Inertial wave lakes, and laboratory experiments. Rossby waves, geostrophic currents, and geostrophic winds are examples of inertial waves. Inertial waves are also likely to exist in the molten core of the rotating Earth. Inertial waves are restored to equilibrium by the Coriolis force, a result of rotation. To be precise, the Coriolis force arises (along with the centrifugal force) in a rotating frame to account for the fact that such a frame is always accelerating. Inertial waves, therefore, cannot exist without rotation. More complicated than tension on a string, the Coriolis force acts at a 90° angle to the direction of motion,
Winds in the Age of Sail them where they wanted to go. During the age of sail winds and currents determined trade routes and therefore influenced European imperialism and modern political geography. For an outline to the main wind systems see Global wind patterns. Pilotage or cabotage, in one sense, is the art of sailing along the coast using known landmarks. Navigation, in one sense, is the art of sailing long distances out of sight of land. Although the Polynesians were able to sail the Pacific (with great difficulty) and people regularly sailed north and south across the Mediterranean, before the time of Columbus nearly all