Astrophysics Seminars

In a planetary system with well-spaced planets, there is a nonlinear instability that can lead to chaotic behaviour. One of the planets may gradually become unstable, in which case its orbit can become highly eccentric and/or inclined. If an...

Theories that attempt to explain the observed cosmic acceleration generally introduce new degrees of freedom (such as a scalar) that are active on large scales but must be screened on small scales. We show that O(1) equivalence principle violations...

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...