Physics and Astronomy Colloquium Series
Spring 2012


Talks are scheduled for Thursdays at 12:40 PM in Room N304 of the Science and Engineering Building, unless otherwise indicated. Pizza and beverages are served at 12:20PM.

All are welcome!



29 March

Chemical Enrichment of Gas-Rich Galaxies in the Local Volume

Liese Van Zee
Indiana University

I will discuss the production of heavy elements via stellar nucleosynthesis and observational results tracing the enrichment of oxygen and nitrogen in nearby galaxies. I will examine the correlation between physical properties of galaxies and their chemical enrichment patterns in order to explore open and closed box chemical evolution models. Finally, I will present nitrogen-to-oxygen ratios observed in low mass galaxies and discuss the implications of these results on the star formation histories and chemical evolution of nearby galaxies.

5 April

Department Luncheon

12 April

The Physics and Chemistry of Mesoscopic Matter: Thermodynamics, Magnetism, and Metallurgy

Karl M. Unruh
Department of Physics and Astronomy
University of Delaware

The physical properties of matter evolve with increasing size from the discrete atomic properties of individual atoms and molecules to the familiar extensive and intensive properties of bulk systems. Between these two extremes lies a mesoscopic (from the Greek meso meaning intermediate) size regime in which matter can exhibit a rich variety of new, and sometimes unexpected, properties.

In this talk I will introduce a "definition" of mesoscopic matter, first in terms of a breakdown in the scaling relationships that characterize bulk matter and then in terms of a ratio of characteristic length scales. I will then briefly present three examples that demonstrate how the properties of mesoscopic matter differ -- or might be expected to differ -- from those of their bulk counterparts. In the first example I will focus on the melting and freezing behavior of small particles and describe a simple thermodynamic model that can account for the observed size dependence of both the transition temperature and the associated latent heat. I will then focus on the magnetism of exchange-coupled nanocomposites and the metallurgy of diffusional mixing at the nanoscale in order to demonstrate the potential for exploiting the properties of mesoscopic matter to obtain new, and potentially useful, materials.

19 April

no colloquium

26 April

no colloquium

3 May

10 May


Larry Marschall
Gettysburg College

On June 5, 2012, the planet Venus will be silhouetted against the face of the Sun for about 6 hours. This happened 8 years ago, on June 8, 2008, but before that no one alive had ever seen this rare event, since the last times it occurred were December 9, 1874 and December 6, 1882. Though few professional astronomers have scientific interest in the 2008 and 2012 transits, that was not the case in the past; in the 1700's and 1800's, the observation of these rare Transits of Venus was considered a matter of national importance. England sent Mason and Dixon to the island of Sumatra to observe one in 1761, even while the wars with France were raging. Captain Cook was sent around the world to observe the 1769 transit from a remote island in the South Pacific. And in the 19th Century, the superpowers, including the U.S., sent over 50 expeditions at a cost of billions of dollars, just to put observers under the shadow of Venus for a few hours. What was so important about the Transit of Venus? Dr. Marschall will answer this question and present pictures, movies, and stories that touch not just on astronomy, but also on Emily Dickinson, the U.S. Marine Band and, - of course - the Da Vinci Code, to both entertain and to explain the significance of this once-or-twice-in-several-lifetimes event. He'll also demonstrate a program developed by Project CLEA and the National Solar Observatory that uses modern images of the 2004 transit, taken with the GONG telescopes, to reproduce the measurements of the 19th Century astronomers - in the comfort of a laptop pc!

Come join us for what promises to be an entertaining, enlightening tour of the history, philosophy, and politics of 19th Century science! And please feel free to invite a friend to come along...

17 May

Evolutionary Optimization of Nervous Systems

Patrick Crotty
Colgate University

In the past fifteen years, huge advances in experimental technology and computational power have made it possible to model neurons and nervous systems to a far higher degree of biological accuracy than ever before. Large numbers of physicists, computer scientists, and mathematicians have been drawn into the new field of computational neuroscience, the long-term goal of which is a theory of cognition as mathematically rigorous as the laws of physics. Neuronal models involve many biophysical parameters that are believed to be genetically determined. However, the models are able to function over a much larger range of the parameters than we actually measure in nature. So why do the parameters that govern the behavior of neurons and nervous systems have the values that they do? This talk will discuss the mounting evidence that nervous systems ranging in complexity from invertebrate peripheral nerves to the human brain have been highly “tuned” by evolution to optimize their ability to quickly process information for the smallest possible metabolic energy cost. These results may help us to understand and quantify the basic organizational principles of the brain.

24 May

Using GPS to Study Earth's Ionosphere and Magnetosphere

Anthea Coster
MIT Haystack Observatory

Most of us know GPS as a means to track locations and times of events on Earth, and for such applications, ionospheric and magnetospheric effects are a nuisance to be eliminated. However, for space physicists, the situation is reversed: the very effects that disrupt ground-based applications of GPS present dramatic new ways to observe the space environment. In the last decade, total electron content (TEC) maps derived from the global set of GPS data have provided a paradigm shift in the ways that Earth's ionosphere and magnetosphere are observed. Prior to GPS, most scientific measurements of the magnetosphere-ionosphere were from individual observing sites or systems providing information about a region or a single point. With GPS, by combining individual measurements from multiple receivers, high resolution temporal and spatial information is available on a global scale. After a review of GPS fundamentals, including an explanation of how GPS is used to measure properties of the atmosphere and a brief history of ionospheric measurements with GPS, this talk will describe aspects of large-scale geomagnetic storms observed for the first time using TEC maps derived from GPS data. The new methods allow observations of conjugate features of the large-scale storms (in both the Northern and Southern Hemisphere), as well as correlation of these features with large-scale drainage plumes of plasma escaping from the high density inner part of Earth's magnetosphere during the storms. Combining GPS data with radar and magnetometer data from extensive networks of observatories provides a big picture view of geomagnetic storms and their impact on the upper atmospheric regions.

Thursday 24 May Evening

7:00 pm, Lippman 017

Lise Meitner and the Discovery of Fission

Anthea Coster
MIT Haystack Observatory

Lise Meitner was one of the pioneers of nuclear physics and co-discoverer, with Otto Hahn and Fritz Strassmann, of nuclear fission. Albert Einstein once called her the most significant woman scientist of the 20th century. Yet, by the 1970s, her name was nearly forgotten. With the publication of the book by Ruth Lewin Sime, "Lise Meitner: A Life in Physics," to some extent her name has resurfaced. I became familiar with Lise Meitner and her story when, in 1972, Dr. Sime corresponded with my father about details of Lise Meitner's escape from Germany. In 1938, my grandfather, Dirk Coster, was the person who got her out of Germany. Her escape from Germany reads like a spy novel, except that it was all true. This talk will be a combination of physics facts, excerpts from the film, "Path to Nuclear Fission: The Story of Lise Meitner and Otto Hahn," (a film by Rosemarie Reed), and personal stories heard from my father, aunts, and uncles. Lise Meitner's early years, her role in the discovery of nuclear fission, her escape from Germany, and the consequences that followed will be covered

31 May

Department Picnic

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Last Updated: 12 December 2011