Christopher Chyba, Professor of Astrophysical Sciences and International Affairs and Director of the Program on Science and Global Security, explains the ways that we are searching for extraterrestrial life and the difficulty of defining what “life” looks like in other parts of the solar system (“life as we do or don’t know it”). Presenting different planets and their characteristics, Professor Chyba discusses the ways in which scientists have searched for life in these environments and the resulting outcomes. Planetary discoveries and detection mechanisms are explored, along with debates about intelligent life. Presented as part of Alumni Day 2013