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Explained: How oceans were formed?

Arfa Javaid

Our planet Earth appears blue from space. The reason? Presence of water in abundant amount on the surface of Earth. Two-thirds of the Earth's surface is covered by the oceans (approximately 71%). The Earth comprises five oceans, namely, the Arctic Ocean, Atlantic Ocean, Indian Ocean, Pacific Ocean, and the Southern Ocean. But do you know how oceans were formed? If no, this article precisely describes that. 

The oceans started forming billions of years ago due to the continual 'degassing' of the Earth's interior. The water was present in the form of gas until the Earth cooled down below 212 degrees Fahrenheit. Let us have a look at the two possible ways that led to the formation of oceans on the surface of Earth.  

Water Vapour and Condensation

Around 4.5 billion years ago, no liquid water was present anywhere on Earth. The Earth was so hot that the rocks were molten (they were liquid). When volcanic eruptions took place, one of the gases came out as steam (water vapour). As the Earth cooled off, the water vapour condensed and rained back down onto the surface of the Earth for millions of years. Some scientists think that is how some of the water came on the surface of Earth.

Comets, Asteroids and Meteorites

Comets are huge chunks of ice and dust that were left after the formation of stars and other planets. Asteroids are large rocks that are known as planetoids or minor planets. These were left behind when the planets and stars formed. 

When an asteroid enters the Earth's atmosphere, it is called a meteor. Usually, meteors burn up while passing through the Earth's atmosphere, but sometimes some pieces survive. These pieces are called meteorites. Some scientists think that the rest of the water in the oceans came from comets, asteroids and meteors.

Carbonaceous Chondrite, a kind of meteorite, has lots of water in it. Recently, scientists have found that the water in carbonaceous chondrites matches the water found on Earth!

As the water drained into the great hollows on the surface of the Earth, the oceans came into existence and due to the gravitational force, the water could not leave the planet.

What is an Ocean?

It is a large area of water between continents that covers approximately 71% of the Earth's surface. 

List of Ocean Currents of the World


Which is the saltiest ocean in the world?

The Atlantic Ocean is the saltiest ocean in the world.

What are the 5 oceans in the world?

The five oceans in the world are as follows: Arctic Ocean, Atlantic Ocean, Indian Ocean, Pacific Ocean, and the Southern Ocean.

Which is the largest ocean in the world?

The Pacific Ocean is the largest Ocean in the world.

Which is the smallest ocean in the world?

The Arctic Ocean is the smallest ocean in the world.

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