An ocean is a body of water that composes much of a planet's hydrosphere. As the world ocean is the principal component of Earth's hydrosphere, ocean is also called sea.The ocean covering approximately 71% of Earth's surface and 90% of the Earth's biosphere.The ocean contains 97% of Earth's water, and oceanographers have stated that less than 5% of the World Ocean has been explored. The total volume is approximately 1.35 billion cubic kilometers (320 million cu mi) with an average depth of nearly 3,700 meters (12,100 ft).
95% of the ocean is unexplored. What is down there? In 1960, Don Walsh and Jacques Piccard travelled around seven miles down, to the deepest part of the ocean, in search of this answers. Their voyage pushed the boundaries of human endeavour but gave them only a glimpse of life on the seafloor. It is so difficult getting to the bottom of the ocean that for the most part we have to resort to sending unmanned vehicles as scouts. The discoveries we’ve made so far from bizarre fish such as the barreleye, with its transparent head, to a potential treatment for Alzheimer’s made by crustaceans are a tiny fraction of the strange world hidden below the waves.⬲