visualizing explosions on Mars with fire-retarding C02

[bonzelite]

how can a fiery explosion be possible in the Martian C02 enviroment, as such a gas is used in fire extinguishers? is there, then, a way for fire to burn in the non-combustable C02? or would there be a fiery explosion anyway? i assume there would be a glow, an ionized plasma glow, but not actual balls of fire, right?

 

[nexium]

Magnesium and some of the other light metals will burn in carbon dioxide releasing the carbon as clouds of soot. Six millibars, however, is likely too little pressure to support combustion.<br />Micrometeorites hitting Mars at perhaps 27 kilometers/second release large amounts of energy, producing a fireball something like an Hbomb which looks like a fire from a long distance away. Neil

 

[vogon13]

A conventional garage mechanic type acetylene torch would work just fine on Mars.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[bonzelite]

<font color="yellow">Micrometeorites hitting Mars at perhaps 27 kilometers/second release large amounts of energy, producing a fireball something like an Hbomb which looks like a fire from a long distance away.</font><br /><br />neil, please explain. what would the fireball be made of if the C02 puts fire out? are you saying it would burn if the meteorite were largely magnesium? i'm assuming a meteor would ionize the martian atmosphere, but would the impact create only an "ionized ball" rather than a "fire ball?" for example, animations of probes with aeroshells depict a firey entry. but would this look really like that, orange and burning? or would it really be blue or green glowing ionized C02 --non-combusting, but yet ionized. this is messing with my head because it seems like a paradox. ionization is not the same as burning, or is it? fire as we know it is a plasma. but plasma is not necessarily always a fire. <br /><br />and vogon, acetylene will combust in C02? what else will? and why is acetylene immune to C02? <br /><br /><br /><br />

 

[centsworth_II]

I imagine that any explosive contains its own source of oxygen. An explosion is so rapid that I don't think it could use the unconcentrated oxygen in the air, it wouldn't be an explosion, just a fizzle, if it tried to. So I think that an explosive, once set off, will blow up no matter what the oxygen content is in the air around it. The CO2 would stop any post explosion fires though.<br /><br /> <div class="Discussion_UserSignature"> </div>

 

[silylene old]

Here are some criteria to judge whether something is an explosion:<br />- Explosions require a very rapid combustion of a substance using its own oxygen supply. Initiated by ignition.<br />- Explosions causes a sudden increase in volume and release of energy in a violent manner, usually with the generation of high temperatures and the release of gases.<br />- An explosion causes pressure waves in the local medium in which it occurs. Explosions are categorized as deflagrations if these waves are subsonic and detonations if they are supersonic (shock waves). <br /><br />Impacts are not "explosions". <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[bonzelite]

ok. let me rephrase the premise: an explosion will create a wave-front that will propagate. if you drop a bomb on mars, it will explode and create a propagating concusion. but what would it look like? if it lacked fire, then would it only be observed as a billowing dust cloud? or would it not explode at all, needing oxygen to ignite? <br /><br />furthermore, what if the bomb were self-contained and did not need oxygen to explode, like a nuclear bomb? even in that case, there would be no observable fire storm. only the blast waves and airborne debris. <br /><br />there is a thread about an explosion observed on the moon. and there was a recorded flash. being there was no oxygen, this flash was not "fire." but was ionized and molten particulate matter. but this is basically fire. so what would that have looked like as observed from a few meters away? would we have seen this giant billowing cloud of fire? or a fireless ball of propagating molten debris? or was there actually a "fire" there? a glowing "plasma ball" as the molten debris ionized the surrounding releases of gas? the sun, for example, exists in the vacuum of space but is a gigantic sphere of glowing plasma. <br /><br />in other words, without oxygen, there cannot be fire. but there can be an ionization of particles, and there can be molten rock that glows. but the moon has no fire retarding C02. and Mars does. maybe i've been answering my own questions?

 

[silylene old]

There was no "explosion" on the moon. There was an impact, which for a brief time produced hot bright material and glowing plasma.<br /><br />Typical explosives include their own oxidizers, and don't rely on atmospheric O2. That's why explosives work in vacuum.<br /><br />Self-propagating explosions (for example, a fuel air explosion) require a substantial amount of available oxidizer (20% O2 in the atmosphere, for example).<br /><br /><font color="yellow">in other words, without oxygen, there cannot be fire. </font><br />Oxygen isn't the only gas which will support a self-propgating explosion. For example, fluorine gas (F2) will oxidize many materials very quickly and will support a self-propgating explosion. (Wood spontaneously burns in an inert atmosphere containing 20% F2.)<br /><br />Many of alkali metals are so easily oxidized that they will oxidize vigorously and maybe if they were powdered or sprayed as a liquid they perhaps could explode in a self-propagating reaction in the presence of suitable gaseous oxidizers . I can imagine water-vapor, H2, H2S, X2 (X=halide), O2 and maybe C) or CO2 could all serve as adequate oxidizing agents. <br /><br />Back to Mars - Perhaps if somehow liquid Cs was sprayed out into the atmosphere, and then ignited with a little bit of H2O, it could self-propagate and form an explosion front as it forms Cs2CO3. (I picked cesium because it is the most easily oxidized non-rare alkali metal) <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[vogon13]

I said an ordinary acetylene torch will work on Mars, not that C2H2 burns in CO2.<br /><br />Acetylene is in the orange tank. What you suppose is in the green one?<br /><br /><img src="/images/icons/wink.gif" /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[bonzelite]

oxygen, i'd bet.

 

[unlearningthemistakes]

<font color="yellow">is there, then, a way for fire to burn in the non-combustable C02?</font><br /><br />potasium also reacts violently without atmospheric O2 but water. as also potassium chlorate and sucrose(sugar).<br /> <div class="Discussion_UserSignature"> <p>pain is inevitable</p><p>suffering is optional </p> </div>

 

[bonzelite]

<font color="yellow">An atomic fireball is not burning as such. <br />But the thermal energy in it breaks down all mollicules into atoms which recombine as it cools. <br />Hence the look of a fireball.</font><br /><br />i never quite understood that process. thanks lots. that is very interesting, indeed. the fireball structure that we see is the recombining of the atoms that were broken down at the initial flash of impact or explosion. <br /><br />the rate at which, generally, a fireball would "decay" or fade would probably be much quicker on mars than earth. it would be there in a flash and maybe a second or two then disappear. it would not continue to billow out and burn as on earth. <br /><br />i'm trying in earnest to actually picture this in my mind. the nature of combustion on mars is quite different. i hear the prior post about the thermal energy. you have enough of that, then anything will burn. regardless of where it is. <br /><br />on mars, to get a prolonged fireball event that billows as on earth, with smoke and continual burning, would require, then, a measure of thermal energy several orders of magnitude higher than what would be required on earth. but you COULD plausibly have it.

 

[jatslo]

the energy release is related to fusion and/or fission

 

[unlearningthemistakes]

agreed. <img src="/images/icons/smile.gif" /> ( as in the Sun's process ) <div class="Discussion_UserSignature"> <p>pain is inevitable</p><p>suffering is optional </p> </div>

 

[nexium]

I think we were on the right track talking about plasma. Most of a small impactor and some of what it hits are heated far into plasma temperatures by the kinetic energy. The atoms emit light even if chemical reactions are negligible, so it looks like fire. As the fire ball expands it cools below plasma temperature and there after produces little or no light. Results should be much the same for Mars or the Moon or in the vacuum of space, even if the kinetic energy is supplimented by chemical reaction. On Earth's surface secondary fires prolong, and suppliment the effects. Carbon dioxide can also be heated to plasma temperatures. Neil