Get your beachfront property now...

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 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.

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.

Nitrogen - 98.4 percent Methane - 1.6 percent

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 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.

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.

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 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 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. [...]

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.

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

— Gerard Harbison

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.

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?

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.)

— Nick (Matzke)

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

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

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

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.

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

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.

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