Just how old is the water on Earth?
In short, some of our water could actually be older than the sun. A recent study estimated that there are water molecules on Earth that are up to 4.6 billion years old, which means they predate the formation of the Milky Way.
According to The Huffington Post, a significant portion of the water we use every day – to bathe in, to drink and to swim in – most likely came from space. Not only did the water not originate on our planet, it also predates the formation of our planet
How did they date our water?
It seems odd to be able to actually put a date on when a molecule of water was formed. One would think that all water molecules are the same – two parts hydrogen and one part oxygen. In theory, yes, this is the case. However, the scientists working on this problem have looked a little closer at the elements that make up the molecules.
It all started with scientists trying to work out exactly how old the solar system is. They started with focusing on the hydrogen to deuterium levels found in interstellar ice. Deuterium is essentially a ‘heavy hydrogen’, an isotope that contains an extra neutron. This isotope can only be formed in extremely cold temperatures – like the vacuum of space.
The next step for the scientists was to create a computer model that could simulate the circumstances in play when the Milky Way was formed. The idea was to see if the sun could provide the energy required to create deuterium to the levels that are found in interstellar ice, and in some water here on Earth.
The results showed that the sun simply could not produce enough of the isotope to satisfactorily explain the levels seen today. The conclusion that the scientists came to was that the large majority of water containing this ‘heavy hydrogen’ had to come from space, and from before our solar system came into being.
What does this mean for us?
The ‘heavy hydrogen’ found in a large portion of the Earth’s water doesn’t really mean anything for human beings. It’s always been there and always will. However, these findings could have a big impact on other scientific endeavours.
According to the scientists working on the study, as well as several others who have commented on the findings, this has far reaching implications for our search for life out in the universe. A planet’s water resources are essential for life to evolve. Therefore, if water from space was used in the creation of Earth, it could’ve been used in the creation of other planets in the Milky Way and beyond. This means that odds of there being more life out there have just got better.