Unveiling Titan

[robnissen]

So, was it just blind luck that the landing ellipse appears to be in a very interesting part of Titan, or was there something from earth/Hubble/Voyager that identified the landing ellipse as being an interesting spot? My belief was that the landing ellipse was chosen for engineering, not scientific reasons, but I could be completely wrong.

 

[remcook]

who knows what's interesting, if we don't even know what the dark and light stuff is? And there was much less information when they chose the landing site. So, yes most of it is based on engineering I would think.

 

[volcanopele2]

Actually, the Huygens landing ellipse is farther to the west, as illustrated below. Still a good mix of dark terrain and linearly trending 'islands' and blocks.

 

[centsworth_II]

<font color="yellow">"My belief was that the landing ellipse was chosen for engineering, not scientific reasons..."</font><br /><br />Something to that effect was stated at a Cassini briefing I saw. At any rate, that particular light-colored "island" was unknown until Cassini's recent observations. <br /><br />Its strange to be talking about interesting parts of Titan, as if any part could be uninteresting! <div class="Discussion_UserSignature"> </div>

 

[centsworth_II]

OK, looks like we'll be looking down on a light-colored peninsula, or archepelago rather than an island.<img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> </div>

 

[chew_on_this]

Here we go again!

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>Peninsulas and archipelagos are features found on earth in oceanic regions.<p><hr /></p></p></blockquote><br /><br />Correct, but for purposes of discussion the terms can be useful in other contexts. For instance, one can speak of a region jutting out into another region as a "peninsula" (with the word in quotes) because it is very evocative and will immediately get the other people to identify the feature you're talking about. Human language does have some serious limitations when you're trying to describe an unknown surface without prejudicing the conversation. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"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."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[volcanopele2]

Take it down a notch there. Yes, those terms refer to places on earth in oceanic regions. However, given our general lack of knowledge of what is happening on the ground on Titan, we need some terms that at least are descriptive of their shape and albedo relationships (since we can't see topography). So islands and archipelagos and peninsulas are perfectly fine words to use in this time of uncertainty as long as the speaker (or poster) is aware that they in no way mean that there must be liquids (in the form of ethane or ethane/methane mixture which CAN be liquid at -180C) for them to exist. Personally, many of the features on the anti-Saturnian hemisphere (seen above) do not need liquids at present though the sub-Saturnian hemisphere (seen in T0) maybe a different story.

 

[alexblackwell]

A Conversation With John Zarnecki, Principal Investigator, Huygens Science Surface Package<br />On the Inspiration of the Sixties, the Romanticism of Exploration, and the Thrill of Diving into Titan<br />Interview by A.J.S. Rayl<br />The Planetary Society<br />November 29, 2004

 

[alexblackwell]

<i>Peninsulas and archipelagos are features found on earth in oceanic regions. There are NO oceans on the moons of Saturn. It's all frozen waste. At MINUS 180 C. <br /><br />Therefore, there are no peninsulas, archipelagos, islands, reefs, atolls, or anthing else of that sort. Come back to ground.</i><br /><br />Don't you ever get tired standing on your soapbox, stevehw33? Next thing you know, you'll be griping to biologists for using the term "Isles of Langerhans."

 

[centsworth_II]

stevehw33 and chew on this:<br /><br />Lighten up guys!<br /><br />We don't even know the physical nature of the light and dark areas of Titan. Liquid, solid, fluff, mush... who knows? I am certainly not implying Islands and peninsulas of land, with sandy beaches, lapped by foam-tipped waves. I'm merely referring to relative shapes. i.e. An "island" or "peninsula" of light in a "sea" of dark -- without any implications reguarding the composition of the light or dark areas!<br /><br />Sheesh! Lighten up! Oh, I said that. <div class="Discussion_UserSignature"> </div>

 

[chew_on_this]

I agree wholeheartedly. It's just the soapbox comes out if any liquid reference is made, even though it's possible and has been postulated by scientists with far more credibility than a rant in a chat room.

 

[volcanopele2]

Not really, no. It doesn't avoid confusion. Everything on Titan is a generic "feature" until we learn more about what they actually are. Yes, it is still somewhat confusing, but at least when a specific feature is mentioned, there can still be hope they we are all on the same page of what feature we are talking about.<br /><br />Though what these features need are proper names. Sure, we would be stuck with facula, macula, and regio for a while, but there's nothing wrong with that.

 

[alexblackwell]

<i>Let's just call those findings on the Jovian moons, "features", shall we? We do not call such findings on the moon, archipelagos or peninsulas. They are called features of the lunar landscape.</i><br /><br />Yeah, I guess we better re-name Mare Tranquilitatis, Oceanus Procellarum, etc. while we're at it. Sheesh.

 

[centsworth_II]

stevehw33,<br /><br />From the Merriam-Webster online dictonary's definition for "island":<br /><font color="yellow">"2. something resembling an island especially in its isolated or surrounded position..."</font><br /><br />Rather than trying to restrict others' use of the language, you should try to expand your own. <div class="Discussion_UserSignature"> </div>

 

[chew_on_this]

Steve says: "The usual term is 'surface features'. That's clear, precise and avoids the false impressions of terrestrial environs, which clearly do NOT and Cannot exist on the Jovian type moons." <br /><br />"We do not know of liquids, yet on the moons."<br /><br />Huh? Now I'm really confused... I hope no impressionable minds try to make sense of this drivle.

 

[centsworth_II]

Steve says: "The usual term is 'surface features'. That's clear, precise and avoids the false impressions of terrestrial environs, which clearly do NOT and Cannot exist on the Jovian type moons." <br /><br />Well, 'surface features' is about as <b>imprecise</b> as you can get! You still have to describe the features. And 'island' is a perfectly appropriate description for one relatively small area surrounded by a larger area of different characteristics. <br /> <br /><br />"We do not know of liquids, yet on the moons." --shw33<br /><br />Ah! The curse of the missplaced comma. We've all been there!<img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> </div>

 

[titanian]

VIMS and radar data reveal some differences in brightness on the surface of Titan.But a scientist from the Imaging Team warned that the variations of brightness between large areas might not be so significant.Does anyone have an idea about the mean albedo in the "bright" areas and in the "dark" areas?<br />I assume that the hypothetical liquid would rather be in the dark areas (since the albedo is logically weaker).<br />If you say less than ten percent in the dark areas, one can conclude that the physical properties of the surface are similar to the physical properties of water oceans ( sorry for the redundancy) on Earth ( same albedo).If it's more than ten percent, one can ask what could be the albedo of an ocean consisting of mixtures of hydrocarbon compounds.If you say more than 50 percent,one can postulate a Europa like surface.I bet that Stevehw33 will bet on this hypothesis.

 

[alexblackwell]

A new paper in press with <i>Icarus</i>:<br /><br /><b>Numerical calculations of the longevity of impact oases on Titan</b><br /><i>Icarus</i>, In Press, Corrected Proof, Available online 30 November 2004<br />David P. O'Brien, Ralph D. Lorenz and Jonathan I. Lunine<br />Abstract

 

[volcanopele2]

VIMS revealed an order of magnitude difference between the albedo of the dark terrain and that of the bright terrain. ISS, because the atmosphere reduces the top of atmosphere contrast, doesn't as much difference, but again this is likely an effect of the atmosphere and not some property of the surface.

 

[alexblackwell]

PIA06995: Follow the Arrow<br />December 1, 2004

 

[centsworth_II]

<font color="yellow">"...avalanche scars..."</font><br /><br />The surface of Titan, at least where the radar images were taken, was found to be fairly flat. Not much chance of large avalanches. I guess current theories for a lot of these type of surface features involve either flowing liquids (or mush or goo) or wind blown deposition or removal of surface material. <div class="Discussion_UserSignature"> </div>

 

[fangsheath]

We should be very careful about extrapolating large areas of Titan from a very small sample. As I understand it, the elevation data come from only a single transect about 400 km long. Very skewed impressions of the surface of Mars were given by the early Mariner probes, based on considerably larger samples.<br />

 

[volcanopele2]

And the transect did not cross a bright/dark boundary, AFAIK. So it is still up in the air on whether there is a topographic boundary associated with the albedo boundary. If there isn't, then wind-blown hardended aerosols certainly look a lot more likely. If there is, then ethane/methane liquid or cryolava could be a likely carver of the terrain along with tectonism.

 

[centsworth_II]

<font color="yellow">"We should be very careful about extrapolating large areas of Titan from a very small sample."</font><br /><br />Of course! The amazing thing is how much there is to ponder in just that small (1%) slice of Titan covered by the radar in the last fly-by. Without knowing what to expect, I think this small sample has shown us that we can expect many curious, amazing sights as the study of Titan continues.<br /><br />Concerning the "arrow", this specific feature is located in the same radar-imaged swath that was found to be relatively smooth. So any speculation concerning its formation should take that smoothness into account. Maybe not an avalanche, but what about mass slump? <div class="Discussion_UserSignature"> </div>