Dealing with Dark Energy

Discoveries in the last few years have revolutionized our knowledge of the universe and our ideas of its ultimate fate. Measurements of the expansion of the universe show that it is not slowing down under normal gravity but accelerating due to an unknown, gravitationally repulsive “dark energy”. This may be a clue to new properties of quantum physics or of gravity beyond Einstein. I present an overview of the puzzles of dark energy and the means for unraveling them through cosmological probes, on both a generally accessible and a technical level. I also highlight the strong benefits of meshing supernova distance and weak lensing methods. Next generation experiments such as the Supernova/Acceleration Probe (SNAP) satellite would measure the supernova distance-redshift relation to high accuracy and map the evolution of structure and dark matter through gravitational lensing. These observations will explore the frontiers of physics and aim to uncover what makes up the still unknown 95% of our universe.