The story of water is long. In fact, it starts at the big bang. Each step of the formation of water has relied on that beginning as well as the many steps afterwards including the formation of suns, planets, asteroids and rocks. This transfer and mixing of ingredients over space and time have led to the formation of our blue planet, with vast oceans, flowing rivers, and organisms that depend upon the existence of water for their survival. So what is the story of water? Let’s get into it!
Part 1 - The Sun
Water is formed from two hydrogen atoms and one oxygen atom. Hydrogen is the smallest atom and has been around since the beginning of the universe. This element is the fuel for the formation of stars, which become superheated forges where fusion occurs. During this process, the hydrogens combine to make helium, and then lithium, and all the way up to iron. This means that oxygen is created within the stars. After billions of years stars die and release all the elements within them in a spectacular supernova explosion. This spews out the ingredients for more stars, planets, and water to form.
Part 2 - The Formation of the Earth
When our solar system was formed, most of the hydrogen was blasted past the location of the earth further off towards where Jupiter is. So these atoms had to be returned to the earth through specific meteorites called Chondrites. These meteorites are about 20% water by weight, but that water is part of the structure of the rock, it isn’t a rock that is filled with liquid water. The only way that this water could be unlocked in liquid form was to melt it. While the earth was forming during the Hadean period (4.5-4 billion years ago), it was a ball of hot magma with lava oceans. Although there was some water on the earth at this time, most of the water was being brought down from the chondrites. But since it was so hot, the water evaporated and turned into water vapor. Eventually the atmospheric pressure became over 200x higher than the atmospheric pressure today. Just like a pressure cooker, when you increase the atmospheric pressure, you increase the temperature at which water needs to boil. So that paired with the cooling of the earth over time led to the accumulation of liquid water.
Part 3 - The Bombardment
That is how the oceans began, but surprisingly, our oceans today are made of two different types of water. As it turns out, there are different types of hydrogen. Light hydrogen is the one with one proton and one electron, which is what our oceans and water are mostly made of today. But the chondrite water that arrived early on and that can still be found in the rocks today is made of a heavier form of hydrogen, called Deuterium, with one electron, one proton, and one neutron. This is a common isotope of hydrogen that was formed during the big bang. This means that a lot of the water we see on earth today did not come from the early chondrites during the Hadean period. Instead, when asteroids were hit with protons in solar winds, those protons stole an electron from the deuterium, creating light hydrogen. Then this light hydrogen bonded to the oxygen in the asteroids and when it arrived on earth it melted into our magma oceans. Once the Earth’s crust cooled, this water was trapped in the mantle, and then was released through volcanic eruptions.
The story of water is epic and can be complicated. In fact, this is the major theory but the exact history is still a topic of debate today. The ingredients for water were forged in stars that were scattered out into the universe, where gravity caught them and pulled them back together in various forms along with the rest of the matter in our galaxy. Through the collection of oxygen on earth and the conversion and delivery of hydrogen from asteroids, the ingredients for water combined and filled up the oceans, rivers, lakes, and cups we have today.