World Ocean that covers and encircles most of Earth. If viewed from the southern pole of Earth, the Atlantic, Indian, and Pacific Oceans can be seen as lobes extending northward from the Southern Ocean. Farther north, the Atlantic opens into the Arctic Ocean, which is connected to the Pacific by the Bering Strait, forming a continuous expanse of water. Plate tectonics, post-glacial rebound, and sea level rise continually change the coastline and structure of the world ocean. World Ocean The World Ocean or Global Ocean (colloquially the sea or the ocean) is the interconnected system of Earth's oceanic waters, and comprises the
Origin of water on Earth ocean water removed most CO from the atmosphere but levels oscillated wildly as new surface and mantle cycles appeared. Study of zircons has found that liquid water must have existed as long ago as 4.404 ± 0.008 Ga, very soon after the formation of Earth. This requires the presence of an atmosphere. The cool early Earth theory covers a range from about 4.4 Ga to 4.0 Ga. In fact, recent studies of zircons (in the fall of 2008) found in Australian Hadean rock hold minerals that point to the existence of plate tectonics as early as 4 billion years ago.