text: Christy joined Oppenheimer, Lauritsen  and  Robert Bacher, who joined the faculty at Caltech in 1949, in Project Vista, a detailed 1951 study on how Western Europe could be defended against the Soviet Union. Christy was distraught at the outcome of the 1954 Oppenheimer security hearing. When he encountered Teller, who had testified against Oppenheimer, at Los Alamos in 1954, Christy publicly refused to shake Teller's hand. "I viewed Oppenheimer as a god", he later recalled, "and I was sure that he was not a treasonable person." Asked about his relationship with Teller in 2006, Christy said:
  In 1956, Christy was one of a number of scientists from Caltech who publicly called for a ban on atmospheric nuclear testing. The 1963 Partial Nuclear Test Ban Treaty that Christy advocated put an end to one of his most unusual projects. He worked with Freeman Dyson on Project Orion, the design of a spacecraft propelled by atomic bombs.
  During a sabbatical year at Princeton University in 1960, Christy began an investigation of Cepheid variables and the smaller RR Lyrae variables, classes of luminous variable stars. At the time it was a mystery as to why they varied. He used the knowledge of the hydrodynamics of implosion gained at Los Alamos during the war to explain this phenomenon. This earned him the Royal Astronomical Society's Eddington Medal for contributions to theoretical astrophysics in 1967.