Sulfur: The Catalyst for Earth's First Water
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Loading... - Brian Lyus
- 19 Jul 2024
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A new study reveals that sulfur, an element not present in H2O, played a pivotal role in Earth's initial water formation. This finding supports a similar claim made last year, suggesting that Earth possessed the necessary components to generate its own water, eliminating the need for extraterrestrial delivery.
Despite forming in an intensely hot region around the newborn sun, Earth managed to retain water. Two separate studies of enstatite chondrites, a specific type of meteorite, indicate that hydrogen, a key water component, arrived on Earth bonded with sulfur. This bond allowed hydrogen to withstand high temperatures and later combine with oxygen, Earth's most abundant crustal element, to form water.
Alessandro Morbidelli, a planetary scientist at the Côte d’Azur Observatory in Nice, France, notes the compelling nature of these findings. The four planets closest to the sun, including Earth, formed in the solar nebula's inner, densely heated region. This intense heat theoretically should have left Earth dry, leading researchers to hypothesize that water arrived via ice-bearing asteroids and comets from the outer solar system.
However, in 2020, a study found that hydrogen existed in enstatite chondrites, suggesting that Earth's building blocks had hydrogen from the beginning. Despite initial skepticism about contamination, subsequent research demonstrated that the hydrogen in these meteorites was bonded to sulfur. Recently, another team identified that most of this hydrogen resides in pyrrhotite, an iron sulfide mineral, confirming its extraterrestrial origin and eliminating contamination concerns.
Morbidelli describes this as a paradigm shift, explaining that Earth did not accrue water directly but instead accumulated hydrogen and oxygen in different minerals, which later combined to form water. Edward Young, a UCLA cosmochemist, adds that early Earth, with its molten surface and magma ocean, facilitated this combination, as oxygen was plentiful in the crust.
Young posits that while Earth's building blocks provided significant hydrogen, additional hydrogen likely came from the solar nebula's molecular hydrogen gas and icy objects that impacted Earth. This multifaceted origin of water has profound implications for exobiology. Morbidelli highlights that sulfur, the tenth most abundant element in the cosmos, could enable rocky planets in other solar systems to generate water, even without icy asteroids or comets. This process could set the stage for potential life development on these planets.
These discoveries underscore the crucial role sulfur played in Earth's water genesis and its broader implications for the potential of life beyond our planet.
