The Spitzer Space Telescope (formerly SIRTF) is a cryogenic infrared telescope launched into an orbit far from the Earth in 2003. Because the IR background radiation in space is a million times less than groundbased backgrounds, Spitzer is able to make observations that are 100 to more than 1000 times more sensitive than any previous experiment. UCLA has a strong involvement in Spitzer, since both Professor Jura and Professor Wright are interdisciplinary scientists on the Spitzer Science Working Group.