There was a 2013 paper titled "Mass Extinction and the Structure of the Milky Way" that you might find interesting: https://arxiv.org/abs/1309.4838 https://arxi

There was a 2013 paper titled "Mass Extinction and the Structure of the Milky Way" that you might find interesting: https://arxiv.org/abs/1309.4838 https://arxiv.org/abs/1309.4838 - I don't know if there have been any significant follow ups since it published. Basically our galaxy is a spiral galaxy with four arms, and it's rotating. The center moves slower than the outside, and our sun's orbit is near the inner rim of the Orion arm. We orbit the galaxy roughly every 240 million years and in that time we cross the dense galactic arms every so often (arms aren't symmetrical). The paper: "A correlation was found between the times at which the Sun crosses the spiral arms and six known mass extinction events."