Surface of Titan Sea is mirror smooth, scientists find

Mar 20, 2014
This false-color image of the surface of Titan was made using radar measurements made by NASA's Cassini spacecraft. The spacecraft revealed that the surface of Ligeia Mare, Titan's second largest lake, is unusually still, most likely due to a lack of winds at the time of observation. Credit: Howard Zebker

New radar measurements of an enormous sea on Titan offer insights into the weather patterns and landscape composition of the Saturnian moon. The measurements, made in 2013 by NASA's Cassini spacecraft, reveal that the surface of Ligeia Mare, Titan's second largest sea, possesses a mirror-like smoothness, possibly due to a lack of winds.

"If you could look out on this , it would be really still. It would just be a totally glassy surface," said Howard Zebker, professor of geophysics and of electrical engineering at Stanford who is the lead author of a new study detailing the research.

The findings, recently published online in Geophysical Research Letters, also indicate that the solid terrain surrounding the sea is likely made of solid organic materials and not frozen water.

Saturn's second largest moon, Titan has a dense, planet-like atmosphere and large seas made of methane and ethane. Measuring roughly 260 miles (420 km) by 217 miles (350 km), Ligeia Mare is larger than Lake Superior on Earth. "Titan is the best analog that we have in the solar system to a body like the Earth because it is the only other body that we know of that has a complex cycle of solid, liquid, and gas constituents," Zebker said.

Titan's thick cloud cover makes it difficult for Cassini to obtain clear optical images of its surface, so scientists must rely on radar, which can see through the clouds, instead of a camera.

To paint a radar picture of Ligeia Mare, Cassini bounced radio waves off the sea's surface and then analyzed the echo. The strength of the reflected signal indicated how much wave action was happening on the sea. To understand why, Zebker said, imagine sunlight reflecting off of a lake on Earth. "If the lake were really flat, it would act as a perfect mirror and you would have an extremely bright image of the sun," he said. "But if you ruffle up the surface of the sea, the light gets scattered in a lot of directions, and the reflection would be much dimmer. We did the same thing with radar on Titan."

The suggest the surface of Ligeia Mare is eerily still. "Cassini's radar sensitivity in this experiment is one millimeter, so that means if there are waves on Ligeia Mare, they're smaller than one millimeter. That's really, really smooth," Zebker said.

One possible explanation for the sea's calmness is that no winds happened to be blowing across that region of the moon when Cassini made its flyby. Another possibility is that a thin layer of some material is suppressing wave action. "For example, on Earth, if you put oil on top of a sea, you suppress a lot of small waves," Zebker said.

Cassini also measured microwave radiation emitted by the materials that make up Titan's surface. By analyzing those measurements, and accounting for factors such as temperature and pressure, Zebker's team confirmed previous findings that the terrain around Ligeia Mare is composed of solid organic material, likely the same methane and ethane that make up the sea. "Like water on Earth, methane on Titan can exists as a solid, a liquid, and a gas all at once," Zebker said.

Titan's similarities to Earth make it a good model for our own planet's early evolution, Zebker said. "Titan is different in the details from Earth, but because there is global circulation happening, the big picture is the same," he added. "Seeing something in two very different environments could help reveal the overall guiding principles for the evolution of planetary bodies, and help explain why Earth developed life and Titan didn't."

Explore further: Cassini sheds light on Titan's second largest lake, Ligeia Mare

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HannesAlfven
1 / 5 (7) Mar 20, 2014
Note the alternative possibility -- which Wal Thornhill has advocated -- is that this is not a fluid at all.

From http://www.thunde...itan.htm

Aug 15, 2006
Titan Update—Our Prediction Stands

Recent weeks have seen growing confidence by NASA scientists that they have observed methane "lakes" on Saturn's moon Titan. But we stand by our prediction that no methane lakes will be found.

--

It probably looks like a mirror because, if I'm reading Wal right, it's basically melted glass.
Whydening Gyre
3.6 / 5 (5) Mar 20, 2014
glass is considered a fluid, isn't it?
barakn
4.7 / 5 (13) Mar 20, 2014
You're not right, and neither is Wal. Yet another failed prediction from EU. First, part of the shoreline of Ontario Lacus was observed to retreat several km over a short period of time, behavior that staggers the imagination when applied to a glass or the surface of an electro-machined solid, but one that makes perfect sense if it's a liquid. http://www.scienc...11000546

The observations of Ligeia Mare itself were able to resolve a bottom 170 m below the surface, which wouldn't be possible unless the substance between the top and the bottom was pure liquid methane. http://spaceref.c...tan.html

And then of course there are the recent observations of what might be waves on some lakes: http://www.hou.us...1947.pdf

But keep on posting links like http://www.thunde...itan.htm , they are quite entertaining.
Q-Star
4.9 / 5 (8) Mar 20, 2014
glass is considered a fluid, isn't it?


I expect that someone will be along soon to tell us it is plasma.
Whydening Gyre
4.3 / 5 (6) Mar 20, 2014
glass is considered a fluid, isn't it?


I expect that someone will be along soon to tell us it is plasma.

Managed by electricity, no doubt....
Tim Thompson
4.5 / 5 (11) Mar 21, 2014
glass is considered a fluid, isn't it?

Glass is not properly considered a fluid, it is an amorphous solid. This should be fairly obvious, since we have ancient Egyptian glass artifacts thousands of years old that show no sign of flowing in the least bit.
http://math.ucr.e...ass.html
Sinister1812
5 / 5 (4) Mar 21, 2014
Any chance there could be life in those lakes? We should a submersible vehicle there, a rover that transforms into a boat or a submarine.
barakn
4.2 / 5 (5) Mar 21, 2014
Interesting link, Tim. That mention of the second order transition reminds me of Prince Rupert's drop http://en.wikiped...27s_Drop , where the different states of glass within the same chunk can lead to explosive results.
Whydening Gyre
5 / 5 (5) Mar 22, 2014
glass is considered a fluid, isn't it?

Glass is not properly considered a fluid, it is an amorphous solid. This should be fairly obvious, since we have ancient Egyptian glass artifacts thousands of years old that show no sign of flowing in the least bit.

Thanks, Tim. Wasn't aware of that. I guess the European generations of glass makers should have paid closer attention in the Egyptian glassmaking class...:-)
peter_beaumont
5 / 5 (4) Mar 22, 2014
The article says Titan is Saturn's second largest moon, but clearly meant the Solar System's second largest.
HannesAlfven
1 / 5 (5) Mar 22, 2014
Re: "The observations of Ligeia Mare itself were able to resolve a bottom 170 m below the surface, which wouldn't be possible unless the substance between the top and the bottom was pure liquid methane."

Actually, the article you point to qualifies the technique as a "creative application", so why are you speaking as though there is no uncertainty? ...

"A creative application of a method previously used to analyze data at Mars also revealed that Ligeia Mare is about 560 feet (170 meters) deep. This is the first time scientists have been able to plumb the bottom of a lake or sea on Titan. This was possible partly because the liquid turned out to be very pure, allowing the radar signal to pass through it easily."

Also, the researchers are not considering Wal's theory in their inferences, so what is the point of suggesting that it can be ruled out? Isn't that sloppy science/reasoning?
HannesAlfven
1 / 5 (6) Mar 22, 2014
Re: "You're not right, and neither is Wal. Yet another failed prediction from EU. First, part of the shoreline of Ontario Lacus was observed to retreat several km over a short period of time, behavior that staggers the imagination when applied to a glass or the surface of an electro-machined solid, but one that makes perfect sense if it's a liquid."

It actually only staggers the imagination if you have been taught to believe the worldview that electricity in space can only be a byproduct of other more fundamental forces. It's completely unsurprising if you permit the cosmic plasmas to be modeled as laboratory plasmas.

You will lose this debate. The evidence for electrical machining throughout our solar system is much stronger than your confined reading selection permits you to believe.

Debates like this are easier to call when one of the two sides tries so hard to ignore the other side's claims. We listen to you guys every single day. You might want to think about that.
HannesAlfven
1 / 5 (6) Mar 22, 2014
A person need only do a Google Image search on "crater chains", and inspect the imagery to observe that bodies in space do indeed electrically discharge. People who look at those images and refuse to consider electrical discharge are simply trapped by prior belief.

This sort of obstinance costs taxpayers enormous sums of money. The Titan Saturn System Mission (TSSM) -- which includes plans for a lander to splash into these hypothetical lakes -- will cost taxpayers $2.5 billion in total, and won't arrive until 2029.

That's an extraordinary investment of resources, given that there exists debate that these lakes are actually real. I think NASA underestimates the risk associated with this mission. There will be consequences to getting this wrong which could harm the public's perception of the organization.

Also, there is an implicit assumption that the public will not be better informed on plasmas over the course of 14 years. This mission sets NASA up for a dramatic failure.
TheGhostofOtto1923
1 / 5 (1) Mar 22, 2014
Thanks, Tim. Wasn't aware of that.
And you still aren't.
glass is considered a fluid, isn't it?

Glass is not properly considered a fluid, it is an amorphous solid. This should be fairly obvious, since we have ancient Egyptian glass artifacts thousands of years old that show no sign of flowing in the least bit.
http://math.ucr.e...ass.html
Sorry Tim but you did not read your source to its conclusion.

"There is no clear answer to the question "Is glass solid or liquid?". In terms of molecular dynamics and thermodynamics it is possible to justify various different views that it is a highly viscous liquid, an amorphous solid, or simply that glass is another state of matter that is neither liquid nor solid. The difference is semantic."
Whydening Gyre
not rated yet Mar 22, 2014
A person need only do a Google Image search on "crater chains", and inspect the imagery to observe that bodies in space do indeed electrically discharge. People who look at those images and refuse to consider electrical discharge are simply trapped by prior belief.

Fine, they discharge... But what causes the discharge in the first place? It's because there are bodies to actually discharge electricity. Matter interaction creates the discharge. Call it a "friction" dissapation, if you want....

barakn
4.2 / 5 (5) Mar 23, 2014
Actually, the article you point to qualifies the technique as a "creative application", so why are you speaking as though there is no uncertainty? ...
What exactly about the phrase "creative application" suggests uncertainty or doubt? They applied an improved algorithm to the radar data. But let's entertain your little fallacy. Titan's rocks are made of water ice. Electromachining of this surface would lead to a lava... of water. A "glass" that cooled from this lava would be .... water ice. You're implying that Ku-band radar was able to penetrate 170 m through ice to see an ice-ice interface. Ice absorbs Ku band radar more than liquid methane does because it has a higher dielectric constant (about twice as high), making it much harder to see reflections from below the surface of ice than methane. An ice-ice interface would be far less reflecting than a water ice-liquid methane interface. An ice-ice interface at 170 m depth would simply not be visible.
HannesAlfven
1 / 5 (4) Mar 26, 2014
@barakn

See http://www.newsci...67dz89ho

"Ideas about the nature of Saturn's moon Titan are going through a total revolution as a result of new observations from the Cassini space probe ...

close-ups of the surface completely rule out such widespread liquid bodies, say scientists in the Cassini team ...

There had been hope that these bodies of liquid might harbour early stages in the development of biological molecules, and perhaps even simple forms of life. All that has changed, according to planetary scientist Robert Nelson of NASA-JPL. "That paradigm has been shaken to its foundations," ...

the new close-ups, while they only cover a portion of the surface, have completely ruled this out and make it highly unlikely that there is any liquid on the surface at all ...

"There is no evidence of oceans," says Carolyn Porco, Cassini imaging team leader ..."
barakn
4 / 5 (4) Mar 26, 2014
Yes, there are no oceans. There are lakes. So how does trotting out a 10 year old article help your case? Heck, if you linked to a paper written before 1655 you could prove that Titan itself doesn't exist. But no... that's not how it works. Your article came out in 2004, a result of the initial Titan observations being mostly focused on the equatorial regions, especially the landing area of the Huygens probe. Hints of lakes came in observations from 2005, and 2006 observations were the clincher. Also note that the sentence
the new close-ups, while they only cover a portion of the surface, have completely ruled this out and make it highly unlikely that there is any liquid on the surface at all ...
was not a quote from a scientist but written by one of the hyperbole-prone Newscientist staffers.
barakn
4 / 5 (4) Mar 26, 2014
It is no great surprise that you cherry-picked only statements that seem to support your untenable stance. But the very next paragraph reads:
But project manager Dennis Matson cautions that "we've only seen part of Titan". While extensive liquid bodies are ruled out, it is still possible there may be some much smaller bodies. Perhaps more likely, he suggests, is a kind of slushy ice surface.

Why did you fail to mention this? Did it not fit into your paradigm?
HannesAlfven
1 / 5 (4) Mar 26, 2014
Well, yes, it is after all what they most WANT to find, in order to fit into their narrative that there is life elsewhere in the universe. But, you seem to not understand that this narrative is not emergent. It follows directly from their desires -- which makes it designed -- and they will continue to try to prove it there, on Mars, and elsewhere.

This is why I point to the work of Daniel Kahneman: When people imagine that they can think scientifically, without understanding how our mind deals with these narratives, the role of the narratives in our thinking processes becomes obscured. The line that separates rational from irrational becomes blurred. Rather than being an object we can inspect, we become subject to them.

We WANT there to be oceans. That would make for a better story, and so this is what they look for. But, a cautious scientist will look at his desires as an impediment to thinking objectively. Focusing upon the narratives obscures emergent phenomena.
HannesAlfven
1 / 5 (3) Mar 26, 2014
All worldviews come with narratives. The EU has their own, of course. This is our intuition speaking to us. We can't stop it from speaking to us. What we CAN do, however, is learn to identify WHEN IT IS SPEAKING TO US. And that will make the entire world a more scientific place to have conversations.

See A Psychological Perspective on Rationality
https://www.youtu...utgSwY88

... especially the part where he defines associative coherence, and the distinction between System 1 and System 2. Think through his examples, and notice that you can formulate extremely specific judgements about a subject without knowing more than just two details. This is not rational thinking, and yet, we all come with an ability to do it without any effort whatsoever. We don't get to decide. It happens TO us.

The arguments and evidence are then tracked down to post-rationalize the narrative. We all have a choice to make: Either learn how it works, or be subject to its application.
Jizby
Mar 26, 2014
This comment has been removed by a moderator.
barakn
4 / 5 (4) Mar 26, 2014
I see that Hannes has no rational arguments and has wandered off into the usual semantic ramblings. What he's desperately trying to hide here is that I did assume the EU world view to be true. I assumed the surface of Titan was electromachined. I also took evidence from Casinni and Huygens, evidence which should be incontrovertible no matter which worldview we are using, that the surface of Titan is a rock made predominantly of water ice. It takes no great mental effort to realize that the bottom of an electromachined ice bowl should be ice, and that if the electromachined substance forms a lava, that lava must be ice water, and if it solidifies within the electromachined bowl, it must have formed a layer of ice. If there's something wrong with the setup so far, Hannes should have pointed it out, and provided a corrected version. He should discuss the physics, because by assuming a tenet of EU to be true, I have met him far more than halfway.
paulrwalsh
not rated yet Apr 03, 2014
Peter_Beaumont is right.
This article says, "Saturn's second largest moon, Titan ...."

But Titan is the largest of Saturn's moons, not the second largest.