Astronomer Dimitar Sasselov and his colleagues search for Earth-like planets that may, someday, help us answer centuries-old questions about the origin and existence of biological life elsewhere (and on Earth). Preliminary results show that they have found 706 "candidates" — some of which further research may prove to be planets with Earth-like geochemical characteristics.
http://www.ted.com/talks/dimitar_sasselov_how_we_found_hundreds_of_potential_earth_like_planets.html