There are four oceans. In order of their size, they are : Pacific Ocean, Atlantic Ocean, Indian Ocean and Arctic Ocean.
» The explorer Ferdinand Magellan, who circumnavigated the Earth, named the ocean 'Pacific' meaning calm or peaceful.
» The Pacific Ocean (Area: 166,240,000 sq. km) is the largest ocean of the world. It is the deepest ocean with an average depth of 4,200 m.
» The Mariana Trench is the world's deepest trench with a depth of 11,033 metres (36,201 feet).
» Most of the islands of this ocean are of volcanic or coral origin.
» The Atlantic Ocean (Area : 8,65,60,000 sq. km) is the second largest ocean in the world.
» Its name is derived from Atlas, a Titan (giant) in Greek mythology. The Atlantic Ocean has the longest coastline.
» The Atlantic Ocean is the busiest ocean for trade and commerce since its shipping routes connect the two most industrialized regions, namely Western Europe and N.E. United States of America.
» The Atlantic Ocean was formed millions of years ago when a rift opened up in the Gondwanaland and the continents of South America and Africa separated. The separation continues even today and the Atlantic Ocean is still widening.
» The continental islands of Newfoundland and British Isles are the major ones.
» Volcanic islands are fewer and they include those of Cuba, Jamaica and Puerto Rico. Iceland is the largest island of volcanic origin.
» The Indian Ocean (Area : 73,430,000 sq. km) is the only ocean named after a country.
» The Indian Ocean is deeper than the Atlantic Ocean.
» It contains numerous continental islands, Madagascar and Sri Lanka are being the largest ones.
» Some of the islands of volcanic origin are those of Mauritius, Andaman and Nicobar, Seychelles, Maldives and Lakshadweep are of coral origin.
» The Arctic Ocean (Area : 1,32,30,000 sq. km) is the smallest of all the oceans.
» It lies within the Arctic Circle, hence the name Arctic Ocean.
» The North Pole lies in the middle of the Arctic Ocean.
» Most of the parts of Arctic Oceanremains frozen with thick ice for most of the days every year.
» It is the shallowest of all oceans, with an average depth of 1,500 m.
» It has the least salinity of all the oceans. It has a salinity of 20 unit per thousand.