Thrice Upon A Time is a science fiction novel by James P. Hogan, first published in 1980. Unlike most other time travel stories, Thrice Upon A Time considers the ramifications of sending messages into the past and/or receiving messages from the future, rather than the sending of physical objects through time.
It is December 2009. Murdoch Ross and his friend Lee Francis Walker visit Murdoch's grandfather, Sir Charles Ross, in his castle in Storbannon, Scotland. Sir Charles is a Nobel Prize recipient for his work in particle physics, more specifically the isolation of free quarks.
Supposedly, when a nucleon decays into three quarks, the first two quarks appear immediately, while the third quark appears only a brief moment later, on the order of a millionth of a yoctosecond. An accepted theory was that the original decay produced two quarks and a third unknown particle, dubbed a quason, which subsequently transformed into a third quark. Charles, however, offered a different, radical explanation: all three quarks were created at once, but the first two were propagated back in time. Charles dubbed the energy which had allowed the propagation through time as tau waves. Although his