The Aspen Center for Physics is a non-profit Center for research in Physics based in Aspen, Colorado, United States. The Center organizes workshops and conferences to facilitate interactions among research physicists. The Center was founded in 1962 by Purdue University postdoctoral fellow George Stranahan (later known for owning-operating the Flying Dog cattle ranch and co-founding the Flying Dog Brewery), University of Pennsylvania professor Michael Cohen and Aspen Institute director Robert W. Craig. While working on his doctoral dissertation at the Carnegie Institute of Technology in 1957, Stranahan first moved to Aspen, where he enjoyed the mountainous surroundings and fishing. In the aftermath of this experience, he was motivated to establish the center as a retreat for physicists.