  In this work we show that the presence of a vector field on cosmological
scales could explain the present phase of accelerated expansion of the
universe. The proposed theory contains no dimensional parameters nor potential
terms and does not require unnatural initial conditions in the early universe,
thus avoiding the so called cosmic coincidence problem. In addition, it fits
the data from high-redshift supernovae with excellent precision, making
definite predictions for cosmological parameters. Upcoming observations will be
able to clearly discriminate this model from standard cosmology with
cosmological constant.
