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Sears Applied Technologies Center
Guilford Technical Community College
Jamestown, NC

March 1st


Public Lecture - Friday, 28 February, 7:00 p.m.

Spinning Pliers, the Chaotic Obliquity of Mars, and the Existence of Extraterrestrial Life

Gordon Emslie, Western Kentucky University, AAS Harlow Shapley Visiting Lecturer

Dr. Gordon Emslie is Provost and Vice President for Academic Affairs  and Professor of Physics and Astronomy at Western Kentucky University  He was born in Hamilton, Scotland, and attended the University of Glasgow, earning baccalaureate and doctoral degrees in Astrophysics.  He was a Research Assistant at the Harvard-Smithsonian Center for Astrophysics and a Research Associate at the Institute for Plasma Research at Stanford University.  He then served as a faculty member at the University of Alabama in Huntsville, where he became Chair of the Department of Physics and Dean of the School of Graduate Studies.  Before coming to Western Kentucky he held the position of Associate Vice President for Research and Dean of the Graduate College at Oklahoma State University.

Dr. Emslie's research interests are in high-energy solar astrophysics, and he is a co-investigator on the NASA Ramaty High Energy Solar Spectroscopic Imager (RHESSI) mission. He is also a licensed Professional Engineer and an officer in the AAS Solar Physics Division.  In his spare time, he jumps out of perfectly good airplanes and flies 1940-vintage DC-3s.

Dr. Emslie comes to GTCC through the Harlow Shapley Visiting Lectureship Program of the American Astronomical Society.  Astronomer Harlow Shapley (1885-1972) served for more than 30 years as director of Harvard College Observatory. He is most notably remembered for his work in identifying the center of the Milky Way and determining our solar system's location in the galactic outskirts. He strived to bring astronomy to the public through authoring several popular books and was a cofounder of the United Nations Educational, Scientific and Cultural Organization (UNESCO). In his honor, the Harlow Shapley Visiting Lectureship was created at the American Astronomical Society (AAS) with funding from the National Science Foundation and the Harlow Shapley Visiting Lectureship Endowment Fund. The AAS Harlow Shapley Visiting Lectureship Program provides two-day visits by professional astronomers who bring the excitement of modern astronomy and astrophysics to North American colleges of all types, especially those not offering an astronomical degree.

 


About the Talk: The basic principles of rigid body rotation have been known for over two hundred years; yet the resulting motion is sometimes quite surprising. A movie from a Space Shuttle mission shows this quite vividly: while the rotation of an astronaut is straightforward (like a spinning ice skater), the motion of a set of pliers is quite fascinating and totally unexpected.  I will discuss how these surprising motions come about.

The rotation of planets offers equally surprising behaviors. As a striking example, the tilt angle of Mars undergoes dramatic transitions, so that the seasonal variation of temperature on the Martian surface is quite different now than in the distant past.  Why has the Earth not suffered such dramatic changes in tilt?  The surprising answer to this question means that we may have to drastically reduce our estimates for the number of habitable planets in the Galaxy.  This perhaps explains why a recently-completed five year search, in ten million radio channels, produced not a single example of a signal from our galaxy that is attributable to extraterrestrial life.

 

TriStar - Saturday, 1 March

Time Activity
8:30 Doors Open - Coffee and Refreshments
9:20 Welcome and Announcements
9:30 Don Smith, Guilford College
What Can Globular Clusters Tell Us about the Universe?

The Pisgah Astronomical Research Institute's Astronomical Photographic Data Archive (PARI's APDA) contains over two hundred thousand glass plate photographs of the sky.  In particular, there are several thousand plates from the University of Michigan's CTIO survey.  Instead of focusing the stellar light to points, these plates had a prism in the optical path that smears the stars' light into rainbow-like spectra.  From these spectra, the type of star can be identified through the presence (or absence) of atomic energy lines.  In total, these plates contain hundreds of thousands of stars that have not been classified - a daunting prospect for any individual.  PARI has established a crowd-sourcing web site (scope.pari.edu) that offers anyone the opportunity to try their hand at classifying a small sample of these stars.  However, in principle, an artificial neural network could be trained to carry out the classification en masse.   I will describe my ongoing project to process these glass plates: to extract stellar spectra from scanned, digitized versions of the images and to train an artificial neural network to classify the extracted spectra.  The results of this project could be interesting from an astronomical point of view, extending our knowledge of the demographics of nearby stellar populations, as well as from an artificial intelligence standpoint, providing a way to compare the results of artificial and biological neural networks' efforts to solve the same task.

10:30 Break
11:00 Gordon Emslie, Western Kentucky University, AAS Harlow Shapley Visiting Lecturer
Acceleration of High-energy Particles in Solar Flares
Solar flares produce copious amounts of X-rays that in turn require the acceleration of even more copious amounts of energetic electrons.  The number and energetic content of these electrons present some serious issues, in view of some rather basic principles that we learn in freshman physics, but which have only recently come to light in the solar flare context. In particular, application of Ampère's circuital law and Faraday's law of induction to solar flares forces us into some rather challenging problems involving source geometry and electric current closure. Alternative models of "stochastic" particle acceleration, which address these issues rather nicely (and which I colloquially refer to as "Batman acceleration" and "Freeway acceleration") will be reviewed.
12:00 Lunch Break
2:00 Kristen Thompson, Davidson College
The Role of Magnetic Fields in the Star Formation Process
The details of the star formation process are not well understood, despite many theoretical and observational studies.  It has long been known that stars form in the gravitational collapse of an interstellar molecular cloud.  However, the formation process has been found to be very inefficient, with the observed star formation rate nearly 100 times less than expected if clouds collapse and form stars on the free-fall time scale.  This suggests that internal mechanisms of cloud support likely play an important role in the evolution of a molecular cloud.  Two prevailing theories of star formation have thus emerged, one placing emphasis on the support provided by magnetic fields, and the other on turbulence.  To distinguish between these two models of star formation, I have executed the first observational survey designed to determine the role of magnetic fields in the inter-core regions of molecular clouds.  I will present the findings of this study and discuss what they may tell us about the role of magnetic fields in star formation.
3:00 Break
3:30 Grant Thompson, Georgia Regents University
Active Galactic Nuclei and the Nature of Their Tori

In the framework of active galactic nuclei (AGN), a galaxy's supermassive black hole is surrounded by a dusty torus whose clumpy configuration allows for either direct or obscured views toward the central accretion.  These viewing angles give rise to a variety of AGN classifications; however, the angles are not directly observable.  Synthetic models do provide a means to determine them in addition to other parameters that describe the nature and characteristics of the torus in general.  Employing the models with MIR spectroscopic observations of a large sample of AGN allows us to acquire a further understanding of the clumpy torus structure.

4:30 Prize Drawings
4:50 Final Announcements & Adjourn
7:00 Observing session at Cline Observatory (weather permitting)

Last update 02/26/2014