The Last Two Forces
For distances much larger than the size of an atomic nucleus,
the remaining two forces have
only tiny effects- so we never notice them in everyday life.
But we depend on them for the
existence of the stuff from which the world is made,
and for the decay processes that make
some types of matter unstable.
They impact the smallest objects in the universe and the largest.
We thank the Berkeley "Center for Particle Astrophysics"
for the use of their dark matter images.