Scientists have long understood that Earth's geological evolution is influenced by extraterrestrial factors. As they state in their paper, Earth's crust was shaped by the impact of meteorites as it orbited the center of the Milky Way. As Prof. Kirkland explained in a Curtin University release:Tiny, durable minerals called zircon crystals provided a unique archive of Earth’s interaction with the galaxy. Their findings show that Earth's geological evolution cannot be understood in isolation and suggest that astrophysical processes on a galactic scale have directly influenced geological history. Further Reading: Curtin University, Physical Review Research