The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about 41,100,000 square miles, it covers approximately 20% of the Earth's surface and about 26% of its water surface area. The first part of its name refers to the Atlas of Greek mythology, making the Atlantic the "Sea of Atlas."
The oldest known mention of this name is contained in The Histories of Herodotus around 450 BC. Another name historically used was the ancient term Ethiopic Ocean, derived from Ethiopia, whose name was sometimes used as a synonym for all of Africa and thus for the ocean. Before Europeans discovered other oceans, the term "ocean" itself was to them synonymous with the waters beyond Western Europe that we now know as the Atlantic and which the Greeks had believed to be a gigantic river encircling the world.
The Atlantic Ocean appears to be the second youngest of the five oceans. Apparently it did not exist prior to 130 million years ago, when the continents that formed from the breakup of the ancestral super continent, Pangaea, were drifting apart from seafloor spreading. The Atlantic has been extensively explored since the earliest settlements along its shores.
The Vikings, the Portuguese, and Christopher Columbus were the most famous among early explorers. After Columbus, European exploration rapidly accelerated, and many new trade routes were established.
As a result, the Atlantic became and remains the major artery between Europe and the Americas (known as transatlantic trade). Scientific explorations include the Challenger expedition, the German Meteor expedition, Columbia University's Lamont-Doherty Earth Observatory and the United States Navy Hydrographic Office.
The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between the Americas to the west, and Eurasia and Africa to the east. As one component of the interconnected global ocean, it is connected in the north to the Arctic Ocean (which is sometimes considered a sea of the Atlantic), to the Pacific Ocean in the southwest, the Indian Ocean in the southeast, and the Southern Ocean in the south. (Other definitions describe the Atlantic as extending southward to Antarctica.) The equator subdivides it into the North Atlantic Ocean and South Atlantic Ocean.
The Atlantic Ocean is bounded on the west by North and South America. It connects to the Arctic Ocean through the Denmark Strait, Greenland Sea, Norwegian Sea and Barents Sea. To the east, the boundaries of the ocean proper are Europe, the Strait of Gibraltar (where it connects with the Mediterranean Sea, one of its marginal seas and, in turn, the Black Sea) and Africa.
In the southeast, the Atlantic merges into the Indian Ocean. The 20° East meridian, running south from Cape Agulhas to Antarctica defines its border. Some authorities show it extending south to Antarctica, while others show it bounded at the 60° parallel by the Southern Ocean.
In the southwest, the Drake Passage connects it to the Pacific Ocean. The man-made Panama Canal links the Atlantic and Pacific. Besides those mentioned, other large bodies of water adjacent to the Atlantic are the Caribbean Sea, the Gulf of Mexico, Hudson Bay, the Arctic Ocean, the Mediterranean Sea, the North Sea, the Baltic Sea, and the Celtic Sea.
Covering approximately 22% of Earth's surface, the Atlantic is second in size to the Pacific. With its adjacent seas it occupies an area of about 41,100,000 square miles; without them, it has an area of 31,800,000 square miles. The land that drains into the Atlantic covers four times that of either the Pacific or Indian oceans. The volume of the Atlantic with its adjacent seas is 85,100,000 cubic miles and without them 77,640,000 cubic miles.
The average depth of the Atlantic, with its adjacent seas, is 10,955 feet; without them it is 12,881 feet. The greatest depth, 28,232 ft, is in the Puerto Rico Trench. The Atlantic's width varies from 1,770 miles between Brazil and Sierra Leone to over 4,000 miles in the south.