Constant references apples and props were a joke on the fact Tasmania is Australia's largest producer/supplier of apples, so much so that the official state slogan printed on Tasmanian car license plates is "Tasmania: The Apple Isle".
Marie's farewell letter is based on a quote by Isaac Newton: "I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me."
Glenn Robbins, Peter Moon, Bryan Brown and Ross Higgins were considered for the role of Preston Preston.
Preston Preston was not based on an actual person.
The characters Preston Preston & Ernest Rutherford were based on founders of the Jehovah's Witness religion.