Sgt. Brainiac's Brain Busters
Research Papers for the Armchair Nerd
Sgt. Brainiac's Brain Busters
Research Papers for the Armchair Nerd
Published On: 2/19/2024
I've never really liked Thanos. Questions of morality aside,[1]The great part about science is I can say things like "questions of morality aside" as if that isn't a completely unhinged thing to say. his plan betrays a total lack of understanding of population dynamics. The premise that we could restore our resources by simply halving the population is absurd; populations don't work like that. Any population would grow back pretty quickly, especially now that half of its competition for resources is up and gone. If we wanted to be mathematically rigorous,[2]And let's be real, who doesn't want to be mathematically rigorous?! we could use the logistic equation to solve for how long it would take for the human population to replenish itself. Or we can go the lazy[3]read: boring route and simply look at historical trends for human population. We very recently hit 8 billion humans living simultaneously[4]If you don't count zombies. and Worldometer[5]It's cited by Wikipedia, it's gotta be right![6]I'm achieving a tooltip ratio of ~1 tooltip per 10 non-tooltip words, are you tired yet? says that our population hit 4 billion in 1974. So it takes about 50 years for the human population to double. Is Thanos going to do another snap in 2074 to keep the population down? No, he's not:
Read a (comic) book.
Now I hear you saying: but Sgt. Brainiac, wouldn't half of the world's population disappearing be inherently traumatic and probably slow the birth rate considerable? Sure, fine, whatever. But with advances in medicine since 1974 I don't think humanity will have a hard time repeating its population growth. Unless Thanos triggers some kind of apocalyptic event[7]Foreshadowing.[8]I promise not to do the "Foreshadowing" bit in every blog post...maybe.... that prevents population growth or kills much more than half the population, it's not gonna take significantly longer than 50 years to end up right back in the same boat.
I also feel compelled to point out that the universe is a big place.[9]Citation needed. Earth only contains 10^25 kilograms of matter. The universe on the other hand, according to our best estimates, weighs 10^53 kilograms.[10]This only includes ordinary matter, as opposed to dark matter and dark energy. But I feel comfortable excluding them because I don't really like the taste of dark energy sandwiches.
$$M_{Universe} \sim 10^{53}\ kilograms \cdot \frac{1\ Earth}{10^{28}\ kilograms}$$$$\sim 10^{25}\ Earths$$
Sure, not all of that matter is immediately useful, but if we can't turn 10 yottaEarths into enough resources to support all life in the universe (considering at the moment we only know about ours on Earth and maybe some microbes on some asteroids), I think we have bigger problems as a species.
But my real problem with Thanos—aside from the morality, aside from the population dynamics, aside from the plethora[11]To quote the inimitable El Guapo: "I would not like to think that a person would tell someone he has a plethora, and then find out that that person has no idea what it means to have a plethora." of resources in the universe—is his failure to understand the concept of the law of conservation of mass.
The principle of conservation of mass is very nearly self-explanatory. Simply, the total amount of mass cannot change, that is mass cannot be destroyed or created. If little Johnny has three particles and gives two to Jayney, then he may now only have one particle, but there are still three particles in total. If I have a bundle of 1023 carbon atoms, no matter if I get rid of some of my atoms or if I add some other atoms to my bundle, the original 1023 will exist, and I could hunt them down and separate them back out if I wanted to, though I would need a very small pair of tweezers.[12]And those tweezers would need to be made out of lasers. There is a slight caveat to this, but I'll get there in a second.
I mention carbon specifically because humans, and all other life on Earth, are made of carbon.[13]Carbon is literally where the "organic" in "organic chemistry" comes from. Based on this definition, I'd like to think that all food in a supermarket should be labelled "organic." Thanos snaps his fingers and we all cry as we watch Tom Holland—and his carbon atoms—disappear.[14]Sorry, spoilers. But remember, the law of conservation of mass says that stuff can't just disappear, it has to go somewhere. But where does it go? In the film we actually watch it dissolve and float up presumably harmlessly into Earth's atmosphere.[15]Yes I realize that Spider-Man specifically was on Titan at the time, but nearly all other terrestrial life was on Earth at that moment. Touch some grass, you nerds. It's tough to know exactly what all that carbon will do (especially since it's wrapped up in a bunch of different molecules within the body and they will all behave differently floating around the atmosphere[16]The methane in the body, for example, is much worse for climate change than carbon dioxide on a per molecule basis.), but carbon dioxide has a quite negative enthalpy of formation, so in the absence of half of all photosynthesizing life, I think it's a good approximation to assume most of the carbon will pretty quickly end up as carbon dioxide, the main climate change driver. Now we get to the good part: math!
Some helpful people with too much time on their hands have done the work of cataloguing the entire biosphere and counting every carbon atom attached to a living being on Earth.[17]"Two trillion, three hundred and forty two million, three hundred and seventeen thousand, and two. Two trillion, three hundred and forty two million, three hundred and seventeen thousand, and three. Two trillion...."
"Hey Sara, can you hand me my mug?"
"Sure dude...shoot, I lost count...." They found that all the living organisms contain roughly 550 Gigatons of Carbon (Gt C). Subtract out Spider-Man's contribution and half that, and you find the amount of carbon released into the atmosphere.
$$C_{Released} = \frac{C_{Biosphere} - C_{Spider-Man}}{2}$$$$\approx225\;Gt\;C$$
Some other helpful people over at a US Department of Energy branch devoted to CO2 analysis have found another useful number relating the tons of carbon released into the atmosphere and the corresponding increase in the percentage of atmosphere that is carbon. Typically this number is given in Gt C per ppm by volume of atmosphere CO2, where ppm is parts per million and would be 0.0001% of the total atmosphere. That number is 2.13 Gt C per ppm. So solving for the increase in atmosphere carbonness[18]Definitely a word is fairly simple:
$$\Delta CO_{2} = \frac{C_{Released}}{Gt\;C\;per\;ppm}$$$$=\frac{225\;Gt\;C}{2.13\;Gt\;C/ppm}$$$$=105.6\;ppm$$
That doesn't seem that bad, that's only an absolute increase in Carbon by volume of 0.01%!
The helpful people over at those small start-ups NASA and NOAA have catalogued the ppm CO2 in the atmosphere for the past several decades through fancy devices and satellites. And other amazing researchers have measured CO2 centuries back by drilling out long tubes of ice near the poles of Earth and counting the carbon with neat methods like a dry extraction “cheese grater” and cryogenic trapping technique.[19]I hear about things like this and think that I might be in the wrong line of work. They put it all together into this super useful graph:
And here's where we start noticing some concerning things. Namely that the current level as of this writing is only 423 ppm and that there has been a roughly 100 ppm increase since around the 1950s, right around the time the post-war rampant consumerism really got into the swing of things.[20]You know, the thing that kinda got us in the climate change boat in the first place. This means that not only did Thanos' snap cause a near instantaneous 25% relative increase in Carbon in the atmosphere, but that it would also be responsible for roughly 40% of all man-(or titan-)made emissions. Here, let me redraw that graph with the predicted result of the Thanos snap:
Equilibrium Climate Sensitivity (ECS) is a measure that climate scientists use to try and predict the effect of increasing CO2 on the climate. Specifically ECS is a prediction of the rise in global average temperature if the ppm CO2 in the atmosphere rises to double its preindustrial levels.[21]There is another model, the Transient Climate Response (TCR), but it inherently assumes a slow but steady increase in CO2 concentration, which is not the case with our little Thanos kerfuffle. This will almost be true after Thanos does his little publicity stunt[22]All press is good press, right? as our preindustrial level is 270 ppm and Thanos will put us at 525 ppm. Regardless of author, the ECS is three degrees Celcius or higher at the time of carbon doubling. Two degrees is generally the accepted cutoff for inevitable climate issues beyond a continued streak of the hottest years on record. We—and by we I mean mostly marginalized and underserved communities—are already dealing with increased mortality and lower quality of life because of climate change.[23]Like this and this and this and this and.... It's hardly a stretch to assume that such a drastic increase in ppm CO2 would result in a >2 degree change and would not be pretty.[24]And if we're seriously unlucky (this isn't really possible, but neither is releasing half of the biosphere's carbon in an instant), we could trigger a runaway greenhouse gas effect. You never hear about anybody visiting Venus, and that's the reason. Well that, and the absurd price of rocket fuel nowadays.
I mentioned a caveat to the conservation of mass earlier. Technically, it's the conservation of mass and energy. Individual particles can be created or destroyed, as long as there is a respective destruction or creation of energy. This is actually what Einstein's \(E=mc^2\) tells us: the specific ratio of energy (E) created to mass (m) destroyed or vice versa is the speed of light (c) squared, and it's what allows nuclear reactions to work. So you might have noticed that we can get around releasing all that carbon into the atmosphere as long as it is converted into energy. Sure, let's calculate that energy:
$$E=mc^2$$$$=225\;Gt \cdot (3.0 * 10^8\;m/s)^2$$$$=225\;Tkg \cdot 9.0*10^{16}\;m^2/s^2$$$$=7.75 \cdot 10^{27}\;Joules$$
Gee wilikers mister, the speed of light is a big number, and the speed of light squared is even bigger. And that means the energy released by converting all that carbon[25]Keep in mind that life on Earth is (at least Humans are, according to this fun palette-cleansing article) roughly 18.5% carbon by mass, so the resulting energy release if all matter—carbon and otherwise—were converted would be 5.4 times as large. would be 8 ronnajoules. Ronnajoules is a unit we don't often see in our day-to-day interactions,[26]Some people don't even use joules day-to-day, but I try not to think about those people. let me go look up roughly what that number means...and that's the energy in 10 trillion Tsar Bombas, the largest atomic bomb. In fact, the carbon in an individual human (to say nothing of all the other life on Earth) would be equivalent to roughly 4 atomic bombs each. Needless to say, we don't see a cataclysmic explosion as each person disappears, so I think it's safe to say the carbon is released into the atmosphere. Though in comparison to the worst possible climatological impacts, a so-instaneous-that-no-one-knows-what-happens apocalypse might not be so bad.
Anyway, climate is tricky. We're very sure climate change is real and problematic and that humans are causing it. More sure than we are that smoking is a harmful activity. But to predict any specific climate changes[27]What's the average strength of a hurricane created by a butterfly as the global temperature rises? is difficult. It's impossible to say what exactly all that extra carbon will do in the atmosphere, but when mixed with a loss of half of our carbon-eating plants, I'm not very hopeful that the remaining 50% of humanity is going to have an easy time. Talk about unintended side effects.
All of this to say: if you're going to see your evil plan to fruition, maybe take a second to think about how it will impact the planet. Oh, and maybe try to eat local. The baby seals will thank you.