Diffusion exponent, α (Eq. (14)), as a function of time for a sticky chaotic orbit (close and inside the blue orbit of Figs. 8, 9). (a) For approximately the first 1400 iterations (approximately 14 Hubble times) the slope has a mean value around zero, denoting a regular behaviour due to stickiness phenomena, and then gets diffused outwards through a superdiffusing procedure. (b) After escaping from the system it presents a superdiffusing (or superballistic) behaviour and seems to converge to a ballistic motion (with α → 2 as t → ∞).