Matter is Mostly Empty Space
I understand that molecules are made up of atoms which are made
up of electrons, protons, and neutrons that are made up of gluons and
quarks. At each layer, there is considerable space. By the time
we get down to quarks, how much space is there -- perhaps 99.99999999999999999%?
A common misconception about matter at very small scales is that it is
either "solid" or "space". Instead, it is a combination of the two --
particles are not "little hard spheres", but instead are more like
'smears' around an atom. There is a probability function (a
mathematical way of describing the odds) describing the likelihood of
measuring a particle at a given location at a given time, but the
particle is actually spread across more than one place at a time. This
is one of the unusual aspects of quantum physics -- the traditional
"Newtonian" way of thinking about particles as "small, hard spheres
moving/orbiting around an atom" is not how the world appears to work.
So there is not really any "empty space" in an atom, just different
locations with different probabilities of finding a particle. To find
out more, do an Internet search for "wave-particle duality", and if
you want even more detail, "atomic orbital".
Hope this helps,
This is one of those issues that depends upon how you define "space" and
how you define "empty".
Particles at and below the molecular/atomic size, particles behave more like
waves, so that it becomes arbitrary how to say a particle "begins" and
"ends". Using the classical definitions of the size and the boundary of a
particle really no longer applies. So comparing electrons to marbles is not
a valid comparison.
Click here to return to the Physics Archives
Update: June 2012