Scientists Debate Whether Earth's Oceans Came from Comets, Asteroids, or Were Homegrown
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By Robin George Andrews June 12, 2026
Crisp on the outside, thoughtful on the inside. A keeper.
Summary
The article explores the evolving scientific debate about the origin of Earth's oceans. Initially, scientists believed Earth's water arrived via comets or asteroids after the planet formed. However, new research suggests that Earth may have retained water from its formation, stored deep within the mantle in minerals like ringwoodite, and gradually released it through volcanic activity. This "homegrown" hypothesis challenges the long-held extraterrestrial delivery theories and has implications for understanding planetary formation and the potential for water on exoplanets.
Key quotes
· 3 pulledAnd it is not darkness that unites us, not the cold distance of space, but the offering of water, each drop of rain, each rivulet, each pulse, each vein.
For decades, NASA's exploration of the solar system has been dominated by the search for water.
At first, scientists thought Earth's water came from comets. Then, asteroids. Now, they wonder if Earth's water is homegrown.
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