Observational Probes of Dark Energy

Abstract: The cause for the observed acceleration in the expansion of the universe is unknown, and referred to as "dark energy" for convenience. Dark energy could be an unknown energy component, or a modification of Einstein's general relativity. This dictates the measurements that are optimal in unveiling the nature of dark energy: the cosmic expansion history, and the growth history of cosmic large scale structure. I will examine Type Ia supernovae and galaxy clustering as dark energy probes, and discuss recent results and future prospects.