Body of salt water stretching between Africa in the west, Australia in the east, Asia in the north, and Antarctica in the south. With an area of 28,360,000 sq mi (73,440,000 sq km), it covers approximately one-seventh of the Earth's surface, and it is the smallest of the world's three major oceans (seeAtlantic Ocean; Pacific Ocean). Its greatest depth (24,442 ft [7,450 m]) is in the Java Trench. Its chief marginal seas include the Red Sea, Arabian Sea, Persian Gulf, Andaman Sea, Bay of Bengal, and the Great Australian Bight. Its major islands and island groups include Madagascar, Sri Lanka, and the Mascarenes.