Pacific Ocean both the Water Hemisphere and the Western Hemisphere are in the Pacific Ocean. The equator subdivides it into the North Pacific Ocean and South Pacific Ocean, with two exceptions: the Galápagos and Gilbert Islands, while straddling the equator, are deemed wholly within the South Pacific. Its mean depth is . The Mariana Trench in the western North Pacific is the deepest point in the world, reaching a depth of . The western Pacific has many peripheral seas. Though the peoples of Asia and Oceania have traveled the Pacific Ocean since prehistoric times, the eastern Pacific was first sighted by Europeans
World Ocean Ocean, and Southern Ocean, defined by the International Hydrographic Organization (IHO) in 2000, based on evidence that this region of the World Ocean has a distinct ecosystem and a unique impact on global climate. In turn, oceanic waters are interspersed by many smaller seas, gulfs, and bays. A global ocean has existed in one form or another on Earth for eons, and the notion dates back to classical antiquity in the form of Oceanus. The contemporary concept of the "World Ocean" was coined in the early 20th century by the Russian oceanographer Yuly Shokalsky to refer to the continuous ocean