  The Casimir energy density calculated for a spherical shell of radius equal
to the size of the Universe projected back to the Planck time is almost equal
to the present day critical density. Is it just a coincidence, or is it a
solution to the `cosmic dark energy' and the `cosmic coincidence' problems? The
correspondence is too close to be ignored as a coincidence, especially since
this solution fits the conceptual and numerical ideas about the dark energy,
and also answers why this energy is starting to dominate at the present era in
the evolution of the Universe.
