2025/07/23 by C. L. Kirkland, Phil J. Sutton · 1 voice
Physics and Astronomy · Environmental Science · #Astro and Planetary Science #Methane Hydrates and Related Phenomena #Planetary Science and Exploration
paper · doi:10.1103/98c3-d9j2
openalex publication_date 2025/07/23 · openalex created_date 2025/07/23 · openalex updated_date 2026/07/03
Neutral hydrogen (HI) is fundamental for tracing spiral structure in galaxies, including the Milky Way, through its 21-cm emission line, revealing features otherwise obscured by dust and gas. However, much of the Milky Way remains poorly resolved due to the Solar System’s embedded location within the galactic disk. Here, we present the first direct comparison between zircon oxygen isotope kurtosis, a terrestrial deep time record, and spatial variations in HI density along the Solar System’s galactic orbit. Significant correlations between Earth’s magmatic zircon oxygen isotope kurtosis and HI density in spiral arms suggest astrophysical influences on Earth’s crustal evolution. Peaks in HI density near the Scutum-Centaurus and Perseus spiral arms are consistent with the hypothesis that periodic disruptions of the Oort cloud during galactic arm crossings increased impact rates on Earth. These periods of elevated impact flux may have contributed substantial thermal energy, leading to more variable magmatic petrogenesis. This variability is recorded by zircon oxygen isotopes, a proxy sensitive to the depth of crustal melting and the degree of interaction with surface-derived water. These results provide new insights into the interplay between galactic-scale processes and Earth’s geological history, arguing for consideration of astrophysical drivers of planetary evolution.