Scientific Colloquium
November 21,  2003


Many of the dramatic advances in astronomy in the past few
decades have come from the opening of new windows of the
electromagnetic spectrum; most of these are made possible by the
availability of space platforms. Very High Energy Gamma Ray
astronomy (E > 100 GeV) using ground-based techniques has
recently made remarkable advances, particularly in the realm of
extragalactic studies. The detection of TeV cosmic cannons,
relativistic jets from active galactic nuclei, complements the
work of EGRET on the Compton Gamma Ray Observatory. New
observatories, such as VERITAS, will perform the same function
with GLAST.