■ Robert Carter
FOR HE knows our frame; he remembers that we are dust. Psalm 103: 14
What are we made of? How ‘real’ is
the world? What does it mean to exist?
Have you ever wondered about
things like this? We humans like to ask
questions, but sometimes the answers
make us uncomfortable. Yes, we exist.
Yes, the world is real. But, the reality
of our reality is very, very strange. You
see, we are made of almost nothing.
Everything we see is mostly made up
of empty space. This is shocking when
you first realize it, but let me explain.
We and everything we can see are
made up of atoms. The atom is an
amazing thing. It has a dense centre
called a nucleus and a cloud of electrons
surrounding it. Inside the nucleus are
protons and neutrons. The nucleus
is held together by incredibly strong
forces that act at only short distances.
And since ‘opposite charges attract’,
the positively-charged protons in the
nucleus attract the negatively-charged
electrons that reside in a ‘cloud’
surrounding the nucleus.
How do we know this? The structure
of the atom has taken hundreds of years
and tens of thousands of experiments
to figure out. There is still much we
do not know, but scientists have developed an atomic theory that describes
everything we do know. They have also
made successful predictions, like the
existence of a particle called the Higgs
boson, the discovery of which made
international news. In fact, as of today
there is almost no evidence that atomic
theory is wrong.
Remember how short my time
is! For what vanity you have
created all the children of man!
Psalm 89: 47
But this is where things get strange,
even creepy. Our bodies are made up
mostly of oxygen (65% by mass), carbon
( 18.5%), and hydrogen ( 9.5%). Hydrogen
is the simplest element, and is well
studied, so let’s use it as an example.
What are the relative distances between
the nucleus and the electrons in the
hydrogen atom? What are the relative
distances between atoms in our bodies?
How much ‘empty space’ is inside us?
Since there is no well-defined edge
to the electron cloud, it is difficult to
determine the exact size of an atom. But
we can say that a hydrogen atom is about
100 picometres (pm) in diameter. That’s