One of the motivations for this work is the observation of high-energy cosmic rays that appear to violate the Greisen-Zatsepin-Kuzmin limit: the so-called GZK paradox.
External references
... - Juan Manuel Fangio, (Argentina) 1955 - Maurice Trintigant[?], (France) 1956 - Stirling Moss, (United Kingdom) 1957 - Juan Manuel Fangio, (Argentina) 1958 - ...