Pirates of the Caribbean: On Stranger Tides film provided him a long-awaited opportunity to work with Depp, and that his directing was helped by his experience as a choreographer—"the action sequences felt like big production numbers." On September 11, 2009, at Disney's D23 convention during a Disney event, Cook and Johnny Depp, in full Captain Jack Sparrow costume, announced that a fourth "Pirates" film was in development. The title was announced as "Pirates of the Caribbean: On Stranger Tides". Marshall visited the Pirates of the Caribbean ride in Disneyland for inspiration, eventually paying homage with a skeleton holding a magnifying glass in Ponce de León's ship. An
Discourse on the Tides ocean and gravitational forces, like that of the moon. Occurring invisibly, gravity was far too mystic for Galileo's consideration. Galileo did end the "Discourse on the Tides" with reservations that his theory may be incorrect and the hope that further scientific investigation will confirm his proposal. Still, his 1632 "Dialogue Concerning the Two Chief World Systems" omitted gravitational forces and included a reprisal of his tidal theory in its fourth section. Discourse on the Tides "Discourse on the Tides" () is an essay written by Galileo Galilei in 1616 as a letter to Alessandro Orsini that attempted to explain the