Overview

• A Curtin University team led by Chris Kirkland reports in Physical Review Research that chemical signals in ancient zircons align with the Solar System’s transits through the Milky Way’s spiral arms.
• The analysis links spikes in zircon oxygen-isotope variability to periods of higher neutral hydrogen density that trace the galaxy’s arms, recurring roughly every 180–200 million years.
• The authors propose that gravitational disturbances in these regions sent comets and asteroids inward, producing impact-driven melting that generated more chemically complex magmas.
• Zircons serve as durable time capsules of magmatic conditions, preserving a deep-time record that can persist even when impact craters are erased by erosion and plate tectonics.
• The team cautions that the findings show correlation rather than causation, noting uncertainties in Earth’s rock record and the Solar System’s galactic path that require further testing and replication.