ERIK ZACKRISSON: Why Here? Why Now? Anthropic Reasoning in the Search for Extraterrestrial Life

ABSTRACT:

In recent years, astronomers have established that nearly all stars host planets, and that some of these planets may have properties somewhat similar to Earth. This finding has revitalized the age-old question “Are we are alone in the Universe?”, and significant resources are now being devoted to making the first detection of life beyond Earth. Despite the widely held view in astronomy that only empirical searches can set meaningful constraints on the presence of life on cosmic scales, there is a controversial line of reasoning that suggests that strong conclusions about the spatial and temporal distribution of extra-terrestrial life can be drawn from our own position in space and time, when coupled to the assumption that we are typical observers of the Universe. If correct, this would imply that many of the current efforts in the search for life in outer space are misdirected. In this seminar, I will explain how such conclusions come about and explore some of the underlying assumptions.