Where have all the atoms that constitute “you” been since the creation of the Earth?
“All of the atoms that make up your body were once parts of stars – the phrase “we are stardust” is not just poetic fancy. After that, they were part of the sterile planet (later to be called Earth) for some billions of years, and when life appeared, bits that were later to become “us”, began to be parts of the early forms of life on Earth – bacterial, plant, animal, fungal etc – all of it sharing atoms, especially carbon, oxygen and hydrogen atoms.
By a statistical certainty, many of the 7 billion trillion atoms that make up your body will have formed parts of many other organisms in the far past. Some of them have formed parts of living beings (plant and animal) in the recent past – you ate them. But some of those beings will be humans, still alive and sharing the planet with you as you read this; if by no other route than by the fact that the air others breathe out is the air you breathe in. The blood in your veins is red because of oxygen that was someone else’s last month, and will be someone else’s again next.
You may feel that your “self” is a solid, unchanging entity, but the matter which houses that self is a boiling mass, coming and going all the time.”
Contribution from Francis Blake, London N17 to “Note & Queries” in today’s “Guardian” newspaper.