Earth’s Water Supply: A Natural Process from the Beginning?
For years, scientists believed that Earth’s water supply came from a rain of hydrogen-soaked rocks and comets after the planet’s formation. However, a recent study challenges this theory, suggesting that water may have been a part of Earth’s composition from the start.
Researchers from the University of Oxford and the UK’s national synchrotron science facility conducted a study on rare meteorites known as enstatite chondrites (ECs), which are similar in composition to Earth’s original building blocks. Using X-Ray Absorption Near Edge Structure (XANES) spectroscopy, the team found high levels of hydrogen in these meteorites, indicating that Earth may have had enough hydrogen to form oceans without external sources.

The researchers suggest that hydrogen in the meteorites may have reacted with iron sulfide mineral pyrrhotite, preventing the hydrogen from being lost and eventually leading to water formation on Earth. This discovery challenges the idea that water arrived on Earth through external means.
According to James Bryson, an Earth scientist at the University of Oxford, the findings support the notion that water on Earth is a natural outcome of the planet’s composition, rather than a result of external events. The study provides crucial evidence that water on Earth is native to the planet.
Previous studies had hinted at the presence of hydrogen in ECs, but there was uncertainty about its origin. The latest research confirms that these meteorites contain intrinsic hydrogen, suggesting that Earth’s original rocks also had sufficient hydrogen for the planet to develop into its current state.
Thomas Barrett, another Earth scientist at the University of Oxford, highlights the significance of the discovery, emphasizing that the hydrogen sulfide found in the meteorites is unlikely to be from terrestrial contamination, further supporting the theory of Earth’s native water.
The research, published in Icarus, sheds light on Earth’s early formation and evolution, providing insights into the planet’s natural processes. The study challenges long-standing beliefs about the origin of Earth’s water supply, suggesting that water may have been part of the planet’s building blocks from the beginning.