Ancient asteroid strike in Australia "changed face of earth"

[Reuters]  A strike from a big asteroid more than 300 million years ago left a huge impact zone buried in Australia and changed the face of the earth, researchers said on Friday. "The dust and greenhouse gases released from the crater, the seismic shock and the initial fireball would have incinerated large parts of the earth," said Andrew Glikson, a visiting fellow at the Australian National University.