Water is essential to life as we know it, yet the origins of this vital resource on Earth remain shrouded in mystery. For years, scientists have debated how water came to be on our planet, with one popular theory suggesting that it was delivered here by asteroids. These celestial bodies, which bombarded Earth during its formative years, are thought to have brought with them hydrogen, a key element in the formation of water molecules. However, groundbreaking research from the United Kingdom indicates that Earth may have possessed sufficient hydrogen of its own long before any asteroids arrived.

The study, conducted by a team of researchers at the University of Oxford, focuses on enstatite chondrite meteoritesspecifically, a specimen known as LAR 12252, which was collected from Alaska. Enstatite chondrites are intriguing because their composition closely mirrors that of Earth during its early history, roughly 4.55 billion years ago. This makes them valuable for understanding the building blocks of our planet. If these meteorites contain their own source of hydrogen, it implies that early Earth was similarly endowed, potentially negating the need for asteroids as the primary suppliers of water.

James Bryson, a planetary scientist at the University of Oxford and a co-author of the study published in the journal Icarus, emphasized the significance of this research. A fundamental question for planetary scientists is how Earth came to look like it does today, Bryson stated in a university announcement. We now think that the material that built our planetwhich we can study using these rare meteoriteswas far richer in hydrogen than we thought previously. This finding supports the idea that the formation of water on Earth was a natural process, rather than a fluke of hydrated asteroids bombarding our planet after it formed.

In their research, Bryson and his colleagues conducted an in-depth examination of the LAR 12252 meteorite, which had previously shown traces of hydrogen. However, concerns about potential contamination from Earth had cast doubt on those findings. The team speculated that the meteorite could contain significant amounts of native hydrogen bonded to sulfur. To investigate this further, they employed an intense beam of X-rays to search for sulfur compounds within the meteorite.

During their analysis of the matrix surrounding one of the tiny spherical components known as chondrules, the scientists made a crucial discovery: hydrogen sulfide. They found that the matrix contained vast amounts of the compound, amounting to five times the hydrogen found in the non-crystalline portions of the meteorites chondrules, which had previously yielded only limited hydrogen traces.

Importantly, areas of the meteorite that had clearly undergone terrestrial contamination, such as rust, showed little to no hydrogen. This suggests that the hydrogen sulfide identified in the matrix is likely intrinsic to the meteorite itself. Given that the composition of LAR 12252 closely resembles that of early Earth, the researchers concluded that our planet likely had enough hydrogen to produce the vast quantities of water we see today, even before it was impacted by asteroids.

We were incredibly excited when the analysis told us the sample contained hydrogen sulfidejust not where we expected, said Tom Barrett, the lead author of the study and a fellow scientist at Oxford. Because the likelihood of this hydrogen sulfide originating from terrestrial contamination is very low, this research provides vital evidence to support the theory that water on Earth is nativethat it is a natural outcome of what our planet is made of.

Understanding the origins of water is not just an academic exercise; it also touches on the profound question of how life itself emerged on our planet. Water is fundamental to all known living organisms, and this study offers new insights into the conditions that could have facilitated the inception of life as we know it.