  We present a new model of dark energy which could explain the observed
accelerated expansion of our Universe. We show that a five-dimensional
Einstein-Yang-Mills theory defined in a flat Friedmann-Robertson-Walker
universe compactified on a circle possesses degenerate vacua in four
dimensions. The present Universe could be trapped in one of these degenerate
vacua. With the natural requirement that the size of the extra dimension could
be of the GUT scale or smaller, the energy density difference between the
degenerate vacua and the true ground state can provide us with just the right
amount of dark energy to account for the observed expansion rate of our
Universe.
