A recent study suggests that Earth may have formed with the necessary components for water, challenging the prevailing theory that our planet received most of its water from external sources like comets and asteroids. The research, published in the journal Icarus on April 16, 2025, focuses on a rare type of meteorite known as enstatite chondrites.
Enstatite chondrites share a similar composition to early Earth (approximately 4.55 billion years ago) and contain a significant amount of hydrogen. Researchers from the University of Oxford have found that this hydrogen, bound to sulfur within the meteorites, could have reacted with oxygen on early Earth to produce abundant water. This suggests that Earth's water could have originated from within, rather than being delivered by collisions with icy bodies from the outer solar system.
These findings indicate that rocky planets forming in inner solar systems might naturally accumulate the building blocks for water. This could greatly increase the potential for habitable conditions in other planetary systems. However, some scientists remain cautious, noting that enstatite chondrites are susceptible to terrestrial contamination, which could affect the accuracy of hydrogen measurements.