January 15, 2003
Wednesday - 4:00 pm in Swain West 119
Speaker: Sean Carroll, Enrico Fermi Institute
Title: Dark Energy and the Preposterous Universe

Abstract:
A variety of observations have led cosmologists to conclude that the universe is dominated by a mysterious form of "dark energy" (in addition to the well-established "dark matter", which now seems prosaic by comparison). This dark energy could be vacuum energy (a cosmological constant), or something dynamical and slowly evolving. All of the possibilities are very exciting, and future observations have promise for distinguishing between them. I will give an overview of the theoretical proposals for dark energy and the observational constraints which any model must satisfy.

the system by the addition of new loops and stirring of footpoints. When two loops collide they may reconnect, possibly triggering a cascade of further reconnection. The model reproduces the scaling behavior for flare statistics as well as some geometrical features of the coronal magnetic field. We predict that the distribution of net, signed magnetic flux in grid cells imposed on the photosphere is also power law.