Comets are chance visitors from the icy reaches of the outer Solar
System. In this lecture I describe the properties of comets, their
historical importance, and introduce the "dirty snowball" model of a
comet nucleus. At the end of class I created a model of a comet nucleus
from common household and office materials, unfortunately I could not
arrange for a videographer in time. Recorded 2007 Nov 28 in 1000
McPherson Lab on the Columbus campus of The Ohio State University.