Inhomogeneity-Induced Cosmic Acceleration in a Dust Universe

It is the common consensus that the expansion of a universe always slows down if the gravity provided by the energy sources therein is universally attractive. To examine this point we find counter-examples for the spherically symmetric dust fluid described by the Lemaitre-Tolman-Bondi solution. Thus, the validity of this naive consensus is indeed doubtful and the effects of inhomogeneities should be restudied. The example opens a new perspective for understanding the evolution of our universe