  Dark energy models which alter the relative scaling behavior of dark energy
and matter could provide a natural solution to the cosmic coincidence problem -
why the densities of dark energy and dark matter are comparable today. A
generalized class of dark energy models is introduced which allows
non-canonical scaling of the ratio of dark matter and dark energy with the
Robertson-Walker scale factor a(t). Upcoming observations, such as a high
redshift supernova survey, application of the Alcock-Paczynski test to quasar
pairs, and cluster evolution, will strongly constrain the relative scaling of
dark matter and dark energy as well as the equation of state of the dark
energy. Thus, whether there actually is a coincidence problem, and the extent
of cosmic coincidence in the universe's recent past can be answered
observationally in the near future. Determining whether today is a special time
in the history of the universe will be a SNAP.

Astrophysics