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Titan Has Liquid Lakes, Scientists Report in Nature Jan. 3, 2007 (Source: JPL)

Liquid Lakes on Titan The existence of oceans or lakes of liquid methane on Saturn’s moon Titan was predicted more than 20 years ago. But with a dense haze preventing a closer look it has not been possible to confirm their presence. Until the Cassini flyby of July 22, 2006, that is.

Scientists report definitive evidence of the presence of lakes filled with liquid methane on Saturn’s moon Titan in this week’s journal Nature cover story.

Radar imaging data from a July 22, 2006, flyby provide convincing evidence for large bodies of liquid on Titan today. A new false-color radar view gives a taste of what Cassini saw. Some highlights of the article follow below.

Here’s the full version of the graphic:

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Sadly, methane has a dipole moment of 0 and is probably not able to act as a solvent for nearly as many interesting molecules as water.

Wow. Just… wow. All this mystery and wonder, questions leading to more questions… Excuse me while I wipe the space geek drool from my chin, as I speculate on what the Pluto probe will be showing us in a few more years…

If:

1. melting point of Methane is -182C; 2. boiling point of Oxygen is -183C; 3. CH4 + 2O2 → CO2 + 2H2O; 4. water melting point 0C; 5. CO2 sublimates at -78C,

then what happens if you go to Titan and light a match? Do you get water and CO2 ice cubes? Or will someone take all the fun out of it and confirm there is no oxygen on Titan?

(I appreciate that the above temperatures are at 1 atm but I assume (maybe incorrectly) that the boiling point of oxygen would still be less than melting point of methane and melting point of water is still higher than the melting point of methane at less than 1 atm.)

I am so glad that we have this kind of program. It’s beautiful and humbling to see these and all of the images and learn about those things that have existed and been formed outside of all human experience. Awestruck.

“methane has a dipole moment of 0 and is probably not able to act as a solvent…”

BUT, if you get a little acetonitrile, or HCN mixed in to your liquid methane, you’ve got solvent.

I forget what the story was on the detection of larger organics on Titan-still controversial?

This article, believe it or not, is relevant to the evolution/creation debate. David Coppedge, the head honcho of Creation/Evolution headlines, made a big issue in 2003 of some glimpses through the clouds on Titan that seemed to show a high-relectivity solid-surface. Aha, said Coppedge,

This is one of many phenomena in the solar system that argue against the commonly-accepted age of 4.6 billion years. (1) In the first place, all the methane should have eroded by now into products blanketing the surface. (2) In the second place, if organic compounds have been raining down to the surface for that long, there should be a blanket over half a mile thick covering any water-ice surface, yet today, water ice is detectable.

To keep the long age, scientists have to propose a continual source of new methane to replenish the atmosphere that we see, from the interior or some unknown external source, or have to find a way for the methane products to disassemble back into methane in some kind perpetual cycle. But this is storytelling without evidence. Methane is eroding in the Titan atmosphere, which should blanket the moon with dark organic residues, yet water ice is visible from the surface. These are the data, folks. Make up stories of billions of years at your own risk.

Well, three years later, it turns out there are low-reflectivity lakes containing methane and organics, there is an extensive seasonal polar ‘hood’ of dark organics (see references in the Nature article) which is continually recycled by the climate, and there is extensive ethane.

Will Coppedge be correcting his errors (including the chemical illiteracy of ‘methane eroding’)? Sure, when the lakes of Titan freeze over.

Corbs,

Actually, according to this link, the pressure of Titan’s atmosphere is about 60% percent higher than earth’s atmosphere, or about 1.6 atm. This means that O2 and CO2 will have higher boiling and sublimation temperatures, respectively, than they do on earth. Using the Clausius-Clapeyron equation, I calculate that O2 would boil at -173C and CO2 would sublimate at -73C.

Melting points typically do not depend very strongly on pressure, and the difference between 1 atm and 1.6 atm will make only a very small (and therefore negligible) change to the melting points of methane and water.

Your table would more accurately look like this: 1. melting point of Methane is -182C; 2. boiling point of Oxygen is -173C; 3. CH4 + 2O2 → CO2 + 2H2O; 4. water melting point 0C; 5. CO2 sublimates at -73C,

Again, according to the link above, the average surface temeprature of Titan is -178C. Thus, oxygen, if it is present, would be in the gas phase, at least near the surface.

According to the atheists at Kansas Citizens therefore the war in Iraq is a conservative plot, God does not exists, and Robert Madison is a advocate of science.

Of course, he gave up teaching for sales, but whatever.

Sorry for the typo. I meant to say that oxygen would be in the LIQUID phase, at least near the surface. Because the surface temperature of Titan is so close to the boiling point of oxygen, there would be a significant amount of oxygen in the gas phase.

Sorry for the typo. I meant to say that oxygen would be in the LIQUID phase, at least near the surface. Because the surface temperature of Titan is so close to the boiling point of oxygen, there would be a significant amount of oxygen in the gas phase.

If there was any free oxygen, which I gather there isn’t, because it is a reducing atmosphere:

Nitrogen - 98.4 percent Methane - 1.6 percent

according to wikipedia.

Sadly, methane has a dipole moment of 0 and is probably not able to act as a solvent for nearly as many interesting molecules as water.

I think the main problem for life on Titan is that the cold temperatures mean it would take a lot of energy to get carbon reactions to their activation energies, and therefore any such reactions would procede extreeeeemly sloooooowly. At least, that’s what some chemistry guy told me once.

I think what this demonstrates is the sheer diversity of environments possible. We have so many extremes and different mixes of elements, atmospheres, tidal forces, all within one solar system. The possibilities outside this already varied locale are endless.

The Pluto probe will probably show us… a dwarf planet. :)

Thanks, Nick, for pointing out that there’s essentially no oxygen in Titan’s atmosphere. A little nitpick, though: the presence of nitrogen and methane do not make it a reducing atmosphere. Nitrogen is basically inert, and methane won’t reduce much of anything, particularly not (as you point out) at the very low temperature of -178C.

What the chemistry guy told you is correct: at such low temperatures there isn’t enough thermal energy to overcome the activation energies associated with important chemical reactions. However, it is interesting to note that on planets and moons without ozone (no oxygen means no ozone), there is nothing to block UV light from reaching the planet surface, so light-activated reactions can proceed.

Lydia’s Friend wrote some things that are worth addressing, because they reveal more than the author may have intended…

“According to the atheists at Kansas Citizens…”

I assume that this is a reference to Kansas Citizens for Science. What do the rest of them think?

“…therefore the war in Iraq is a conservative plot,”

I’ve never been to Kansas, and don’t consider myself an atheist. I’ll admit that I strongly oppose the war in Iraq, but I think that even supporters would admit that it’s probably fair, if critical, to refer to it as a “conservative” venture, and that “plot” may fit the efforts of the run-up. But that’s not important (in this context).

Here’s what’s important. Methane on Titan and the theory of evolution have no direct relevance to any interpretation of the war in Iraq. Aren’t you suggesting that “ID” is endorsed almost exclusively by people who hold a certain political view? Doesn’t that argue rather strongly that it is neither a valid scientific view, nor even, for that matter, a sincere religious idea?

“ …God does not exists, and Robert Madison is a advocate of science.

Of course, he gave up teaching for sales, but whatever.”

This is pretty incoherent, it suggests an irrational defensive reaction. Naturally, people who are not professional scientists, but who work in business, law, or whatever else, are often strong advocates of science.

From what little I can glean, Robert Madison appears to be vocal as an atheist. Most of the atheists who post here are very strong supporters of science (duh), but there are plenty of less-educated atheists who are vocal advocates of “UFOlogy”, various unproven “alternative medicine” ideas, and whatnot, and who are less enthusiastic about mainstream science.

There’s certainly a tendency for atheism and respect for science to travel together, and by definition a few types of fundamentalist belief contradict science, and there are many atheists who insist that science contradicts all religious beliefs. However, that doesn’t change the fact that some scientists and science supporters hold religious beliefs, and others may not, but are more respectful and tolerant than the most strident atheists.

However, this looks like a clumsy attempt to set up a straw man. What relevance does Robert Madison have to this story? Aren’t you, once again, admitting that “ID-related” anti-science claims are grounded in irrelevant political or social concerns?

What the chemistry guy told you is correct: at such low temperatures there isn’t enough thermal energy to overcome the activation energies associated with important chemical reactions. However, it is interesting to note that on planets and moons without ozone (no oxygen means no ozone), there is nothing to block UV light from reaching the planet surface, so light-activated reactions can proceed.

Except for moons like Titan, which have a thick hydrocarbon haze that blocks the UV from reaching the surface. I gather they do think the UV causes reactions higher up in the atmosphere.

LOL.…what are the chances of a conversation, this scientifically indepth, is going on at AIG or the Disco Institute.

NOT!…plus, I think the sent all their crayons out for sharpening.

Except for moons like Titan, which have a thick hydrocarbon haze that blocks the UV from reaching the surface. I gather they do think the UV causes reactions higher up in the atmosphere.

Even without the haze, would the UV flux at the surface be greater than it is for Earth? Titan’s a whole lot farther away from the primary UV source in the solar system.…

I’m not sure, Anton. I thought I read somewhere that the hydrocarbon haze on Titan was the result of UV-initiated reactions in the atmosphere. The UV flux at Titan might be well below that on earth, but I think it’s enough to make some interesting chemistry happen.

I’m not sure, Anton. I thought I read somewhere that the hydrocarbon haze on Titan was the result of UV-initiated reactions in the atmosphere. The UV flux at Titan might be well below that on earth, but I think it’s enough to make some interesting chemistry happen.

The intensity of solar radiation will decay as a square of distance IIRC (because it is getting more spread out), so with Saturn at 9.5 times the distance from the sun as the earth, so I assume the UV radiation at the top of Titan’s atmosphere will be ~90 times less intense than at the top of Earth’s atmosphere. This doesn’t mean the photon energies will be weaker on average, just that there are fewer total photons of all energies.

Quoth wikipedia, the font of all knowledge:

The atmosphere is 98.4% nitrogen — the only dense nitrogen-rich atmosphere in the solar system aside from our own — with the remaining 1.6% composed of methane and only trace amounts of other gases such as hydrocarbons (including ethane, diacetylene, methylacetylene, cyanoacetylene, acetylene, propane), argon, carbon dioxide, carbon monoxide, cyanogen, hydrogen cyanide and helium.[13] The hydrocarbons are thought to form in Titan’s upper atmosphere in reactions resulting from the breakup of methane by the Sun’s ultraviolet light, producing a thick orange smog. Titan has no magnetic field and sometimes orbits outside Saturn’s magnetosphere, directly exposing it to the solar wind. This may ionize and carry away some molecules from the top of the atmosphere

Thanks Nick and Laser.

Ah well, no Titan go boom.

It has made me curious though as to why Titan, which is significantly smaller than earth and with significantly less gravity has significantly greater atmospheric pressure than earth. Both have predominately nitrogen atmosphere, but ours also has about 20% oxygen and Titan about 1.6% methane. The atomic weights are not that different. Is the lower temperature meaning more molecules per cubic meter the deciding factor? If so why does Venus have such a high pressure atmosphere?

Sorry if this is a basic question.

It has made me curious though as to why Titan, which is significantly smaller than earth and with significantly less gravity has significantly greater atmospheric pressure than earth. Both have predominately nitrogen atmosphere, but ours also has about 20% oxygen and Titan about 1.6% methane. The atomic weights are not that different. Is the lower temperature meaning more molecules per cubic meter the deciding factor? If so why does Venus have such a high pressure atmosphere?

Sorry if this is a basic question.

It’s not a basic question. I once asked a planetary scientist about this and he said, basically, “Atmospheric density is poorly constrained by mass.” One would think more mass = more atmosphere but it turns out that is not the case in any regular way, at least within the range of moon-to-Earth sized bodies.

Some factors that I gather come into play (notes: IIRC, and IANAPS (I Am Not a Planetary Scientist)):

* Major impacts: the earth-moon system was formed by a massive collison of an earth-size body and a Mars-size body. This probably drove off a lot of volatiles that would otherwise be present (and are present on Venus).

* Atmospheric freeze-out: if your gases freeze out, you’re pretty much stuck. I think this happens to CO2 on Mars.

* Weathering: water+rocks=CO2 being scrubbed out of the atmosphere. If you have plate tectonics, this is eventually recycled, but if you are like Mars, again, you’re stuck.

* Loss to space – I gather this depends on things like the temperature/speed of the molecules at the top of the atmosphere, as well as molecule mass and planet mass, and whatever may be bombarding the planet (protective magentic field helps against solar wind, high-energy particles from Jupiter’s magnetic field do not, etc.)

…and I’m sure there are other things I haven’t remembered. Then all these factors interact for four billion years and produce great variation. The wikipedia atmosphere page and this page have a bit more.

Isotope differences are mostly what it used to test hypotheses of the evolution of atmospheres over time.

It has made me curious though as to why Titan, which is significantly smaller than earth and with significantly less gravity has significantly greater atmospheric pressure than earth. […]

It likely has to do with average speed of the molecules, relative to escape velocity for the planet or moon.

Lower average speed (i.e., colder), combined with smaller gravity, could go either way depending on the specific numbers.

Venus - I’m not sure, but it might be that it’s high surface temperature vaporizes a bunch of stuff that’d be liquid or solid here.

Henry

Amendment to my previous post after reading Nick’s reply:

I was thinking only of substances that would be gaseous if already present, and whether said molecules would be apt to escape into space. If the gaseous material tends to leave the atmosphere (whether by escaping, condensing, freezing, dissolving, or combining chemically with something), then there would have to be something to replenish it.

Henry

Thanks for those nuggets about atmospheric density and some of the factors involved, Nick. Fascinating, and another example of how physical laws operate in counter-intuitive ways.

FWIW, the escape velocity from Titan is about 8350 m/s. At -178 C, the average velocity of nitrogen is 270 m/s and that of methane is 355 m/s. Neither of those molecules would be fast enough to escape under Titan’s current conditions. In fact, hydrogen’s average velocity under those conditions is about 1000 m/s, so even the lightest molecule would be unlikely to escape Titan’s atmosphere now.

Gerard Harbison Wrote:

Will Coppedge be correcting his errors (including the chemical illiteracy of ‘methane eroding’)? Sure, when the lakes of Titan freeze over.

Or when YECs start framing their radical assertions primarily as challenges to OEC, and thus most implied positions of IDers. Which will be after all lakes - and Saddam Hussein’s new home - freeze over.

FWIW, the escape velocity from Titan is about 8350 m/s. At -178 C, the average velocity of nitrogen is 270 m/s and that of methane is 355 m/s. Neither of those molecules would be fast enough to escape under Titan’s current conditions. In fact, hydrogen’s average velocity under those conditions is about 1000 m/s, so even the lightest molecule would be unlikely to escape Titan’s atmosphere now.

I think in this case it’s not so much about the average as the fastest-moving molecules in the distribution, which, in the thin upper atmosphere, is highly variable from molecule to molecule (IIRC).

Re “I think in this case it’s not so much about the average as the fastest-moving molecules in the distribution, which, in the thin upper atmosphere, is highly variable from molecule to molecule (IIRC).”

Yeah - like the helium in Earth’s atmosphere. An atom at the average speed won’t escape, but the rate per unit time is measurable (and balanced by escape of helium from the Earth where it gets produced by radioactive decay).

Henry

(p.s. Wonder if we can get “iirc” added to the spell checker?)

It’s even more complicated than that, because the temperature varies with the altitude, typically decreasing as altitude increases. (I couldn’t find any information on the temperature on Titan as a function of altitude–Nick do you have any info?) At low temperatures, the Maxwell-Boltzmann distribution is quite narrow, so the likelihood that many molecules exceed the escape velocity is quite low. Sorry, but I don’t have time right now to do the numerical integration to find the exact fraction of molecules that would escape.

Question - does a planetary magnetic field make it harder, or easier (or neither) for atoms or molecules to get away from it all?

Henry to quote Nick from earlier:

Nick (Matzke) Wrote:

Loss to space — I gather this depends on things like the temperature/speed of the molecules at the top of the atmosphere, as well as molecule mass and planet mass, and whatever may be bombarding the planet (protective magentic field helps against solar wind, high-energy particles from Jupiter’s magnetic field do not, etc.)

It’s even more complicated than that, because the temperature varies with the altitude, typically decreasing as altitude increases.

It’s even more complicated than that, because in most Earth layers the temperature increase with altitude. For example, the Earth thermosphere inversion means the exosphere has markedly higher temperature than the troposphere. ( See picture at http://en.wikipedia.org/wiki/Ionosphere )

does a planetary magnetic field make it harder, or easier (or neither) for atoms or molecules to get away from it all?

Several mechanisms here. On inner planets it seems UV dissociation and solar wind net contribution results in depletion of hydrogen. The solar wind here sputters away more hydrogen than it contributes, evidently. ( http://en.wikipedia.org/wiki/Atmospheres )

The Earth magnetic field diminishes the solar wind. It also traps ionized particles both from without and within, which leaks out, partly onto the atmosphere, at the magnetic poles. (Auroral lights.) If the later results in net loss or gain I don’t know.

People responding in here wonder what we’re going to see at Pluto. Why not something like a repeat of Neptune’s weird-surfaced moon Triton which, I take it, is thought to be a captured Kuiper Belt Object? –I can’t possibly be the only person who’s thought of this

Huygens’s second landing anniversary — the surprises continue

Two years ago, planetary scientists across the world watched as Europe and the US did something amazing. The Huygens descent module drifted down through the hazy atmosphere of Saturn’s moon Titan, beaming its data back to Earth via the Cassini mothership. Today, Huygens’s data are still continuing to surprise researchers.

(“Surprise, surprise, surprise!”, as Gomer would say.)

At the surface of Titan, Huygens measured the temperature to be 94 ºK (-179 ºC) with a humidity of 45 percent.

(Ewwww!)

Henry

Seas on Titan:

The imaging cameras, which provide a global view of Titan, have imaged a much larger, irregular dark feature. The northern end of their image corresponds to one of the radar-imaged seas. The dark area stretches for more than 620 miles in the image, down to 55 degrees north latitude. If the entire dark area is liquid-filled, it would be only slightly smaller than Earth’s Caspian Sea. The radar data show details at the northern end of the dark feature similar to those seen in earlier radar observations of much smaller liquid-filled lakes. However, to determine if the entire dark feature is a liquid-filled basin will require investigation through additional radar flyovers later in the mission.

http://www.nasa.gov/home/hqnews/200[…]i_lakes.html

Glen D

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