A new study published in the journal Nature suggests that unmelted, or chondritic, meteorites were the primary source of water on Earth. Led by the University of Maryland Assistant Professor of Geology Megan Newcombe, the researchers analyzed melted meteorites and found extremely low water content. They ruled them out as the primary source of Earth’s water, which could have important implications for the search for water and life on other planets.
The researchers analyzed seven melted meteorites that crashed into Earth billions of years after splintering from at least five planetesimals. In a process known as melting, many of these planetesimals were heated up by the decay of radioactive elements in the early solar system’s history, causing them to separate into layers with a crust, mantle, and core.
After analyzing the achondrite meteorite samples, researchers discovered that water comprised less than two-millionths of their mass. This means that the heating and melting of planetesimals leads to near-total water loss, regardless of where they originated in the solar system and how much water they started with.
Newcombe said their findings have applications beyond geology. Scientists of many disciplines- especially exoplanet researchers- are interested in the origin of Earth’s water because of its deep connections with life.
References
- Newcombe, M. E., Nielsen, S. G., Peterson, L. D., Wang, J., Alexander, C. M. O., Sarafian, A. R., Shimizu, K., Nittler, L. R., & Irving, A. J. (2023). Degassing of early-formed planetesimals restricted water delivery to Earth. Nature. https://doi.org/10.1038/s41586-023-05721-5
- Nunez, E. (2023, March 15). Where Did Earth’s Water Come From? Not Melted Meteorites, According to Scientists. University of Maryland College of Computer, Mathematical, and Natural Sciences; University of Maryland. https://cmns.umd.edu/news-events/news/where-did-earths-water-come-not-melted-meteorites-according-scientists
