Every material thing is made of atoms. Even a small chunk of ‘thin air’ the size of a sugar cube will contain – at sea level and a temperature of zero degrees Celsius – around 45 billion billion atoms.
But of course each atom is tiny. Comparing one to a line that’s just a millimetre long is about the same as comparing a sheet of paper to the height of the Empire State Building. And if you wanted to see with your naked eye the atoms in a single drop of water, you’d have to somehow enlarge that drop until it was more than 14 miles across.
But even atoms, small as they are, are mostly empty space – the solidity we experience around us is an illusion. If an atom was the size of a cathedral, the nucleus would only be roughly the size of a fly in the middle.
Buzzing around the nucleus are a cloud of even tinier electrons. We know that these are negatively-charged. We also know that when you try to push the negative pole of one magnet against the negative pole of another, you face resistance because the one pole repels the other.
So when you sit in a chair, you are not actually sitting on it but instead levitating above it at a height of one angstrom (a hundred millionth of a centimetre) …. because your body’s electrons and those of the chair are implacably opposed to any closer intimacy.
Most of the atoms in our bodies came out of the Big Bang many billions of years ago.
All of the stars in the night sky were born from the same stuff … and when our bodies die they will one day become the fuel of future stars.
The cycles go deeper still. Carbon is the basis of life on Earth and nitrogen makes up 78% of our atmosphere. These elements were formed in stars, some of which blew off their outer layers to create vast clouds of ionised gas. As these clouds expanded across space, they enriched our Galaxy with carbon and nitrogen atoms … and some of these joined the clouds of gas and dust that eventually gave birth to the Sun and Earth.
Each of us today is partly made from these same atoms (along with those from the Big Bang). Along their way to becoming part of you, these atoms have almost certainly passed through several stars and been part of millions of living organisms.
Our bodies each contains vast numbers of atoms (around seven billion billion billion). These are so vigorously recycled when we die that a significant number – up to a billion for each of us it’s been suggested – probably came from Shakespeare’s body, and a billion more each from Cleopatra, the Buddha, Queen Elizabeth I, Ghengis Khan and so on.
From the Big Bang to stars, from stars to Shakespeare’s body, from his body to yours … and eventually from your body to future stars. That’s some journey.