Overview
- ETH Zurich researchers Craig Walton and Maria Schönbächler report in Nature Astronomy that a rocky planet’s initial oxygen budget sets whether phosphorus and nitrogen remain available near the surface.
- Their simulations show that too little oxygen drives phosphorus into the metal core, whereas too much oxygen allows nitrogen to escape from magma into space.
- Earth falls within a narrow chemical Goldilocks zone that retained both elements in accessible reservoirs during formation.
- Applying the model to our solar system, the authors indicate Mars likely formed outside this range, limiting near-surface nitrogen and phosphorus despite past water.
- The study urges astronomers to prioritize targets using host-star elemental abundances as a proxy for planetary starting chemistry, suggesting truly habitable rocky worlds may be rarer and noting that observational application remains indirect.