Bifalgorithm post

The Big Bang didn't make a single atom of calcium in your bones or iron in your blood. So where did they actually come from? When the universe started with the Big Bang, it made almost nothing except for hydrogen and helium, the two lightest elements there are. For hundreds of millions of years, the universe was basically just gas drifting in the dark. Then that gas pulled itself together and lit up into the first star. A star is basically a furnace. In its core, it's fusing those light elements into heavier elements, hydrogen into helium, helium into carbon and oxygen, slowly climbing up the periodic table until it gets to iron. Iron is where it hits a wall because iron is just about the most stable nucleus there is. Fusing anything past iron actually costs energy instead of releasing it. So this furnace stalls out. That's the beginning of the end for the star. With nothing left to burn, there's nothing holding the star up against its own gravity. So the core collapses in about a second, and the whole thing rebounds into what's called a supernova, one of the most violent events in the universe. This explosion is so extreme that it forges every element heavier than iron in the explosion itself.The gold in your ring, the silver in your phone, none of that came from the star itself, but rather it was made in the death of one. And all of that gets thrown out across the galaxy where it drifts for millions and millions of years and folds into fresh new clouds of gas and eventually collapsing into new stars and a new world. If you follow it all the way back, the calcium in your teeth and the oxygen that's filling your lungs right now were forged in the death of a star that lived and died for billions of years before our sun was even formed. You're not like stardust. You are stardust. The next time you look up at the night sky, you're not staring at something far away or separate from you. You're looking back at where you began. The same stars that made the iron in your blood made the eyes that you're seeing them with. Follow along for more.

The Big Bang didn't make a single atom of calcium in your bones or iron in your blood. So where did they actually come from? When the universe started with the…