New Views of Titan’s Lake Country

by Paul Gilster on December 17, 2013

Titan has about 9000 cubic kilometers of liquid hydrocarbon, some forty times more than in all the proven oil reservoirs on Earth. That’s just one of the findings of scientists working over the data from recent Cassini flybys of the Saturnian moon. Each flyby snares our attention because this is the only other place in the Solar System that has stable liquid on the surface, even if it’s not water. That’s part of Titan’s fascination, of course, because it’s similar to the Earth in terms of basic interactions between liquids, solids and gases but completely alien in terms of temperatures.

Just how extensive are those seas and lakes we’ve found in Titan’s northern hemisphere? Cassini’s radar instrument has given us our best views to date with the mosaic shown below, one that’s based on multiple images from flybys tracking areas at various angles. Kraken Mare, Titan’s largest sea, and Ligeia Mare, the second largest, appear along with nearby lakes. We learn not only that Kraken Mare is more extensive than first thought, but that almost all the lakes on Titan are in an area some 900 kilometers by 1800 kilometers. A mere three percent of the liquid on Titan is found outside this region. Cassini radar team member Randolph Kirk explains:

“Scientists have been wondering why Titan’s lakes are where they are. These images show us that the bedrock and geology must be creating a particularly inviting environment for lakes in this box. We think it may be something like the formation of the prehistoric lake called Lake Lahontan near Lake Tahoe in Nevada and California, where deformation of the crust created fissures that could be filled up with liquid.”

This JPL news release adds that processes like these on Earth lead to the formation of faults that create basins broken by mountain ranges. Much of present day Nevada was, some 13,000 years ago, flooded by Lake Lahontan in a configuration that resembles, on a smaller scale, Titan’s closely packed seas.

titan_lakes_1

Image: This colorized mosaic from NASA’s Cassini mission shows the most complete view yet of Titan’s northern land of lakes and seas. In this projection, the north pole is at the center. The view extends down to 50 degrees north latitude. In this color scheme, liquids appear blue and black depending on the way the radar bounced off the surface. Land areas appear yellow to white. A haze was added to simulate the Titan atmosphere. Kraken Mare, Titan’s largest sea, is the body in black and blue that sprawls from just below and to the right of the north pole down to the bottom right. Ligeia Mare, Titan’s second largest sea, is a nearly heart-shaped body to the left and above the north pole. Punga Mare is just below the north pole. Credit: JPL.

Note the smaller lakes above and to the left of the north pole, which are about 50 kilometers across or less. Moreover, the new data are finally telling us how deep at least one of the seas is. Because the liquid methane of Ligeia Mare is very pure, Cassini’s radar signal passes through it easily and can detect a signal from the sea floor. The lake turns out to be about 170 meters deep, and in at least one place is deeper than the average depth of Lake Michigan. With northern summer approaching, Titan’s lake country should be entering an interesting meteorological phase for Cassini’s future studies as the atmosphere heats up.

tzf_img_post

{ 26 comments… read them below or add one }

Rob Flores December 17, 2013 at 14:04

Just an observation on the location of the crust fault location.
Is it a coincidence that these 3 moons Europa, Enceladous, and Titan have only ONE pole not two that faulted/cracks to permit Outgassing into space or liquid pooling as in Titan (with more PP Europa & enceladous would probably form H2O lakes). It just seems strange that the effect does not
seem to affect the opposite poles of these moons.

Also are we sure these largest lakes on Titan are truly separate, could they
be connected by unseen channels. Or for that matter is the Ice so porous and unsettled in that polar region, that what we are looking is the pooling of hydrocarbons where the ground is best able to absorb them. So that the
entire region is a hydrocarbon sink.

Too bad about the distances involved to Titan, But on the brigth side once there a simple reactor for heating and separation of ()2 should create a nice portable sources of energy for surface missions.

Charley December 17, 2013 at 14:52

this the place to land; drop a surface/submersible nuc. powered
vehicle in this lake – I’d bet we’d get some fantastic data

David Cummings December 17, 2013 at 15:24

“Titan has about 9000 cubic kilometers of liquid hydrocarbon, some forty times more than in all the proven oil reservoirs on Earth. ”

Here’s a test-firing of a methane rocket back in 2007:

http://science1.nasa.gov/science-news/science-at-nasa/2007/04may_methaneblast/

Daniel Suggs December 17, 2013 at 17:21

Paul, under the image, “Ligeia Mare, Titan’s second largest sea, is a nearly heart-shaped body to the left and above the north pole. ”
Shouldn’t that be ‘…to the RIGHT and above…”? That’s what it looks like from here anyway. Thanks, always interesting to hear more on Titan.

David Cummings, interesting link.

Paul Gilster December 17, 2013 at 21:39

I had the same reaction, Daniel. But I think what they were trying to say is that Ligeia Mare was somewhat to the left of Kraken Mare while still above the pole. I left it as the JPL people had it, but with some reservations.

Holger December 18, 2013 at 9:47

@Rob Flores:
“Is it a coincidence that these 3 moons Europa, Enceladous, and Titan have only ONE pole not two that faulted/cracks to permit Outgassing into space or liquid pooling as in Titan (with more PP Europa & enceladous would probably form H2O lakes). It just seems strange that the effect does not
seem to affect the opposite poles of these moons.”
Titan does have at least one lake at the south pole (Ontario Lacus). According to
https://en.wikipedia.org/wiki/Lakes_of_Titan, ” Due to the eccentricity of Saturn’s orbit, the northern summer is longer than the southern summer and consequently the rainy season is longer in the north.”

Also Titan’s lakes have only been observed during northern winter/early spring (since each season takes 7 years); the northern lakes might (partially) evaporate and rain down in the south during northern summer, similar to the Martian icecaps.

ljk December 18, 2013 at 10:34

Charley said on December 17, 2013 at 14:52:

“this the place to land; drop a surface/submersible nuc. powered
vehicle in this lake – I’d bet we’d get some fantastic data.”

Are you familiar with this Titan lake mission concept:

http://www.centauri-dreams.org/?p=28623

James M. Essig December 18, 2013 at 16:06

One thing that come to mind regarding the 9,000 cubic km of hydrocarbons is the possibility of far more locked up under the surface.

As a nuclear energy freak, I’d welcome the use of the carbon in any possible C-N-O bicycle powered ISR craft.

With all that carbon, a stupendously large fleet of ISR craft could be operated out of our solar system.

The biggest Caveat here is not the fusion or the carbon supply, but good acceleration of ISR craft to relativistic velocities amidst interstellar drag.

I believe a new generation of ISR researchers are working to remedy the drag issues in theory.

Ahhhh! Fusion! As natural as the noon-day Sun.

Rob Flores December 18, 2013 at 19:18

Holger: That is a lot of eccentricty. close to 10% change in proximity to the sun, summer to winter. If we havent seen summer yet, then torrential methane rains, should solve part of the mystery of mass wasting on Titan.

We should try to time a surface probe/floater to near the later stages of
summer on Titan, that way we would get thorough data on winds and precipitation, while having the option to wait in orbit if the climate makes it too hazardous to descend to the surface.

David Cummings December 19, 2013 at 8:19

James, I suspect you are correct, that there are more hydrocarbons on Titan than meet the eye, and I agree with you, their use in C-N-O fusion power is an exciting prospect.

william f collins December 19, 2013 at 11:49

Paul, thank you for your recent blogs re: Europa and Titian. It is ironic that three moons , Enceladous, Titan, and Europa are prime candidates for the existence of free flowing liquid bodies (water, methane, oil, or otherwise ) in our solar system vice one out of eight planets. Perhaps these moons may also be the best candidates for the first verifiable discovery of extraterrestrial life of some sort. In any case,the exploration, exploitation , or perhaps even the settlement of these moons will be key component in our development as a spacefaring race. Interplanetary space travel needs to have an economic component – safer, faster, and cheaper than what our technology is currently. I certainly am looking forward to a successful test of Dr. Chang’s VASMIR(?) engine as well as the solar sail and other proposals. Finally, I do wonder about the the dangers to potential human crews – radiation on Europa, extreme cold on Titan and Encedalous , the physical and psychological stresses on human crews, the great distances from any possibility of rescue, etc- who made these flights. However, the possible benefits would be worth the risks.!

Andrew Palfreyman December 19, 2013 at 15:44

Perhaps it’s possible that, one day, some bright spark is going to ignite Titan

ljk December 19, 2013 at 17:02

Andrew Palfreyman said on December 19, 2013 at 15:44:

“Perhaps it’s possible that, one day, some bright spark is going to ignite Titan.”

Can lightning form in Titan’s atmosphere? How about a fire on the surface?

Eniac December 20, 2013 at 0:58

Alas, there is no precious fuel on Titan, and sparks would produce no reaction whatsoever. What is precious on Titan is oxidants, of which I bet there aren’t a lot around, there. Earth is a very special place, with oxidant (O2) and reductant (biomass) intermingled in close, precarious proximity. This sort of profound disequilibrium is only possible because of the miracle of photosynthesis, and is found nowhere else in the known world.

You might think taking oxidant from one planet and combining it with reductant from another would be a great source of power. Alas, this is also untrue. The energy spent pushing the components out of their respective gravity wells is more than what could be gained in combining them.

Moebius December 20, 2013 at 7:42

@Andrew Palfreyman: no, because you need O2 to burn hydrocarbons.
Unless we introduce tremendous amounts of oxygen into Titan’s atmosphere there is no risk to ignite Titan.
However every astronaut we send on Titan should not let his spacesuit leak, at the risk of becoming a human torch (but at 94K, I think he would more likely freeze than burn).

Andrew Palfreyman December 20, 2013 at 7:57

On reflection, there is a dearth of free oxygen required for ignition, so ignition seems unlikely.

Rob Flores December 20, 2013 at 13:13

Well, on the surface of TITAN, I was going to suggest making simple reactor
to heat Ice to melting point, provide Electrolysis to create O2 and H2, then Gather some methane and combust it.

But it turns out if you have to create H2 and O2 anyway just
combust the hydrogen, it gives you 2.54 times more energy, than methane.
Leave the Hydrocarbons to create PLASTICS.

I know hydrogen will tend to leak from any storage, but any base will need the “excess” O2 for it’s occupants so maybe a happy balance can be established.

Rob Henry December 20, 2013 at 18:27

Wow so many comments that are almost right, or correct but misleading

Eniac says “Alas, there is no precious fuel on Titan…”, and it seems so, but let’s never forget all that missing acetylene. If it is just buried in shallow but high concentrations then we do have a precious fuel that we could combine with the ambient H2 (actually, more like a precious oxidant).

Moebius wrote “However every astronaut we send on Titan should not let his spacesuit leak, at the risk of becoming a human torch” and there is absolutely no risk of that without a spark – and that possibility should be easy to eliminate. Methane is not terribly toxic, but we wouldn’t want too much of it in the suit. It could leak like a sieve as long as sufficient heat was retained the dash back to the landing capsule would only be for long term health reasons.

And to Rob Flores my guess is that, wherever we burn that oxygen it will be with methane not oxygen (save for the return rocket) even though it is only about a couple of percent of the atmosphere. The reason is that cryogenic hydrogen is difficult to transport from the power source where it is generated, and, on Titan, methane is not. If we are by a lake or river, we do not even need to transport it, just scoop it up and put it in our barbeque.. or any other bit of portable essential equipment.

PS. Moebius, high pressure hydrogen mixed with helium and oxygen has been used on ultra deep diving experiments – so lowering the risk of sparking to zero is easy in practice, and not just theory.

Michael December 21, 2013 at 14:00

@Rob Henry

‘Eniac says “Alas, there is no precious fuel on Titan…”,
Rob Henry says ‘and it seems so, but let’s never forget all that missing acetylene. If it is just buried in shallow but high concentrations then we do have a precious fuel that we could combine with the ambient H2 (actually, more like a precious oxidant).’

High purity Acetylene can spontaneously explode with extreme violence when put under pressure due to a sensitive bond structure.

Eniac December 23, 2013 at 23:21

Michael: I have trouble envisioning the chemistry of this, and have found nothing on the web that would explain what you seem to be talking about. Could you elaborate, please? Are you saying pure acetylene will exothermally convert to something else? Without oxidant or other compounds present? Not likely…

I think what Rob Henry refers to is the reaction of acetylene with hydrogen gas, which may be slightly exothermal, although I am not sure of this.

Rob Henry December 24, 2013 at 15:31

Eniac – it could only convert to benzene which releases 6,400 kJ/kg. I am now reading here
http://www.newworldencyclopedia.org/entry/Acetylene
under the heading “compression” that the danger zone is 100,000 Pa – which seems ridiculously low.

Eniac December 30, 2013 at 20:21

Rob: Here (http://www.newworldencyclopedia.org/entry/Acetylene#Compression) it says:

Acetylene can be decomposed to its elements with the liberation of heat. The decomposition may or may not give rise to explosions, depending on conditions. Pure acetylene under pressure in excess of about 15 pounds per square inch or in liquid or solid form explodes with extreme violence.

From this I surmise that pure acetylene decomposes into H2 and carbon, exothermally, at least to produce this “extreme violence” that is cited.

Benzene needs three molecules to come together, which appears to only occur with the help of a catalyst, without “extreme violence”.

Eniac December 30, 2013 at 20:24

Just noticed my citation is the same as yours. Note the “decomposed to its elements” part, though.

Rob Henry December 31, 2013 at 23:13

On rereading, the implication looks to me that the reaction leads to a complex mix that includes hydrogen, ‘soot’, benzene and C4H4. The fact that pressure triggers it would imply that benzene and C4H4 are its first major products, with hydrogen (and presumably sooty graphite) only being released once the temperature rises over 400C. If so this would explain why neither of us can find a simple reference for ‘the’ reaction.

Still, I can’t shake the image alluded above of the whole moon exploding once one of these deposits are detonated. Pulp Sci-iFi loves that piece of bad science. Still, individual deposits could explode, given just the right conditions.

Dmitri January 31, 2014 at 16:16

In summer I took a series of macro shots of 40 year old industrial grade paint cracking and peeling off. I forgot about some of them or didn’t know how or to what to render them. Seeing this article, especially the lakes’ topographic cover photo, I instantly recalled them and took on to have another look. I recalled that I had something close to mares of Titan.

One just stuck out on naming in Ligeia Mare. I just feel it as mare / lacūs.

I referred from there back to this article.

http://500px.com/photo/59269116

ljk March 18, 2014 at 12:09

First hints of waves on Titan’s seas

Reflections on the oceans of Saturn’s largest moon suggest long-sought extraterrestrial ripples.

Alexandra Witze

17 March 2014

THE WOODLANDS, TEXAS

After years of searching, planetary scientists think they may finally have spotted waves rippling on the seas of Titan, Saturn’s largest moon. If confirmed, this would be the first discovery of ocean waves beyond Earth.

NASA’s Cassini spacecraft spied several unusual glints of sunlight off the surface of Punga Mare, one of Titan’s hydrocarbon seas, in 2012 and 2013. Those reflections may come from tiny ripples, no more than 2 centimetres high, that are disturbing the otherwise flat ocean, says Jason Barnes, a planetary scientist at the University of Idaho in Moscow.

Barnes presented the findings today at the Lunar and Planetary Science Conference, where a second talk hinted at the presence of waves in another of Titan’s seas.

Researchers expect more waves to appear in the next few years, because winds are anticipated to pick up as Titan’s northern hemisphere — where most of its seas are located — emerges from winter and approaches spring.

“Titan may be beginning to stir,” says Ralph Lorenz, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. “Oceanography is no longer just an Earth science.”

Full article here:

http://www.nature.com/news/first-hints-of-waves-on-titan-s-seas-1.14889

To quote:

Calculations of the waves’ height suggested they were a puny few centimetres high. “Don’t make your surfing plane reservation for Titan just yet,” Barnes told the conference.

Leave a Comment