David Wittman, Professor, University of California, Davis
David Wittman is a professor at the University of California, Davis. He has discovered millions of galaxies as co-PI of the Deep Lens Survey, which was awarded over 100 nights on 4-m telescopes to study a representative sample of the universe. But discovering millions of galaxies was just the easy part. He analyzed the galaxies' shapes to reveal subtle distortions caused by the gravitational fields of foreground masses, an effect called weak gravitational lensing. He was the first to detect cosmic shear, or weak lensing by the large-scale structure of the universe. He was also the first to detect a cluster of galaxies through its gravitational effects alone, and the first to combine source redshift information with lensing to probe structure in three dimensions (tomography).