An ocean is a body of saline water that composes much of a planet’s hydrosphere (all the waters on the Earth’s surface).
Approximately 71% of the Earth‘s surface is covered by oceans.
About 97% of all our planet’s water is contained in our oceans.
The total volume is approximately 1.35 billion cubic kilometers (320 million cubic miles).
There is only one ocean on the planet, but it is divided into five sections or five oceans. The five sections of the ocean are the Atlantic, Pacific, Southern, Arctic and Indian oceans.
The Atlantic Ocean, including both the northern and southern sections, stretches from the eastern seaboard of the Americas, to the western seaboard of Europe and Africa.
The Pacific Ocean reaches from the western seaboard of the Americas, all the way to Asia and Australia.
The Indian Ocean reaches from the western coast of Africa, along the southern edge of India, Australia and Asia, all the way down to where it meets the Southern ocean.
The largest ocean on Earth is the Pacific Ocean, covering around 30% of the Earth’s surface.
The second largest ocean on Earth is the Atlantic Ocean, it covers over 20% of the Earth’s surface.
The third largest ocean on Earth is the Indian Ocean, it covers around 14% of the Earth’s surface.
The fourth largest ocean on Earth is the Southern Ocean, it covers around 4% of the Earth’s surface.
The smallest ocean on Earth is the Arctic Ocean, it covers around 3% of Earth’s surface.
The Challenger Deep in the Mariana Trench is the deepest known point in Earth’s oceans. In 2010 the United States Center for Coastal & Ocean Mapping measured the depth of the Challenger Deep at 10,994 meters (36,070 feet) below sea level with an estimated vertical accuracy of ± 40 meters.
The average ocean depth is 3,700 meters (12,100 feet).
Light may be detected as far as 1,000 meters (3,280 feet) down in the ocean, but there is rarely any significant light beyond 200 meters (656 feet).
At the ocean’s deepest point, the water pressure is the equivalent of having about 50 jumbo jets piled on top of you. Yet even here life thrives, according to scientists who have pulled a plug of dirt from the seafloor.
To date, we have only explored about 5% of the world’s oceans.
About 70% of the oxygen we breathe is produced by the oceans.
The ocean produces oxygen through the plants (phytoplankton, kelp [photo below], and algal plankton) that live in it. These plants produce oxygen as a byproduct of photosynthesis, a process which converts carbon dioxide and sunlight into sugars the organism can use for energy.
The average temperature of the ocean surface waters is about 17 degrees Celsius (62.6 degrees Fahrenheit).
The ocean is blue because of the way it absorbs sunlight. When sunlight hits the ocean, the water strongly absorbs long-wavelength colors at the red end of the light spectrum, as well as short-wavelength light, including violet and ultraviolet. The remaining light that we see is mostly made up of blue wavelengths.
The longest mountain range in the world is found under water. Stretching over 56,000 kilometers (34,800 miles), the Mid-Oceanic Ridge is a mountain chain that runs along the center of the ocean basins.
The Ring of Fire an area in the basin of the Pacific Ocean contains over 450 volcanoes and is home to approximately 75% of the world’s active volcanoes. Also about 90% of the world’s earthquakes and 81% of the world’s largest earthquakes occur along the Ring of Fire.
The Great Barrier Reef, measuring 2,300 kilometers (1,400 miles), is the largest living structure on Earth. It can be seen from the Moon.
During winter the Arctic Ocean is almost completely covered in sea ice.
Although tap water freezes at 0 degrees Celsius (32 degrees Fahrenheit), seawater does not freeze until about minus 2 degrees Celsius because 3% of it is salt.
If all the ice in glaciers and ice sheets melted, the sea level would rise by about 80 meters (262 feet), about the height of a 26-story building.
100% of the Earth’s ocean floor has been mapped to a maximum resolution of around 5 kilometers.
Less than 0.05 percent of the ocean floor has been mapped to a level of detail useful for detecting items such as airplane wreckage or the spires of undersea volcanic vents.
Ocean waters do hold gold – nearly 20 million tons of it. However, if you were hoping make your fortune mining the sea, consider this: Gold in the ocean is so dilute that its concentration is on the order of parts per trillion. Each liter of seawater contains, on average, about 13 billionths of a gram of gold.
There’s up to US$60 billion in sunken treasure sitting at the bottom of the world’s oceans.
There are more artifacts and remnants of history in the ocean than in all of the world’s museums, combined.
10,000 shipping containers are lost at sea each year and about 10% of those are holding household chemicals that could be toxic to marine life.
6 billion kilograms (14 billion pounds) of garbage are dumped into the ocean every year. Most of it is plastic.
In three decades, the world’s oceans will contain more discarded plastic than fish when measured by weight, researchers say.
29,000 rubber ducks were lost at sea in 1992, and are still being found, revolutionising our knowledge of ocean science.
According to the UK Marine Foresight Panel, if we could capture just 0.1% of the total of the ocean’s kinetic energy caused by tides, we could satisfy the current global energy demand five times over. Indeed, it’s scalable and limitless… as long as the tides keep flowing.
The origin of Earth’s oceans remains unknown; oceans are thought to have formed in the Hadean period and may have been the impetus for the emergence of life.
The word “ocean” comes from the figure in classical antiquity, Oceanus, the elder of the Titans in classical Greek mythology, believed by the ancient Greeks and Romans to be the divine personification of the sea, an enormous river encircling the world.