She discovered the first known multiple planet system in 1999 and contributed to the understanding of planet formation with analysis that quantified the impact of chemical composition on the formation of planets. From 2003 – 2008, she led an international consortium to carry out a search for planets around metal-rich stars; that project alone detected more than 50 new extrasolar planets. Some of these planets transit in front of their host stars and the measured decrement in starlight reveals the mass, size and density of the planets. Theoretical models of these transiting planets demonstrated an incredible diversity in the interior structure of unseen planets orbiting stars that are a hundred light years away. She is the PI for CHIRON, a high-resolution spectrometer commissioned at CTIO in March 2011, where her team is carrying out a search for rocky planets around our nearest stellar neighbors, the alpha Centauri A and B stars. In her lab at Yale, Fischer’s team is developing next generation instrument designs that aim to break current records and detect Earth analogues that will be targets in the search for life on other worlds.