Expert: Dr. Henry Boyter, Jr. - 3/5/2007

Question
A few days back i asked


"I heard this in a movie ("The Fantastic Four") and got curious.

With a high enough temperature, is it possible to ignite ALL OF the earth's
atmosphere ;thereby destroying it?"

I think you misinterpreted my ques. What i really meant was this:

Consider a sealed room having 70% methane and 30% oxygen.
If i was to light a matchstick at one corner of the room,the whole room ,NOT just the corner would catch fire.
Similarly, if at some corner of earth on open ground ,if a high enough temp. was attained would the nitrogen and oxygen catch fire.And as the whole earth atmosphere is mainly N2 and O2 , would this fire engulf ALL the O2 and N2 of our planet?  

Answer
Let me try this a different way because you are comparing apples to baseballs.

1. Your methane/oxygen example works because methane ignites at temperatures that can be achieved.  Methane chemically wants to react, nitrogen would be one of the hardest things known to ignite.

2. The world is not a box, but lets use that as an example.  If you took a box with N2 and O2 and sparked it as you raised the temperature, the oxygen would react with itself and the box before it ever reacted with the nitrogen.  If you only sparked it at the N2/O2 ignition temp, just the heat would react the oxygen with itself and the box and the box would melt, before you ever got to that temp.

3. Now the earth is not a box.  If you raised the temperature of the earth to the N2/O2 reaction temp, the world would be engulfed by everything catching on fire, long before you ever had a chance to spark it.

Now if you want to talk science fiction, where the temperature could be raised instantly without any of this other stuff happening AND you had spark sources all over the world (don't forget it will be raining someplace), I can't disprove it would happen, but I can say, it will not happen within the confines of actual chemistry and physics.  We also haven't talked about the fact that unlike a box, the world is not a closed system.  If you are a bad guy, just raise the temp and the world would be engulfed and destroyed, no need to spark the N2.