Speaker: Wenjaun Fang (UM Physics)
The expansion rate of the universe is undergoing an acceleration at the current stage of its evolution history. Instead of signifying the existence of a missing energy component with negative pressure--the dark energy, this phenomenon may indicate new behaviors of gravity arise on the cosmological scales, where we have not explored before. The Dvali-Gabadadze-Porrati model provides an explicit example to address the accelarated expansion of the universe purely from the perspective of gravity, without introducing any from of dark energy. As an illustration of how theories of gravity can be tested over cosmological scales, Professor Fang will talk about observational probes of this model--can it fit both measurements of the Universe's geometry and the growth of its structure simutaneously? Throughout the talk, Professor Fang will focus on a comparison of this model with the concordance\LambdaCDM model.