Flammability of Oxygen on Titan?

thalion · Jan 23, 2005

There was an entertaining short story written by Isaac Asimov some time ago involving a mystery over a murder on Titan. In the story (written after it was known that there was methane on Titan), the weapon is a tank of oxygen that is made to combust in Titan's atmosphere, opposite of the situation on Earth. It's sort of common knowledge that oxygen cannot burn in itself, but that it can support combustion. However, my question is: would oxygen on Titan really be a flammable gas, the same way methane is a flammable gas on Earth?

bs2taa · Jan 24, 2005

Well, I'm new to this stuff, but seeing as people don't post much I geuss I'll post what I think. On earth, I believe our atmosphere is 21% oxygen. Any lower than 17% and we would die, and any higher than 25% and then I believe that it would become a flammable gas as your talking about. It's a high possibility, it just happens to be luck that earth has just the right amount of gases to support out life. When you say flammable, do you mean as in strike a match and the entire planet explodes?

vogon13 · Jan 24, 2005

Titan atmosphere mostly nitrogen, not saying a jet of oxygen wouldn't have a flame thrower effect on a puddle of liquid CH4 on ground but I am still wondering what percentage CH4 in mostly N2 atmosphere would be dangerous with a jet of pure O2 and a jet of 80%N2/20% O2. Suspect doing experiment on earth in anything short of properly equiped laboratory would be extremely dangerous. Don't try this at home! <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

vogon13 · Jan 24, 2005

...happens to be luck that earth has just right amount of gases to support life... I feel human life evolved to mix of gases present, drastically different mix of gases and we would all have different enzymes/respiratory organ structure, metabolic system, etc. S. Hawking has some intruiging thoughts on this topic. ( I am aware early life forms on earth modified primordial atmosphere) ...strike match and planet explodes... Meteor impacts have been "striking the match" so to speak for billions of years and Titan hasn't exploded yet. <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

claywoman · Jan 24, 2005

Yes, but Vogon how many meteors have oxygen which I believe is needed on Titan for a catalyst...I could be wrong but unless one brings massive amounts of oxygen with them, being hot is not going to do something except possibly melt the ice for a second....I may be wrong here...

thalion · Jan 24, 2005

By the way, the story was "The Dust of Death", first published in January 1957 in Venture Science Fiction, and later put in an anthology titled Asimov's Mysteries, published in 1968.

vogon13 · Jan 24, 2005

My point, indeed! NASA/ESA and mother nature too, unable to bring to planet a planet incinerating volume of O2 to Titan. Spark by itself unable to ignite Titan. <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

heyo · Jan 24, 2005

Titan atmosphere mostly nitrogen, not saying a jet of oxygen wouldn't have a flame thrower effect on a puddle of liquid CH4 on ground But you'd still need a spark for that, right? To ignite the CH4-Oxygen mixture? And the oxygen would burn using the methane in the air when it's ignited, the same way that on earth if you had a methane it would burn using the oxygen from the air? Like the same effect as Earth but reverse chemistry? But you DO still need a spark, right? It wouldn't spontaneously combust I don't think.. Heyo

Saiph · Jan 24, 2005

It's just as dangerous as having methane gas on earth on the loose. No more, no less. You can have methane in a room, and no fire. You can even have some sparks...though one is bound to catch. The explosion would be just as harsh as if you put the same amount of methane to oxygen ratio in a room here. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

newtonian · Jan 24, 2005

BS2TAA- Hi! You are correct that earth's atmosphere is fine tuned for earth's awesome and unique ecology. I will research your numbers, but you are essentially correct. However, like Vogon, I don't believe this is luck. Unlike Vogon, I don't believe in macro-evolution, but rather in Divine creation. Therefore, I thank Jehovah that he has made earth so pleasant for human living. I am also sad at how man is destroying the environment- which is also testimony to how fine tuned our ecology is. I will post again on those numbers-ratios.

vogon13 · Jan 24, 2005

Voyager showed atmosphere 98% nitrogen. Tough getting enough methane molecules in one place for a fire or explosion. Expect Huygens to refine figures little. In earth atmosphere, I seem to recall, even gaseous hydrogen is safe at concentrations under 3%. Percentage of methane in Titan atmosphere similar to concentration of wator vapor on earth. Titan atmosphere has much more argon than methane. Puddles of methane on ground a different matter, provide oxidizer and ignition source and fire will burn until fuel and/or oxidizer depletion. Or Titanian equivalent of fire department arrives. <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

newtonian · Jan 24, 2005

Saiph - Hi also! How are you? Well, I don't agree, simply because of temperature difference. Temperature influences chemical reactions, including rates. Often there is a slow rate which changes dramatically to an explosive rate at what is called the kindling (sp?) point. I don't know what the kindling point of methane is, but I feel quite certain it is way higher than the temperature on Titan, which is about 93-95 degrees Kelvin- that is very cold indeed! Also, Nitrogen serves to reduce the risk of fire on earth. Nitrogen is also a major constituent of Titan's atmosphere- and this would tend towards your post of the similarity of Titan and Earth as respects methane danger. Also, are the minerals on Titan oxidized? I doubt it, since earth is rather unique as having Oxygen as the most abundant element in its crust. If not, then Oxygen would tend to combine gradually with non-oxidized minerals on Titan. Of course, water is oxidized hydrogen, and water is present on Titan. Now, I await your response to fine tune (intelligent) my off-the-top-of-my-head appraisal. Thank you, btw, for your many informative posts.

newtonian · Jan 24, 2005

vogon13 - Sorry, I didn't see your last post. I agree, though I am not sure of the numbers. However, concerning your earlier post on luck vs. evolution: How do you propose evolution started life on earth? I agree microevolution is influenced by the environment and natural selection. However, there are observed genetic limits that make your suggestion of macro-evolution untenable - to me. Feel free to post some scenario as to how we ended up with the delicate balance we have - such as why plants did not use up CO2 before animals replenished it, etc. I have seen many scenarios, but none of those I've studied hold water (pun intended). Therefore, I give credit to Jehovah for his gift to man: our beautiful earth.

spaceman186000mps · Jan 24, 2005

This is very interesting indeed. Now my question is this. With what is know about titans present atmosphere,... How would liquid oxygen or lox burning rocket descent engines react, with the titan atmosphere during a heavy probe landing attempt ? Also I realize that parachuting in is very practical , but I also realize that it would take rocket engine to depart the surface. Then, my feeble mind races in thought to questions like, would helicopter type vehicles fly in titans atmosphere, or would gasoline all terrain vehicles run on the surface if their carburetors were properly mixed? I'm here to learn, Help me out . Thanks <div class="Discussion_UserSignature"> 70 percent of novel proceeds www.trafford.com/06-1593 are donated to www.caringbridge.org </div>

vogon13 · Jan 24, 2005

Dense atmosphere begs for glider type reentry vehicle to recon surface on way down. If in your scenario, rocket engine fuel mixture ratio off far enough to allow large amount of unburned oxidizer in exhaust your landing is in dire trouble before you ignite CH4 puddles on ground. Shuttle main engines for example, always operate too rich. H2 light to carry and surplus H2 in combustion cycle keeps engine innards from oxidizing. Shuttle engine only varies O2 amount for throttling, H2 always at full blast thru turbopump. Loss of H2 prior to loss of O2 in Challenger accident severely damaged engines (not that this played any role in loss of vehicle, consequential effect of SRB leak burning hole in LH2 tank) . <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

Saiph · Jan 24, 2005

Newtonian: The temperature would indeed effect the reaction rate. E.g. if the temperature is hot enough, no spark (a source of heat) is needed. And the hotter it is, the faster the reaction. However, temperature aside, there is no difference. spaceman: IIRC an efficient rocket engine should leave no LOX un-used in the exhaust fumes. As such there wouldn't be much of an effect. But imagine a gas torch on earth, where the gas is shoved into the atmosphere, and through a hot region (the previously burned gas)...it would react in just such a way. Methane reacts with oxygen, oxygen reacts with methane. All you've changed here is which one is in the tank, and thus the limiting reagent (when the tank runs dry, the reaction is over). <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

bs2taa · Jan 24, 2005

When I was talking about striking a match, of course I was joking. But you'd think with the abundance of flammable gases on the planet that something is bound to give. You say that we evolved into being compatiple with these gases? It's a good theory, but you also have to remember that when life first started, it would either adapt or not. If life cannot breathe whats already on the planet, then that's it right? There would be no second chances correct? I see where your coming from and it's a good possibility. The only way if this is possible is if there were micro organisms that didn't breathe oxygen. I'm not sure if there are because I'm not to big on biology. If there were, then the microorganisms would evolve into an organism that could breathe the air. And if it didn't live, it would probably have to start all over again until it has the ability to breathe the earths natural gases. But then we also have to think, Earths atmosphere has changed over the times. Maybe I'm making no sense at all. <img src="/images/icons/frown.gif" />

newtonian · Jan 29, 2005

BS2TAA- A little biology is necessary to understand what is involved in this tangent: Plants breathe carbon dioxide (CO2) during the day, some oxgen at night. There are micro-organisms that use other compounds, such as sulphur. There are micro-organisms that exist in extreme environments, called appropriately: extremophiles. Now, you are correct that the environment required to create life might not sustain life. This is one of the main problems with chemical evolution scenarios for the origin of life, For example, UV radiation can cause complex polymers but it can also destroy other complex polymers. I should ask first if you understand chemistry, because if you don't I will simplify and explain. Getting back to Titan, oxygen would destroy many building blocks of life, yet water is necessary for life. Water is H2O, i.e. it contains oxygen! And energy required to drive origin of life chemical pathways can also release oxygen from water by a process called photolysis (also electrolysis), or photo-dissociation. In fact, since water is on Titan, it would be a likely source of oxygen by this type of reaction. Besides that, water also reacts with many chemicals on potential chemcal pathways to necessary building blocks of life. As an example, amino acids are necessary for life, specifically, for example, proteins. Chemical pathways for different amino acids require different environments: hot, cold, wet, dry (some even requiring condensing agents), acid, alkaline, etc.. Zeroing in on dry: like oxygen, water reacts with many chemicals on pathways to amino acids from basis molecules like hydrogen cyanide (HCN). HCN + H2O often yields formic acid. Water also reacts with other chemicals on pathways to amino acids. Those who theorize about origin of life on Titan, for example, usually ignore the basic chemistry required for the origin of li

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