There are numerous theories about how water became present on Earth and mostly the theories fall into two categories: Earth was born with it, and water was delivered here via extraterrestrial entities. But before all of that, let’s understand what water is! 

According to chemistry, a water molecule is made up of two atoms of oxygen and one molecule of oxygen. While it is believed that hydrogen was created during the Big Bang theory and that oxygen was formed in the cores of stars bigger than the sun. 

A ginormous amount of water exists in our galaxy in gaseous form. This brings us to the first theory of the origin of it. 

According to NASA, asteroids and comets inherited water and left the debris made from it after the solar system’s formation about 4.5 million years ago. Countless of these water-rich small bodies collided with the earth which later enriched the earth with water. 

Origin Stories  

Some other origin stories state that icy comets far from the solar system locked water into one form, while rocky materials closer to the sun reacted with hydrated minerals to lock it in another form. Another theory suggests that Earth was born with water.

A recent study stated that a type of meteorite, believed to represent the raw materials that formed earth, contained sufficient hydrogen to delivered to Earth. But then the question arises: How did the water come to the surface? 

Scientific theories 

Volcanic Activity theory 

Volcanic activity could have released the trapped water in Earth’s interior as water vapor, which condensed. 

Theia theory 

One study suggests that the supposed collision of a world named Theia with Earth over 4.4 billion years ago pilled its water onto our planet and helped in moon formation. 

Earth made its own water theory 

This is another theory by a group of researchers. The researchers used mathematical modeling to demonstrate the presence of water in Earth’s existence.

Some suggest that the interactions between the magma ocean and a molecular hydrogen proto atmosphere could have given rise to water and the earth’s overall oxidized state.