Where do our atoms come from? (opens in new tab)

"The knowledge that the atoms that comprise life on earth - the atoms that make up the human body, are traceable to the crucibles that cooked light elements into heavy elements in their core under extreme temperatures and pressures. These stars- the high mass ones among them- went unstable in their later years- they collapsed and then exploded- scattering their enriched guts across the galaxy- guts made of carbon, nitrogen, oxygen, and all the fundamental ingredients of life itself. These ingredients become part of gas clouds that condense, collapse, form the next generation of solar systems- stars with orbiting planets. And those planets now have the ingredients for life itself. So that when I look up at the night sky, and I know that yes we are part of this universe, we are in this universe, but perhaps more important than both of those facts is that the universe is in us. When I reflect on that fact, I look up- many people feel small, cause their small and the universe is big. But I feel big because my atoms came from those stars."

Where does the world come from? And what is beyond the universe?

  > In turn, most rain comes from water evaporated from surface water

This is true over the whole Earth, but if you look only on land (which is what matters in this case) roughly 80% of rainfall comes from plant transpiration, not evaporation from open bodies of water.

https://www.nature.com/articles/nature11983

So if plants are roughly half carbon half water, and the carbon comes from the air while the water comes from the ground, it makes sense that plants spread roughly symmetrically both below the ground and above the ground. Well, a bit more above the ground because they also need photons.

The elemental atoms ultimately came from the inside of the stars.

Hydrogen was created shortly after the Big Bang when the universe had expanded far enough to cool down that protons and electrons could come together to form hydrogens.

Hydrogens come together later to form the stars. Nuclear fusion inside the stars starts due to the pressure from gravity. Nuclear fusion of hydrogens turns them into heliums.

When the hydrogens at the core of the star are used up, the star collapses and then explodes, throwing the upper crust off.

At the core nuclear fusion of heliums starts, forming lithiums. Nuclear fusion of lithium then forms beryllium. The cycles of nuclear fusion of each element type continue to create the heavier and heavier elements. Carbons are created among the way. So is oxygen.

During each cycle the star explodes and throws off the elements from the upper crust.

After iron is created, nuclear fusion stops. Iron is super stable to resist nuclear fusion. Gravity continues to collapse the star until super nova happens.

Super nova is when all the other heavier elements created. Gold, silver, lead, platinum, uranium and others are created during this explosion.

The elements come together to form the planets and eventually become part of us. So we were created long ago inside a star.

"To throw around some numbers: about 220 petagrams (gigatonnes) of carbon dioxide will be released into the atmosphere this year; around 3% from burning fossil fuels; 44% from the ocean surface; and 53% from the land"

Does the 3% from burning fossil fuels seem too low? I thought that this would make up the majority of carbon dioxide released into the atmosphere every year

Fascinating and well written. I wish the author's site had an rss feed.

We're mostly made of the water our mothers drank before and during pregnancy. So I'm mostly made of coffee then.

The cosmos is within us. We are made of star-stuff.

Carl Sagan.

Most interesting parts of this article for me: most of the organisms weight in carbon and other atoms comes from and get recycled into the air, and, most atoms in our body replace every few weeks, we are just "patterns surviving through time".

This seems to be a very big difference with non-organic things, including computers, which even though they are coming pretty close to thinking with LLMs now, keep the same atoms in the same configuration all the time.

This was a fascinating read. One other interesting fact about the carbon in our bodies is that the sort of diet that a person eats over their lifetime can influence the ratio of the different isotopes of carbon in their body due to different plants preferentially using carbon 12 or carbon 13 during photosynthesis. You really are what you eat.

https://naturalhistory.si.edu/sites/default/files/media/file...

The post is mostly about earthly provenance, but also of interest: https://svs.gsfc.nasa.gov/13873/

What a fantastically written article! I was familiar with all of this (or almost all; I was not aware that fossil fuel burningakes up a measly 3% of yearly atmospheric carbon emissions) but there's a difference between knowing the information and seeing it explained so prosaically.

> In any case: to me, the picture this paints is one in which we are not so much solid, isolated objects; and more like patterns surviving through time.

Something I have struggled to find nearly as much material on is where our _molecules_ come from. I know of lots of ways in which they're formed, but things like, are there any molecules in stars? How much? How much are they distributed in the universe? How complex and large do molecules get in the universe?

I'm especially interested in the proto-life molecules. How close do we get to e.g. proteins without having life?

> about half your nitrogen atoms were being stripped from the air in some great metallic reactor like the one pictured

I’d never appreciated before how much nitrogen was taken from the air to support agriculture. I wonder if this has a direct impact on climate change. Does reducing nitrogen in the air necessarily increase the proportion of the other gases including carbon dioxide?

That is fascinating reading. It is not so easy to read, but it is fantastic. The Video animation is a hammer!

This resonated:

for effectively everyone who has ever lived, and even most living adults, your body contains at least one atom that has been part of them, such as air they breathed or water they drank.

We come out from the stars, and into the stars we shall return.

I'm pretty sure the future me is partly in this here ham sandwich.

It's not rocket science.