When most of us think about what shaped our planet, we probably picture volcanoes, earthquakes, and huge continents slowly drifting apart (or back together again) over millions or billions of years. We also know meteorite impacts were important; our crater-packed Moon is clear evidence of that.
But what if Earth’s geological story was also written further afield in the stars – specifically, in the spiral arms of our home galaxy, the Milky Way?
