Study Suggests Earth Acquired Life’s Essential Elements from Inner Solar System
New geochemical modelling indicates Jupiter’s formation played a critical role in delivering nitrogen and phosphorus to the early Earth.
NASA-supported scientists have published a study in Science Advances suggesting that Earth acquired essential elements for life, specifically nitrogen and phosphorus, primarily from planetesimals in the inner solar system rather than outer solar system chondrites. The research indicates that Jupiter’s formation and gravitational influence played a critical role in distributing these chemical ingredients, creating a phosphorus-to-nitrogen ratio in the inner solar system that matches Earth’s current signature.
The study, led by Debjeet Pathak and senior author Rajdeep Dasgupta from Rice University, used laboratory experiments and geochemical models to reconstruct a map of P/N ratios across the early solar system. Researchers found that the first generation of planetesimals (source of iron meteorites) had higher P/N ratios in the outer solar system, while the second generation (source of chondrites) had higher ratios in the inner solar system.
The model suggests that as Jupiter formed and grew, it restricted the movement of phosphorus and nitrogen from the inner to the outer solar system, leaving inner solar system planetesimals with a higher P/N ratio. Geochemical accretion modeling shows Earth’s present-day P/N signature is best reproduced by inner solar system planetesimals, implying a minimal contribution from outer solar system chondrites.
The study raises the question of whether a life-essential element budget similar to Earth’s can be established without a Jupiter-like planet.
Dasgupta, of Rice University in Houston, noted that Jupiter’s presence and growth history seem to have played a critical role in determining the distribution of the basic chemical ingredients necessary for habitable worlds. He added that it remains an open question whether a similar budget can be established without a Jupiter-like planet in the population.
Lead author Pathak stated that the study suggests Earth acquired its inventory of phosphorus and nitrogen primarily from the inner solar system, without requiring a significant contribution from outer solar system chondrites.
The research provides new context for astrobiologists studying how and when the Earth became habitable. While there has been debate over whether chondrites from the outer solar system delivered these elements late in the planet’s formation, this work points to a different origin story driven by the early architecture of the solar system.
