PBS Eons has an episode on this: When the Earth Was Purple https://m.youtube.com/watch?v=IIA-k_bBcL0 https://m.youtube.com/watch?v=IIA-k_bBcL0 (This is great

PBS Eons has an episode on this: When the Earth Was Purple https://m.youtube.com/watch?v=IIA-k_bBcL0 https://m.youtube.com/watch?v=IIA-k_bBcL0 (This is great science channel. PBS should have continued to receive federal funding.)