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

宇宙学和理论物理学的最新发展已经产生了越来越多的支持，认为我们的宇宙可能只是称为多元宇宙的宇宙系综中的许多宇宙之一。多元宇宙的证据包括1998年令人惊讶的发现，即我们宇宙的膨胀率正在加速（以及“暗能量”导致加速的推论），以及宇宙膨胀理论和弦理论的结合。基础物理学的通常论点表明，暗能量的预测值和观测值之间存在巨大的不匹配，相差多达120个数量级。面对这样的差异，几位主要的宇宙学家援引了“人择原理”：如果存在许多宇宙（每个宇宙都有不同的暗能量值），并且只有一定范围的暗能量值才允许星系形成和生命进化，那么我们在我们自己的可观测宇宙中发现特定的暗能量值就不必感到惊讶了。然而，人择原理长期以来在科学界内外都存在争议。智力价值我们的项目旨在阐明证据如何被用来检验预测多元宇宙存在的宇宙学理论。检验最近的宇宙学理论的预测已经成为现代宇宙学前沿的一个具有挑战性和高度活跃的话题。也许比近代科学史上的任何发现都更重要的是，暗能量的神秘迫使科学界重新考虑什么是有效的科学理论。这些发现在天体物理学和科学哲学之间的边界上提出了难题，而这正是本研究项目所处的位置。潜在的更广泛的影响本研究将与教育和公共宣传相结合，包括一门新的跨学科本科课程“现代天体物理学和宇宙学中的哲学问题”，面向学术和大众读者的文章和书籍，在线播客，以及建立一个科学博物馆展览。

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 MeritOur 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 ImpactsThe 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.