Abstract:     Only a few molecules were known to exist in outer space when OH, the first interstellar molecule to be discovered by radio techniques, was observed in 1963. By 2000, over 120 molecules had been discovered with the most complex, HC11N, having 13 atoms. The molecules are found in clouds of cold gas and dust which are distributed throughout the Milky Way Galaxy. These clouds are huge; they can have masses 100,000 times the mass of the sun and diameters of 300 light years. Molecular clouds fragment into small clumps which collapse to form stars which ionize their surroundings and begin to disrupt the remaining molecular clouds. The disruption can create new clumps which, in turn, collapse to form the next generation of stars. Because molecular clouds are opaque to "visible" light, infrared and radio telescopes are used to study the dramatic activity within them. Radio observations of molecular clouds made during the last decade will be described and recent results presented. Biography:     Dr. Hélène R. Dickel received her A.B. in mathematics from Mount Holyoke College in 1959 and her Ph.D. in astronomy from the University of Michigan in 1964. She is currently an Emerita Research Professor of Astronomy at the University of Illinois. She co-discovered the first formaldehyde maser in 1979 and is a pioneer in radio molecular spectroscopy using radio aperture synthesis techniques, including making some of the first images of molecular distributions with the Westerbork Synthesis Radio Telescope in the Netherlands, the Very Large Array of Radio Telescopes of the National Radio Astronomy Observatory, and the millimeter array of the Berkeley-Illinois-Maryland Association for which she was the BIMA Scheduler from 1994 through 1998. Prof. Dickel is the author of ~100 publications. Recent research includes radiative transfer modeling of star-forming regions. She and her astronomer husband, John, are "Faculty Friends" to the undergraduates living in the Snyder residence hall at the University of Illinois. For twenty years they hosted January term" student interns in astronomy from Mt. Holyoke, Wheaton, Oberlin, and Carroll Colleges. Interests outside of astronomy include ice dance (passed second USFSA silver dance test in 2001), cross-country skiing (when there is snow!), canoeing, hiking, and church choir.

Date:  Friday, September 21, 2001