Here's an excellent interview of Jonti Horner by John Batchelor on this topic (free podcast): https://audioboom.com/posts/4827661-mass-extinction-and-the-struc

Here's an excellent interview of Jonti Horner by John Batchelor on this topic (free podcast): https://audioboom.com/posts/4827661-mass-extinction-and-the-structure-of-the-milky-way-joint-horner?t=0 https://audioboom.com/posts/4827661-mass-extinction-and-the-...