Astrophysics Seminars

Though ~400 planets are currently known, discoveries at the observational frontiers continue to yield new classes of planets. The three gas giants directly-imaged orbiting HR 8799 comprise the first multi-planet system detected at wide separations...

Inflation is a (deceptively) simple idea in cosmology which ties directly to observational data on the one hand, and to difficult problems in formulating quantum gravity on the other hand. The mechanism behind inflation is sensitive to very high...

We have announced the results from 7 years of observations of the Wilkinson Microwave Anisotropy Probe (WMAP) on January 26. In this talk I will present the cosmological interpretation of the WMAP 7-year data, including the detection of primordial...

I will present a novel screening mechanism that allows a scalar field to mediate a long range ~Mpc force of gravitational strength in the cosmos while satisfying local tests of gravity. The mechanism hinges on local symmetry restoration in the...

The idea that peaks in the initial density fluctuation field may be important at later times has been a sort of guiding principle in most models of hierarchical structure formation for about three decades. I will discuss whether the qualitative...

Data from cosmic ray experiments have suggested the need for new, primary sources of cosmic rays. I will review the status of the anomalies and some of the models to explain them, including those models with dark forces. We'll discuss the near-term...