Professor Emeritus of Astronomy
Local Interstellar Medium
For the last several years I have been devising a variety of novel ways to study the local interstellar medium (ISM) in an effort to understand its large-scale structure. Local here means out to a distance of at most a kiloparsec). The local ISM, especially in the northern hemisphere, has an axis in the L-60, 240 direction defined by an elongated "valley" of low density in the HI. Many of the components of the local ISM follow this same axis. The Sun is in this low-density valley which is flanked by regions of much higher density. The principal local centers of star formation are in these extended regions of higher density. The complexities of the local ISM in density and activity as shown by investigation of the velocity structures of the HI indicate the need for caution in inferring characteristics of the Galaxy at large from parameters derived locally or from small regions of the Galaxy.
Harold Weaver received his A.B. in Astronomy in 1940 and his Ph.D. in Astronomy in 1942, both from UC Berkeley.