Arctic Ocean

Arctic Ocean, the smallest ocean, centering on the North Pole and connecting with the Atlantic through the Greenland Sea and with the Pacific through the Bering Strait. It covers about 4 million sq mi (10.3 million sq km), has an average depth of 4,362 ft (1,330 m), and includes an abyss with a known depth of 17,880 ft (5,450 m) and a continental shelf extending up to 1,000 mi (1,600 km) from the coast. Most of the Arctic Ocean is frozen all year. It was probably discovered by Greek sailors around 400 B.C. and was sailed by Vikings in the 800s. Norwegian explorer Fridtjof Nansen conducted the first scientific study in 1893–96.