More ‘Neon Colour’ can be found here.

The sex of the World Turtle is pivotal in proving or disproving a number of conflicting theories about the destination of Great A’Tuin’s journey through the cosmos. If, as the Discworld version of the popular “big bang theory” states, Great A’Tuin is moving to its mating grounds, then at the point of mating might the civilizations of the Disc be crushed or simply slide off? Attempts by telepaths to learn more about Great A’Tuin’s intents have not met with much success, mainly because they did not realise that its brain functions are on such a slow timescale. All they’ve been able to discern is that the Great A’Tuin is looking forward to something.

The other theory, described as being popular among the Discworld’s academics as the Discworld version of the steady state theory, which in-universe is known as the “steady gait” theory, is that he/she came from nowhere and is going to keep swimming through space to nowhere for ever. Eric shows Great A’Tuin being made instantly from nothing, seemingly in support of the theory that it came from nowhere and would continue at a constant pace into nowhere; however, the events in The Light Fantastic, in which the Great A’Tuin attended the hatching of eight baby turtles, each with four baby elephants and a tiny discworld of their own, would seem to support the Big Bang hypothesis.

Due to the Great A’Tuin’s travelling through the universe, the night sky of the Discworld, unlike that of our world, changes markedly over the course of decades, as the turtle departs older constellations and enters new ones. This means that astrologers must constantly update and alter their horoscopes to incorporate all-new zodiacs.