Coloquio DIFT David Weinberg

Speaker: Prof. David Weinberg, The Ohio State University, USA

Title: The Mystery of Cosmic Acceleration

Abstract:Cosmic acceleration is one of the most surprising cosmological discoveriesof the past century. Even the "simplest" explanations require new,cosmologically dominant energy components with exotic physical properties.Current and near-future experiments are seeking clues to the origin ofcosmic acceleration by measuring the history of expansion and structuregrowth with sub-percent precision over a wide span of redshift. I willreview the observational methods that underpin these measurementsand assess the current state of play, with particular attention to recentmeasurements from the Dark Energy Spectroscopic Instrument (DESI) whichsuggest that the properties of dark energy are evolving at a startling rate.I will discuss the prospects and challenges for the new generation ofexperiments --- DESI, the Euclid mission, the Vera Rubin Observatory,and the Nancy Grace Roman Space Telescope --- which aim to sharpen cosmologicalmeasurements by a factor of ten.