Look at your wrist, see the blueish veins? The blood flowing through them contains hemoglobin, a protein that has four iron atoms incorporated into its structure. Iron is only naturally produced in one place, it can only be forged in the core of dying stars.
Every time you look at your veins, remember that you are built from, and kept alive by, pieces of stardust.
This is actually a thing, to the very best of my knowledge! Iron might not be only produced in the heart of a star on its way to going supernova (I would need someone with, y’know, actual degrees to say that for certain), but that’s certainly a major source! The way stars work is through fusion, or taking two atoms of an element (or different element) in an environment of massive heat and pressure and joining them to create a new element. Fusion gives off massively more energy than fission, which we’re more familiar with and can actually do ourselves with elements like uranium, but the hiccup in fusion is that there’s a point at which the energy gain is no longer high enough to offset the density of the atom created. So, fusion works GREAT on things like hydrogen or helium, which are both very small and therefore easily fused to give massive energy yields–this is why the biggest stars tend to burn very hot (not an absolute rule), because they have so much of these smaller elements available. These enormous stars–the sort of stars that die with a bang (nova/supernova) rather than a whimper (petering out)–burn hot and build up enormous pressure in their core, so the deeper you go the bigger the elements are.
Iron is the turning point, the point where you stop getting energy from fission and start getting it from fusion instead. As you work up toward iron from hydrogen on the periodic table, you get less and less energy from fusion, and as you get further from iron, into the higher numbers, you get steadily more energy from fission until you reach what we recognize as the radioactive elements, which break up easily enough to be practically applied for energy gain. Iron, however, is basically neutral: it won’t give energy either way, and managing either one would require a massive energy output. So, suppose you have a really huge star, a giant of some kind, and it’s been burning away happily for time immemorial (I don’t really have the time to go get data for star lifespans, I’m supposed to be studying for my organic chemistry final), fusing hydrogen into helium and helium into lithium and so on and so forth. And now it’s reaching the end of its life and the elements it’s creating are getting up to the teens and twenties, and it fuses two oxygens into an iron atom. That’s the cutoff: the star has now started to die. The dense iron building up at the core of the star causes it to collapse inward, building pressure, and when the pressure inside gets too much…boom. Supernova.
So yeah. Iron is the element that kills stars, and it’s the element that keeps us alive. It’s…it’s pretty damn cool.
