We review the applications of order and chaos in various branches of astronomy. Order and chaos appear in generic dynamical
systems, including the sun and other stars, the solar system and galaxies, up to the whole Universe. We discuss in particular
the various types of orbits in galaxies, emphasizing the role of diffusion of chaotic orbits and the escapes to infinity.
Then we consider chaos in ... [Show full abstract] dissipative systems, like gas in a galaxy, chaos in relativity and cosmology, and chaos in stellar
pulsations and in the solar activity.