What killed the dinosaurs? No, it wasn’t the ice age, despite what Mr. Freeze would have you believe. Most scientists agree that a large impact event 66 million years ago was the cause, creating the famous Chicxulub impact crater in Mexico.
But a new study published in the journal Gondwana Research has proposed a rather more radical theory. A team of Japanese scientists has suggested that Earth may have passed through a dense interstellar cloud around the time the dinosaurs went extinct, leading to a “Nebula Winter” that caused a large amount of global cooling, ultimately wiping out most life on Earth.
http://www.iflscience.com/space/dino...rstellar-cloud