Characterizing Extrasolar Earths

For thousands of years people have wondered, are we alone? Is there life elsewhere in the Universe? For the first time in human history we are on the way to being able to answer this question by plans to search for Earth‐like extrasolar planets. This review summarizes the current state of the scientific motivation for Earth‐like planet detection and characterization. The relevance of the June 2004 transit of Venus to the the characterization of extrasolar planets is also discussed.