Asteroid collision triggered ancient ice age

Scientists claim a massive asteroid collision may have filled the atmosphere with enough dust to trigger an ice age. They say sunlight-blocking dust remained in the sky for around two million years, effectively causing Earth to freeze. Scientists have long been puzzled by the cause of an ice age that took place 466 million years ago. Dust is constantly floating down to Earth from space, made from broken parts of asteroids and comets. Scientists believe Earth gains about 40,000 tons of extraterrestrial material every year. Through dating mechanisms, it's possible to verify that a large amount of dust fell around the same time as an ice age began. Not all sunlight would have been blocked – but enough to change Earth's climate. This allowed life to adapt "and even benefit" from the changes, sparking "an explosion of new species".