  A kinematic method to access cosmic acceleration based exclusively on the
Sunyaev-Zel'dovich effect (SZE) and X-ray surface brightness data from galaxy
clusters is proposed. By using the SZE/X-ray data from 38 galaxy clusters
[Bonament et al., Astrop. J. 647, 25 (2006)], we find that the present Universe
is accelerating and that the transition from an earlier decelerating to a late
time accelerating regime occurred relatively recent. Such results are fully
independent on the validity of any metric gravity theory, the possible
matter-energy contents filling the Universe, as well as on the SNe type Ia
Hubble diagram from which the present acceleration was inferred. The ability of
the ongoing Planck satellite mission to obtain tighter constraints on the
expansion history through SZE/X-ray angular diameters is also discussed. Two
simple simulations of future Planck data suggest that such technique will be
competitive with supernova data besides being complementary to it.

Cosmology and Nongalactic Astrophysics