The Social Value of Dark Energy

Abstract: Astrophysics is a social enterprise exemplified here by the Dark Energy Survey (DES) which completed its fieldwork in 2019 after 16 years of preparation and observation, while data analysis continues. Society funds astrophysics on a grand scale. For human capital and for governance the discipline draws on a self-governing "republic of science", while the funds were provided by philanthropists in the past, and by governments today. The benefits accrue initially to scientists themselves, in the form of a rewarding vocation. For the social benefit it is tempting to apply formal cost benefit analysis, but that approach ignores the option value of science and imposes questionable assumptions from welfare economics. Astrophysics generates some useful spinoffs, offers attractive careers, appeals to the popular imagination, speaks to metaphysical cravings and constitutes a good in itself. The rise of AI also suggests a role in exploring future habitats for intelligence and cognition.