  We present a new interpretation of dark energy in terms of an
\textit{Abnormally Weighting Energy} (AWE). This means that dark energy does
not couple to gravitation in the same way as ordinary matter, yielding a
violation of the weak and strong equivalence principles on cosmological scales.
The resulting cosmological mechanism accounts for the Hubble diagram of type Ia
supernovae in terms of both cosmic acceleration and variation of the
gravitational constant while still accounting for the present tests of general
relativity. This explanation allows to build dark energy models (i) without
violation of the strong energy condition $p<-\rho c^2/3$ (ii) with
non-negligible direct couplings to gravitation and (iii) natural convergence
mechanism toward general relativity.

Astrophysics