Lake like feature on Titan

[chew_on_this]

From Ciclops:<br /><br />MEDIA RELATIONS OFFICE<br />CASSINI IMAGING CENTRAL LABORATORY FOR OPERATIONS (CICLOPS)<br />SPACE SCIENCE INSTITUTE, BOULDER, COLORADO<br />http://ciclops.org<br />media@ciclops.org<br /><br /><br />Preston Dyches (720) 974-5859<br />Cassini Imaging Central Laboratory for Operations<br />Space Science Institute, Boulder, Colo.<br /><br />Carolina Martinez (818) 354-9382<br />Jet Propulsion Laboratory, Pasadena, Calif.<br /><br />Erica Hupp/Dolores Beasley (202) 358-1237/1753<br />NASA Headquarters, Washington<br /><br />For Immediate Release: June 28, 2005<br /><br /><br />NASA'S CASSINI REVEALS LAKE-LIKE FEATURE ON TITAN<br /><br />Scientists are fascinated by a dark, lake-like feature recently observed on Saturn's moon Titan.<br /><br />NASA's Cassini spacecraft captured a series of images, released today, showing a marking, darker than anything else around it. It is remarkably lake-like, with smooth, shore-like boundaries unlike any seen previously on Titan.<br /><br />"I'd say this is definitely the best candidate we've seen so far for a liquid hydrocarbon lake on Titan," said Dr. Alfred McEwen, imaging team member and a professor at the University of Arizona, Tucson. The putative lake measures 230 kilometers by 70 kilometers (145 miles long by 45 miles) wide, about the size of Lake Ontario, on the U.S. Canadian border.<br /><br />The feature lies in Titan's cloudiest region, which is presumably the most likely site of recent methane rainfall. This, coupled with the shore-like smoothness of the feature's perimeter makes it hard for imaging scientists to resist some speculation about what might be filling the lake, if it indeed is one.<br /><br />Cassini imaging team member Dr. Tony DelGenio of NASA's Goddard Institute for Space Studies in New York, said, "It's possible that some of the storms in this region are strong enough to make methane rain that reaches the surface. Given Tit

 

[gavino]

I took a look at that pic of the possible lakeon Titan, it might just be there! <div class="Discussion_UserSignature"> <p><span style="font-style:italic" class="Apple-style-span">gavinovz</span></p><p> </p> </div>

 

[huey_pilot]

But a lake of what? Liquid methane?

 

[someone_else]

And how do the scientists go about figuring out the composition of said feature? How do they determine if it is, in fact, liquid or solid? This is such an incredible find! I really hope that it is a liquid lake...what an amazing discovery that would be. And in my lifetime, to boot!

 

[dragon04]

Maybe it's an optical illusion, but looking at the "lake" and then the surrounding terrain, it looks more like an oddly shaped volcanic caldera to me. Like what's been seen on Io. <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[chew_on_this]

Could be, then filled with hydrocarbons.

 

[webscientist]

A strong argument in favour of a sea:it's one of the cloudiest areas.I say "sea" because it's a 250 km long dark patch.If it's related to a a cryovolcano as you say,it is a warmer area possibly made up of a mixture of dust,methane, ethane or even ammonia ( as postulated Jonathan Lunine).<br />I'm relieved to see that clouds are not so scarce on Titan!<br />But the debate is still there over the origin of methane on Titan:clouds or volcanoes?

 

[chew_on_this]

Well, if that's the case, then we all may as well be monkeys...

 

[yurkin]

It looks like a duck. The question is, does it quack like one?

 

[vogon13]

Just curious, is the size of the 'lake' comparable to the landing error ellipse for Huygens ?<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[chew_on_this]

I would think the landing ellipse is larger. The lake is 145 miles x 45 miles.

 

[volcanopele2]

True, we need more evidence before we can definitively state this IS a lake. Our exploration of Titan is a bit like groping in the dark but that doesn't mean we should just ignore interesting looking features. Certainly, this is nothing more than a hypothesis that needs to be tested, through future observations by VIMS and RADAR, just like the volcano from earlier this month.

 

[mrmorris]

<font color="yellow">"Our exploration of Titan is a bit like groping in the dark..."</font><br /><br />No -- groping in the dark is much more squishy, and occasionally slippery. But perhaps that line of thought should be continued in the 'Human Biology' forum... <img src="/images/icons/smile.gif" />

 

[volcanopele2]

You do realize that methane and ethane are liquids at Titan surface conditions (93.8K and 1.47 bar)?

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>And how do the scientists go about figuring out the composition of said feature? How do they determine if it is, in fact, liquid or solid?<p><hr /></p></p></blockquote><br /><br />One way is to try to image it again at a more favorable phase angle for glinting. If you watch Shuttle footage of the Earth taken during a mission, you may at times notice a bright light glinting off of the water below, which disappears when it should cross land. This is of course sunlight. If they can see that sort of an affect in a manner consistent with sunlight reflecting off of liquid, then they'll have a very good case for it. Of course, even if it is liquid, that doesn't answer the question of where it came from.<br /><br />And liquid it certainly could be. What it reminds me of most is the volcanic calderas on Io. Those are effectively lakes of sulfur, fed by volcanic vents. There are lakes of lava on Kileaua, the world's most active volcano, which has been erupting continuously for two decades. These could be the result of a similar process, although given the density of Titan, there is probably a high water content. In other words, this could possibly be the caldera of an active cryovolcano.<br /><br />Or it could be something else. If it's not liquid, it would likely be an albedo feature -- in other words, just a dark patch. But it's so dramatically dark that it begs the question of why it's so dark, and there are lots of possibilities for that as well. <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>

 

[mrmorris]

<font color="yellow">"One way is to try to image it again at a more favorable phase angle for glinting. "</font><br /><br />That's going to need to be a <b>really</b> favorable phase angle considering Titan is at 9+ AU... with an atmosphere thicker than Earth's and constant cloud cover... to be able to get a glint. <img src="/images/icons/smile.gif" />

 

[chew_on_this]

I think Cassini will be doing the imaging...not from Earth.

 

[mrmorris]

Your point being?

 

[aaron38]

The imaging of the glint would be done at the infared wavelength where Titan's atmosphere is transparent.<br /><br />Casini observed sunlight glinting off the rings, it should be able to see something.<br />

 

[bobvanx]

The glint on the rings was stunning, and in visible light. I don't have any idea if the very specific wavelength of infrared that gets through Titan's clouds would reflect off a liquid surface. Let's see, I know that UV reflects off water really well, and long infrared penetrates water to a pretty good depth...<br /><br /><br />Ah. I know how they can do it. Radar reflections. Radar reflects off a liquid surface quite differently than a non-liquid surface. I don't know if the radar's resolution is up to the challenge, but if this feature is large enough, I'd wager they could manufacture a glint with radar.

 

[mrmorris]

<font color="yellow">"I'd wager they could manufacture a glint with radar. "</font><br /><br />How? The 'glint' is the radiation from the sun being captured at a specific angle such that you get a peak reflection. Radar isn't generating images from radio waves emitted by the sun, but rather by the craft itself. Ergo even if you could get glints from radar -- you wouldn't be at the right angle to get a glint. I suppose you might be able to do it with two spacecraft... maybe.

 

[CalliArcale]

You can get specular reflections (glints) in infrared or in radio. In fact, Areceibo detected a specular reflection off of Titan a few years ago, although given the distance it's hard to know what to make of that. In that case, Areceibo was detecting the reflection of its own radar beam off of Titan. I'm not sure whether the Cassini team is planning to search for glints in infrared or radar, but those are basically their only options. If they're looking for infrared glints, I suspect they will need to do some pretty serious image enhancement to detect them; they probably won't be all that bright. But if they know where to look, they should be able to tell whether or not there are any. <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>

 

[chew_on_this]

A glint doesn't necessarily need to come from a flat surface at an obtuse angle. The spacecraft could recieve feedback from a rippled surface without an overshot angle.

 

[volcanopele2]

Huygens directly measured the surface temperatures and found it to be 93.6K (-179.5 C). The melting point of methane is at -183 C (maybe you got the temperatures switched?) and the ntiriles in the atmosphere further act as an antifreeze, reducing the melting point. So methane is liquid at Titan's surface. Ethane has very similar values. But the surface temperature globally is certainly with 1 or 2 K of 94 K based on models of the lower atmosphere at the surface temperature Huygens measured.

 

[chew_on_this]

Steve also ignores the potential interior tidal heating that could also cause outflows.