Scientists have identified the world's oldest asteroid crater in Australia, saying that it may explain how the planet was lifted from an ice age.
The asteroid hit Yarrabubba in Western Australia about 2.2 billion years ago - making the crater about half the age of Earth.
The scientists say the find is exciting because it could account for a warming event during that era.
Scientists using computer modelling, the team calculated that the asteroid struck a kilometres-thick ice sheet covering the Earth. The event would have released huge volumes of water vapour, a greenhouse gas, into the atmosphere.