Duane H. Pontius, Jr.

T. Morris Hackney Professor of Physics

Office: Stephens Science Center 124
Research Lab: SSC 116 
Phone: 205 226-4765 
Fax: 205 226-3078 
E-mail user name: dpontius
Domain: bsc.edu
Office Hours: click here
Jupiter movie
Birmingham-Southern College
Department of Physics
900 Arkadelphia Rd
Box 549022
Birmingham, AL 35354

Jupiter's animation provided 
courtesy of António Cidadão. 
Click the picture for more information.

Current and upcoming courses: Courses I've taught recently at BSC include General Astronomy, Physics of Music, General Physics I & II, Modern Physics, Mathematical Methods for Physics, Optical Physics, Thermal Physics, Classical Mechanics, Electricity and Magnetism, and my honors course, "Science, Physics, Music."

"We don't give A grades for large volumes of C work" - John Strohl, in memorium

I study the magnetospheres of Jupiter and Saturn and the dynamics of plasma trapped within them.  These planets are particularly interesting because both have moons imbedded within them that contiually spew huge amounts of material into outer space.  More detailed information can be found accompanying my publications on the topic.  Io is the innermost Galilean moon of Jupiter, and intense volcanic activity makes it spew off roughly a ton of mass every second. Once ionized, this material is swept up into a large cloud of gas that encircles the planet and rotates with it, forming a huge, million-ton doughnut of gas around Jupiter.  The torus is centered on Io's orbit, which is about the same size our own moon's orbit about the Earth.  However, the ionized gas (called a plasma) rotates once every ten hours, so centrifugal forces are overwhelmingly larger than gravity. (Just imagine the moon going around the Earth two and a half times a day rather than once a month!) It's a really fascinating object for study, and we are fortunate to be able to do so via telescopes from the Earth as well as spacecraft that visit Jupiter.  For more information, see my article on the torus, The Nebula in Our Own Backyard, which appears in the Nov/Dec 2000 issue of Mercury, published by the Astronomical Society of the Pacific.  

One of Saturn's moon's was recently to exhibit similar behavior, though the discovery was quite unexpected.  Enceladus' diameter is one-seventh that of Io, though their orbital radii are similar, so the gravitational tidal forces that stress and flex Io and heat it internally are several orders of magnitude weaker at Enceladus.  Nevertheless, on 14 July 2005, the Cassini spacecraft passed within 150 km of Enceladus and found dramatic evidence that a huge cloud of material is continually ejected from the surface.  These atoms and ions are dissociation products of water molecules, hinting that there must be liquid water near Enceladus' surface.  The mechanism for maintaining such warm pockets in an environment that would otherwise be hundreds of degress below freezing is still under debate.  However, the data provide unambigous evidence and the photographs are breathtaking.

My role in all this was in developing a theoretical model to relate the spatial distribution of mass loading to the deflection of plasma away from Enceladus.  Those measurements were made by the Cassini Plasma Spectrometer (CAPS), and the analysis is described in a pair of papers, one in Science, the other in the Journal of Geophysical Research.  (Click for a preprint of Enceladus: A significant plasma source for Saturn’s magnetosphere, by me and Tom Hill.)  Further details of my professional history are in my curriculum vitae, or you can go directly to my publication list.  Some pre- and reprints are available. Then there are the personal photos and odd stuff

Sites with information of occasional utility

Stuff for when work becomes overwhelming: