The "Oppenheimer hearing" refers to a high-profile security clearance hearing that took place in 1954. The hearing was conducted by the Atomic Energy Commission (AEC) and was centered around J. Robert Oppenheimer, the renowned physicist who had played a key role in the development of the atomic bomb during the Manhattan Project. The purpose of the hearing was to determine whether Oppenheimer's security clearance should be revoked due to concerns about his political associations and his perceived trustworthiness with classified information.