Chuck Steidel, Caltech

Imaging the "Baryon Cycle" of Forming Galaxies

The rapid increase in the universal star formation density between z~6 and z~2 (12.5-10.5 Gyr ago) was driven by high rates of accretion onto galaxy-scale dark matter halos, but was simultaneously modulated by energetic feedback from massive stars, supernovae, and AGN activity whose large-scale effects remain uncertain. The competition between rapid accretion from the intergalactic medium and outflows driven by sources of energy and momentum originating near a galaxy's center is arguably the least well-understood aspect of the current galaxy formation paradigm.

No Physics Colloquium this week due to the Thanksgiving holiday.

Peter M. Hoffmann Wayne State University

The Physics of Life: Molecular Machines

Living beings are based on nanoscale machinery. This is no accident: the nanoscale is the only length scale at which autonomous, self-constructing machinery is possible. Only at this scale do thermal, electrical, chemical and mechanical energy scales converge. Moreover, this scale is dominated by thermal chaos. These unique circumstances give nanoscale systems the ability to easily transform different types of energy into each other and to self-assemble into ordered structures. Although living cells have taken advantage of the physics of the nanoscale for billions of years, technology is just beginning to exploit the very different rules governing this scale.