He was simply unable to let things be foggy. Since they always are, this kept him pretty active. J. Robert Oppenheimer on Enrico Fermi
Tau (Wikipedia) Tau /ˈtɔː, ˈtaʊ/ (uppercase Τ, lowercase τ, or τ; Greek: ταυ [taf]) is the 19th letter of the Greek alphabet, representing the voiceless dental or alveolar plosive IPA: [t]. In the system of Greek numerals, it has a value of 300.