world's largest ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, bounded by Asia and Australia in the west, and the Americas in the east.

At 165.2 million square kilometres (64.1 million square miles) in area, this largest division of the World Ocean – and, in turn, the hydrosphere – covers about 46% of the Earth's water surface and about one-third of its total surface area, making it larger than all of the Earth's land area combined. 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.The Mariana Trench in the western North Pacific is the deepest point in the world, reaching a depth of 10,911 metres (35,797 ft).

The eastern Pacific Ocean was first sighted by Europeans early in the 16th century. Spanish explorer Vasco Núñez de Balboa crossed the Isthmus of Panama in 1513 and named it Mar del Sur (South Sea). The ocean's current name was given by Portuguese explorer Ferdinand Magellan during the Spanish expedition of world circumnavigation in 1521, who encountered favourable winds as he reached the ocean and called it Mar Pacifico in Portuguese, meaning "peaceful sea".

The Pacific Ocean was named by legendary navigator Ferdinand Magellan. A native of Portugal, Magellan renounced his loyalty to that nation after King Emanuel rejected Magellan’s petition for a post within the royal navy. Magellan then left for Spain, which agreed to support Magellan’s claim of a western route to the Spice Islands through a seaway near the southern tip of South America.
On September 20, 1519, Magellan and a crew of 270 men set sail from Spain on their around-the-world voyage in five small vessels including his flagship Trinidad, Concepcion, San Antonio, Victoria, and Santiago. It took the fleet, or at least the three remaining ships in the fleet, 38 days to navigate the strait around South America that was to bear Magellan’s name. During the last week of November, the fleet emerged into what Magellan described as a “beautiful, peaceful ocean.” Thus, it was named the Pacific Ocean (“pacific” meaning “peaceful.”)
Upon entering the Pacific Ocean, Magellan mistakenly thought the Spice Islands were only a short voyage away. Nearly four months later, in March 1521, he and his crew finally reached what is known today as the Philippines. A few weeks later, he was fatally wounded after becoming involved in a dispute between warring Philippine tribes. Only one ship, Victoria, and 18 of Magellan’s original crew members returned to Spain, thereby completing the first circumnavigation of the globe. Although Magellan’s route proved impractical for the spice trade, his voyage has been called the greatest single human achievement on the seas.

Total Area :
The Pacific Ocean is the largest of the world’s five oceans, followed by the Atlantic Ocean, Indian Ocean, Southern Ocean, and Arctic Ocean. It covers an area of about 155 million square kilometers (about 60 million square miles). It is larger than the total land area of the world and about 15 times the size of the United States.

Depth:
Its average depth is 4,637 meters (2.8 miles). It is home to the deepest known point in the ocean — the Mariana Trench off Guam — which plunges to a depth of about 10,924 meters (nearly 7 miles). Because of the depth of the Pacific Ocean, tsunamis (huge waves created by earthquakes) can reach speeds of 750 kilometers an hour, the same velocity as a jet airplane.