Seminar: Fall 2009

Seminars are held on Tuesdays, 3:45-4:45pm in SB110, unless otherwise noted. Meet at 3:30 in SB157 for refreshments (refreshments are available even on Tuesdays with no seminar!). See Calvin's Visitor Resources for maps and directions to the Science Building.

Schedules from previous semesters: Fall 2008, Spring 2008, Fall 2007, Spring 2007, Fall 2006, Spring 2006, Fall 2005, Spring 2005, Fall 2004, Spring 2004, Fall 2003, Spring 2003, Fall 2002, Spring 2002, Fall 2001, Spring 2001, Fall 2000, Spring 2000, Fall 1999.

September 29: Smashing New Results: Collisions in the Asteroid Belt
Professor L. Molnar and student Melissa Haegert
The dynamical history of the asteroid belt illuminates key questions about the past, present, and future of the solar system. Asteroid dynamics are driven by three successive processes: 1) violent collisions between asteroids produce families of fragments; 2) absorption and re-emission of sunlight gently modifies the fragments' orbits over hundreds of millions of years; until 3) they reach a resonant location, where interactions with Jupiter or Mars can remove them from the belt in just a few million years. We will discuss the dynamics of four collisional families. Our new discoveries allow us to determine the ages of each; the ages range from 5.7 milliion years for the youthful Karin family to 1500 million years for the ancient Flora family.

October 30: Lie Algebra & the Large Hadron Collider
Dr. Alex Dragt, Professor Emeritus, Physics Department, University of Maryland
Lie algebras were first discovered by mathematicians and extensively studied for their intrinsic beauty. Subsequently physicists learned that Lie algebras are also fundamental to the existence, attributes, and interactions of elementary particles. Elementary particles, always present in nature and particularly abundant in rare forms at the creation of the Universe, are produced and studied in the laboratory with the aid of high-energy accelerators such as the soon to be operational Large Hadron Collider. This talk describes how Lie-algebraic methods are also useful for the design of accelerators.