This course introduces students to a new field, Astrobiology, where scientists trained in biology, chemistry, astrophysics and geology combine their skills to investigate life's origins and to seek extraterrestrial life. Topics include: the origin of life on earth,the prospects of life on Mars, Europa, Titan, Enceladues and extra-solar planets, as well as the cosmological setting for life and the prospects for SETI. 255 is the core course for the planets and life certificate.

How do we observe and model the universe? We discuss the wide range of observational tools available to the modern astronomer: from space-based gamma ray telescopes, to globe-spanning radio interferometry, to optical telescopes and particle detectors. We review basic statistics and introduce students to techniques used in analysis and interpretation of modern data sets containing millions of galaxies, quasars and stars, as well as the numerical methods used by theoretical astrophysicists to model these data. The course is problem-set-based and aims to provide students with tools needed for independent research in astrophysics.