THE EARTH’S water has been around for as long as the planet itself, according to a new scientific study.
For years researchers have been left baffled at the exact origins of our water, which covers more than two thirds of the planet.
Scientists previously thought that early in its early days the Earth’s surface was so hot that any water would have evaporated into space.
They believed that we should credit asteroids and comets that later struck the cooling world for the water we have today.
But a new study has found “compelling evidence” to suggest that H2O did not arrive by meteorite but in fact developed as the planet formed more than 4.5 billion years ago.
Researchers from the University of Glasgow and the University of Hawaii studied ancient rocks originating from near the Earth’s core found on Baffin Island, in the Canadian Arctic.
Their chemical analysis showed that water has been a fundamental part of the Earth since it was formed from the gradual accumulation of cosmic gas, dust and rocks.
An advanced probe was used to focus in on tiny pockets of glass inside the rocks and to detect the tiny amounts of water within.
The water they collected contained only tiny traces of an element – deuterium, a form of hydrogen – which is found in different types of planetary bodies in our solar system.
This suggests that the water was formed during the planet’s birth, and was not “carried” to the planet by comets or meteorites.
Dr Lydia Hallis, a Marie Curie research fellow at the Glasgow School of Geographical and Earth Sciences, spoke of the many years of research involved in the study.
She said: “The Baffin Island rocks were collected back in 1985 and scientists have had a lot of time to analyse them in the intervening years.
“As a result of their efforts, we know that they contain a component from Earth’s deep mantle.”
On their way to the surface, the rocks had never been affected by rock from outside bodies such as comets or meteorites.
She continued: “Research shows their source region has remained untouched since the Earth’s formation.
“Essentially they are some of the most primitive rocks we’ve ever found on the surface of the Earth, and so the water they contain gives us an invaluable insight into the Earth’s early history and where its water came from.
“We found that the water [in the rocks] had very little deuterium, which strongly suggests that it was not carried to the Earth after it had formed and cooled.
“It seems the Earth inherited its water directly from dust in the disk therefore earth’s water was accreted during the planet’s formation, rather than being added later by impacting water-rich material.
“Even though a good deal of water would have been lost at the surface through evaporation in the heat of the formation process, enough survived to form the world’s water.
“It’s an exciting discovery, and one which we simply didn’t have the technology to make just a few years ago.”
