According to Relationships with Inhabitants of Celestial Bodies, dated 1947-06, J. Robert Oppenheimer and Albert Einstein considered relations with extraterrestrial beings both legally familiar in principle and difficult in practice.12 The document distinguishes between accepting the possibility of mutual understanding and determining the principles on which such relationships would rest.3 It presents communication through a language, together with a psychology sufficiently similar to that of humans, as a necessary first condition.4 Its proposed legal framework is a new field called Law Among Planetary Peoples, which would require changes so fundamental that it might no longer be regarded as international law.5
The document considers political recognition, settlement and conflict. It states that culturally and politically organised extraterrestrial beings would have a right to recognition as independent and sovereign peoples, while allowing only a necessary degree of legitimate defence if they became an imminent threat to Earth.67 It also discusses whether a human population could become culturally independent on another celestial body, with living conditions on the moon or Mars needing to support stable and partly economically independent life.8 In considering beings who might settle on Earth, it uses the term extraterrestrial biological entity (EBE).9 Possible roles for the United Nations (UN) include tacit approval of tutelage, although the document also argues that the UN would not automatically have authority over humanity.1011
A further subject is the legal status of celestial territory. The document defines res nullius as something belonging to nobody and proposes that an inhabited body would instead be res communis, with equal rights for celestial states.1213 It also addresses unidentified spacecraft, stating that their presence in Earth’s atmosphere was accepted de facto by the US military and linking unidentified space vehicles with security anxiety among major powers.1415 The possibility of mistaking such a craft for a missile is presented as a route to accidental nuclear war, and the situation is described as extremely perilous.1617 The document identifies both men as being based in USA, New Jersey, Princeton; an unnamed annotator additionally recorded an approach to George Marshall and a conversation with Gordon concerning its prospects for presidential consideration.18192021