Electrons are as 'small' as anything we know of, showing no behavior that indicates some sort of structure with a size. We say they are 'point-like'. There are lots of other point-like particles: photons, gluons, quarks, muons, ....
I'm not sure what it would mean to say electrons are "just condenced energy smushed together until it becomes solid matter and mass." Energy and mass are just the same thing, measured in different units (E=mc2
) and called different names. So it doesn't make sense to say that energy is smushed together until it has mass. I also don't know in what sense an electron would be called solid matter. Solids are structured arrays of things where the pattern occupies some space, but electrons are point-like.
Here's what electrons are:
spin 1/2 in units of Plank's constant divided by 2 pi
a specific amount of rest mass-energy. ~ 9*10-28
a specific electric charge: ~ -4.8 * 10-10
esu or 1.60× 10-19 Coulombs
a property giving the strength and type of their participation in the 'weak interaction'.
They do not interact with the 'strong' nuclear force
They have no other traits that we know about. This list is sufficient to describe everything they've been known to do.
Maybe someday a deeper theory will be known and we'll be able to say that electrons, muons, etc. are specific patterns of behavior of some more fundamental (string?) constituents.
(published on 05/26/09)