DarrinBrunner@lemmy.world 1 day ago
I’m answering in hopes that someone else who knows more will answer.
I think, no. Just because if you look at a small flame, like a candle, it isn’t the same as a campfire. An ant-sized fire would be, supposedly, like a much smaller candle flame, but it’s hard to imagine such a thing. I’ve never seen such a small flame, I think they can’t exist. Why? I don’t know. Imagine a spark from a fire, which would be about the size of an ant fire. It burns out quickly because there’s so little fuel. It’s a small amount to us, but not to an ant, but it would still burn out just as quickly. So, there must be some lower physical limit to fires acting like fires as we experience them at our scale. Bigger fires also behave differently to smaller fires. They’re more violent, and “create their own weather”, like you hear when there are forest fires.
There is a theory that if alien life exists, those organisms will be roughly our size. The reasoning is that you can’t achieve advanced civilisation without fire, and you can’t tend a fire if you’re much smaller or larger than a human.
Not my theory, but an interesting thing to consider
I’ve never heard that before! It’s interesting.
I think it depends a ton on environmental conditions. Could combustion on planets with different gravity and pressure take place at different scales?
Fire is a thermodynamics problem, so it relates to area and volume, not gravity.
Gravity does impact creature size, however. A lower-gravity environment supports larger creatures, higher forces creatures to go smaller. Thought is a chemical process though, so that would have a minimum size as well.
Smaller I suppose, but larger? Why not? Wouldn’t you just have a really large fire?
Bigger fires burn out quicker cause they burn hotter.
But maybe you wouldn’t need as much fire cause bigger animals tend to hold heat better?
Curious what the actual research reasoning would be.
But maybe you wouldn’t need as much fire cause bigger animals tend to hold heat better?
I thought the same thing. Then again, fire is not only needed for heat, but also for cooking food and creating new materials (metallurgy essentially). But surely a large creature could just make fires the same size as humans do if they needed to do those things? But perhaps it’d be impractical to cook food at a tiny fire hehe
I don’t know specifically about fire but I think the square-cube law plays a significant factor in the idea that alien life would be similar in scale to humans.
Yea probably within an order of magnitude or so - then again, elephants are probably within an order of magnitude of size of humans. I don’t see why elephants couldn’t eventually evolve to an intelligent civilisation, given enough time. I’d say that’s still pretty large.
But yea I mean the blue whale and the largest dinosaurs are probably about the limit of how large life can get, at least with Earth conditions.
I find that theory fascinating, as well as the one where it would have to be carbon based like us because chemistry.
Then intelligent life would need to be land based because you can’t easily do things requiring heat without an oxygen atmosphere and something to burn
To be space faring, your planet couldn’t have much more gravity than earth, else chemical rockets wouldn’t work
At what point is it usefully generalizing on what life would need vs where are preconceptions limiting your thinking?
What about using heat from geothermal vents?
Thermal vents under water will keep you alive but it won’t be your energy source for industry. Also, how do you invent the steam engine under water on a thermal vent that cannot move around?
Too much oxygen. A tiny little campfire would be like a massive, and very short lived inferno to the “ant” that built it, because the ratio of oxygen to fuel is perfect for human size creatures but way too high to sustain a tiny fire for a long time.
SorteKanin@feddit.dk 1 day ago
Your intuition is correct and it’s quite simple really. A small fire cools down faster than it can keep/generate its own heat.
Surface area of the fire (which correlates with how quickly it cools) grows with the square of the size of the fire. Meanwhile volume of the fire (which correlates to how much heat it generates, how much fuel it is burning) grows with the cube.
At small sizes, the surface area can win out against the volume. However, because it grows with the cube, the volume eventually wins as the fire gets bigger. So a fire can only get so small.
meco03211@lemmy.world 1 day ago
Kinda like the square cube law.
SorteKanin@feddit.dk 1 day ago
Not kinda, exactly like it - it is just another example of it :)
Leviathan@fedinsfw.app 11 hours ago
What about alternate fuels?
SorteKanin@feddit.dk 11 hours ago
Considering coal is pure C, I can’t really imagine an alternate fuel that would change the math substantially