Postdoctoral Fellowships: Andrew Friedman: "Dark Energy, Fine-Tuning, and the Multiverse: Testing Theories in Modern Cosmology"

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

Recent developments in cosmology and theoretical physics have generated growing support for the idea that our universe may be just one of many in an ensemble of universes called the Multiverse. Evidence for the Multiverse includes the surprising 1998 discovery that the expansion rate of our universe is accelerating (and the inference that "dark energy" is causing the acceleration), and a combination of ideas from the theory of cosmological inflation and string theory. The usual arguments from fundamental physics suggest a colossal mismatch between the predicted and observed values of the dark energy, off by as much as 120 orders of magnitude. Faced with such discrepancies, several leading cosmologists have invoked the "Anthropic Principle": if many universes exist (each with different dark energy values) and only a certain range of such values would permit galaxies to form and life to evolve, then it need not be surprising that we find a particular value of dark energy within our own observable universe. However, the Anthropic Principle has long proven controversial both within and outside the scientific community. Intellectual Merit Our project aims to clarify how evidence is used to test cosmological theories that predict the existence of the Multiverse. Testing the predictions of recent cosmological theories has become a challenging and highly active topic at the cutting-edge of modern cosmology. Perhaps more than any discovery in recent scientific history, the mystery of dark energy has forced the scientific community to reconsider what constitutes a valid scientific theory. Such discoveries raise difficult questions at the boundary between astrophysics and the philosophy of science, which is precisely where this research project is located. Potential Broader Impacts The research will be integrated with education and public outreach, including a new interdisciplinary undergraduate course on "Philosophical Problems in Modern Astrophysics and Cosmology," articles and a book for scholarly and popular audiences, online podcasts, and the creation of a science museum exhibit.