[X] My Assistant

[Stu]

With an hour or so to kill before heading out to work I thought I'd have a play about with the images of the "lakes". Having read that it might be possible to enhance these or future images to bring out more details - maybe even waves - I just started playing about with contrast and brightness, seeing what popped out... and just doing that shows detail and some features within the "lakes" which I'm interested in people's comments on.

Titan lake

Now, before anyone tells me off for my "playing about" and points out, rightly, that you can't just take these raw images and pull info out without a LOT of work, please bear in mind I KNOW all that, okay? I'm no Nix or Nirgal or Horton, and I'm not suggesting this means anything, I'm just curious what I might have seen. I know the features might just be imaging artefacts, but... oh, just take a look and see what you think. I'm just pushing the ball down the hill here, not making any claims. I would be interested to hear what others think tho.

Sticking my neck out here, to me it looks like the "drainage channel" on the lower right hand side actually continues into the "lake" for quite a way, maybe even flowing beneath an "island" of some sort. Other things look like they're in there too, but I'm just wondering if the "lake" is actually very shallow and we can see channels on its floor...

Features?

...but heck, what do I know...

[ustrax]

Well...It looks like an abyss to me...



Edited: Now, "seriously", it's incredible the detail on the 'lake' shoreline...it looks like coral reefs...

Maybe Titan will be the one...

[climber]

Sticking my neck out here, to me it looks like the "drainage channel" on the lower right hand side actually continues into the "lake" for quite a way, maybe even flowing beneath an "island" of some sort. Other things look like they're in there too, but I'm just wondering if the "lake" is actually very shallow and we can see channels on its floor...

Stu,
I understand what you mean and I like this. Remember when you show us those "gullys" in VC? .
I see what you see too but, well, I'd like to hear about the specialists. I have also a general question about the images (easily visible on your's) : what are the parrallel "stripes" that show pretty well over the lake?

[um3k]

Here's my version of the image. The vertical stripes, which are imaging artifacts, have been removed by using a Fourier transform.

[Phil Stooke]

I agree with stu - these are not artifacts. Check out this version too:



This can't be a body of liquid unless the radar can penetrate liquid hydrocarbons enough to give weak reflections off the bottom.

Phil

[Stu]

VERY nice Um! Thanks for that. Love the detail visible on the shoreline...

I'm thinking now these interior featueres might be evidence that these lakes are transient features... they fill up, shrink back, leaving just channels on their floors to transport the liquid down to the lowest points in their centres, then they fill up again, the channels get re-covered and voila, we have a lake again...

Off to work now so I'll look forward to much more expert input than my own when I get home tonight!

[JRehling]

I'd like to see a polar cartographic projection of this data. I wonder if we're just seeing patchy lakes at 80N while things get wetter on towards the actual pole. Roughly speaking, if you stacked three of these strips one atop another, the top of the third would be at the pole.

Remember that we're looking at a place that hasn't seen daylight in about a decade. Also note that we've known of rains at the summer pole, but we're looking at the winter pole. Is there a wet season/dry season? Or two wet seasons at each pole? Or one continuous wet season? This may be the wettest time of year here or it may be the dryest.

I don't think we can yet rule out that there could be a winter ice cap at the pole... this isn't winter, BTW, and it won't be winter solstice at the other pole until 2017. If the temperature bottoms out after that, we won't know it til the next mission: Cassini is probably not going to live long enough to see solstice unless its operations are budgeted very, very carefully to keep it pretty much dormant and conserving propellant until a "solstice" mission could take place.

[Guest_Sunspot_*]

I always assumed the black kidney bean shaped features were the lakes rather than the feature referred to in this thread?

[MarcF]

The whole region looks like a big methane marsh with more or less deep ponds (if of course liquid is indeed present and if this liquid is methane).
Do we know how deep the radar can penetrate throught liquid methane (or any other liquid) in order to evaluate the possible minimal (or maximal) depths of the putative ponds ?

[Guest_paulanderson_*]

This can't be a body of liquid unless the radar can penetrate liquid hydrocarbons enough to give weak reflections off the bottom.

Phil

The Space.com (AP) article mentioned several of the lakes being dried up, but others apparently containing liquid:

Researchers counted about a dozen lakes six to 62 miles wide. Some, which appeared as dark patches in radar images, were connected by channels, while others had tributaries flowing into them. Several were dried up, but the ones that contained liquid were most likely a mix of methane and ethane. "It was a real potpourri," said Cassini scientist Jonathan Lunine of the University of Arizona.

http://www.space.com/scienceastronomy/ap_0...itan_lakes.html

From the New Scientist article:

Earlier images from Titan also showed dark patches that were considered possible lakes, but they were less dark. "In this case it is much clearer. The contrast is so great that there are few doubts that the surface is a liquid one," says Enrico Flamini of the Italian Space Agency in Rome, a member of the radar instrument team. The new evidence is quite strong, but the case is not quite closed. These patches could still just be areas of soot, or dry lake beds. Imaging the area again could show if the lakes grow or shrink – and possibly even reveal waves.

http://www.newscientistspace.com/article/d...-after-all.html

Perhaps these lakes are in various stages of evaporation, some dried up for now and some still filled with liquid?

[elakdawalla]

Here's an example of a dried-up lake. I was trying to figure out exactly what kinds of features Rosaly Lopes and Karl Mitchell were talking about when they were talking about possible calderas. I sent this doodle to Karl, asking "I'm wondering if there are features in the press-released chunks that look like collapse features that _don't_ have liquid gathered in them. For example, if you look at the top swath chunk, at the west end, I think I see something that looks like a topographic depression that's not filled -- am I interpreting the sense of illumination correctly? (I attach a quick and dirty map to show what/where I'm talking about)


Karl replied, "We saw that depression too and discussed it for a while. A popular theory is that the lake was larger at some time in the past, and that the depression you mention evaporated (because it was shallower) or drained into the remaining body. I keep thinking of the Aral Sea as a possible analogue. The dichotomy between the pale and dark depressions seems to support the "dark = liquid" hypothesis. The "calderas" I'm looking at are much small and steeper-rimmed...." The rest of what he had to say I put in my article.

And yes, Sunspot, the telltale lakes are the ones that look kidney shaped; they seem to be in a variety of states of wet / drying / dried up, at least that's what the team is saying. If they are, in fact, lakes.

--Emily

[Guest_paulanderson_*]

Very good, thanks for this, Emily. And excellent article, too, I had already blogged it yesterday.

[David]

My impression now is that Titan has some but not a lot of surface liquid, but that there is evidence that Titan was wetter in the past and had more widespread surface liquids.

If this is so, it raises the question, when was the wetter period, what is the timeline of the drying-up, is the process linear or cyclic, and what caused the current drought? I realize that most of these questions are not currently answerable, but I wonder if it's at least possible to answer within several orders of magnitude: is the time one has to go back to find wetter conditions on Titan closer to 5 years or 5 million years?

[Phil Stooke]

This version of the new image is a bit easier to interpret in darker areas.

Phil

[Guest_AlexBlackwell_*]

This version of the new image is a bit easier to interpret in darker areas.

Nice work, Phil.