Oddbean new post about login | logout Fire can't exist without life. Even though there are water in several planets, fire is exclusive to earth (Sun is plasma). Let that sync in. GN.
Oxidation is corrosion; electrons moving from one molecule to the other, electricity, not exclusive to earth. 👍
Correct. But electricity is not fire. :)
The sun IS fire. There is no life on the sun.
Fire requires oxygen. Sun doesn't have oxygen.
No kidding, it is nuclear fusion and still fire.
Excuse me. It in fact is not combustion but a fusion fire burns at the heart of the sun. It is the source of life.
Well... Kind of. But that's because combustion requires an oxygen rich atmosphere. Life as we know it depends on oxygen but that doesn't mean fire requires life. We've found planets with O and C in their atmospheres so fire is definitively not exclusive to earth.
Which?
Agree, gotta reach at least 20% O to have an ignition via either abiotic or biotic means. Venus is a great example. Latest research points to both been a lot more rare than what we once thought. Very interesting distinction between life (no fire) and civilized life (barbecue 😎). Balbi, Amedeo, and Adam Frank. “The Oxygen Bottleneck for Technospheres.” arXiv preprint arXiv:2308.01160 (2023).
I recently learned of a very interesting (though almost certainly not true) theory that the early universe teemed with life because there was a brief (some number of the millions of years, I believe) period where the space of the universe itself was at standard temperature and pressure.
Found the video: https://www.youtube.com/watch?v=uTrFAY3LUNw I love this channel if you're interesting in astro physics, astronomy, cosmology, etc.
Isaac Arthur is a gem. Highly recommend.
One-click link to the paper: https://arxiv.org/pdf/2308.01160.pdf Very interesting, and a valid point. All technology (and all life) requires a metastable energy gradient, and combustion would have to be the easiest to bootstrap. Our technological toolkit is very dependent on oxygen combustion, an important engineering barrier to space resource development. The authors point out that paper cannot be ignited below 18.5% molar fraction of O2 at standard temperature and pressure. Not mentioned is that this proportion is largely independent of pressure, which is not intuitive at all (and why high-oxygen low-pressure spacecraft atmospheres are so dangerous e.g. Apollo 1). Also not mentioned is the importance of atmospheric nitrogen in supporting combustion. Combustion needs a fuel (reductant), an oxidiser, and heat, as most of you know. Nitrogen (78% of air by volume) is far more than a spectator - it has a low specific heat compared to most fuels (so it doesn't take away too much heat) but a low kinematic viscosity (so when it does gain heat it moves away violently, mixing fresh oxygen in close to the fuel). Nitrogen is also extremely inert chemically, so it doesn't interfere with the complex chain of reactions that comprise combustion. If Earth had a different buffer gas instead of so much nitrogen, combustion could be much more challenging, and require much higher proportions of oxygen for sustainment. CO2 has a much higher specific heat, and water vapor a higher viscosity. Chlorofluorocarbons are both, plus they break down and quench the free radicals on the fuel surface. I used to work with a guy whose doctorate was in combustion chemistry, next time I see him I'll annoy him with questions about this :-p
Woah thank you for this in depth analysis!
Thanks. Its adjacent to some stuff I've worked on, so I thought I'd share my 2c :)
Doesn't fire need oxygen and a fuel? Oxygen should be abundant enough, so is your point about the fuel? Isn't there any molecule that can satisfy this role? .. hmm.. if there is always a waste carbon molecule, I'd guess it requires a carbon-based material, i.e. more than a single molecule.
If you look at the conditions required for life, and the odds against them existing anywhere else, it makes the presence of life on Earth nothing short of miraculous.
Umm The sun? Other planets have volcanic activity. You are the same guy that thinks people don't want to see dick picks too. 🤭
magnetism shielding us is why there is life - this is why there is no life on the smaller planets of mars and venus it's complete nonsense that they used to have life, without protection from radiation DNA is destroyed and at best there might be bacteria in the soil far down below the surface where it's wet and stuff but it's true, without cells aggregating carbon into fibres there would not be fire very often once in a thousand years an oil spring would catch fire from a freak lightning strike on a very hot day
There is ten tonnes per square metre of matter shielding between each square metre of Earth's surface and the Karman Line. That is orders of magnitude more shielding against cosmic rays than even fragile complex slow-breeding critters like us require. Magnetospheric shielding is only directly important if you're in orbit. (It protects out upper atmosphere from erosion of light fractions by the solar wind, which is very important but a separate problem).
The fire triangle is an epiphany now?
I'll bite on this, nice idea! I zapped @Vitor Pamplona 5k on this note nostr:nevent1qqs0qe2x55j8urpfwrx7p2fnwgnlkjdky626dpxsfwyhk2kpcrjrjlqpzpmhxue69uhkummnw3ezuamfdejsygzxpsj7dqha57pjk5k37gkn6g4nzakewtmqmnwryyhd3jfwlpgxtspsgqqqqqqsac4au3
So how did the sun catch in the first place, without oxygen
Not sure but what about alkali metals + water? Nice chemical fire with no organic inputs.