https://www.scientificamerican.com/article/asteroid-dust-triggered-an-explosion-of-life-on-ancient-earth/ > Consider the possibility that an asteroid may have transformed the picture of life on Earth—but forget the dinosaurs and the massive crater, and rewind an extra 400 million years from that dramatic moment. > Back then, life was primarily an oceanic affair and backbones were the latest in arrival on the anatomy scene. But unlike the asteroid that killed the dinosaurs 66 million years ago, this earlier space rock never made it to Earth. Instead, a collision in the asteroid belt flooded the solar system with so much dust  that, given some other changes at the time, allowed life on Earth to flourish, new research suggests.