboard with the blinks, so they just released the straight VIMS over RADAR comparison. I kind of like the blink version better, as it seems to be the best way to intercompare the two. Did you see the sinuous red streak near the RADAR circular feature in the lower left? Better than 400m resolution -- we're getting down toward the scale of flows on, say, Mauna Loa.

[Jason W Barnes]

Aha -- you have to go into the 'full-res' part to get the blinks. Here are direct links to them:

T20 outbound noodle and mountains over T17 global

Cryoflow and dunes

[ngunn]

Thanks Jason B. Can you (or anyone) answer the question I put (not very clearly) to the other Jason? it's about the 'mountains' image. Has there been any reprojection of the image following 'draping' over inferred topography?

I suspect the answer is 'No' but just want to be sure.

[Matt]

I hope this is correct about the taller mountains, because I was always very fond of the orographic interpretation regarding those mid-southern latitude clouds.

They sound pretty conclusive about it.