Earth Planet

A massive bombardment of meteorites billions of years ago could have brought in enough water and carbon dioxide to jump-start the chemistry that let the Earth develop into the garden spot of our solar system. By studying meteorites and other evidence from this bombardment, a team of researchers at Imperial College in England has calculated that the meteorites could have carried in as much as 10 billion tons of water vapor and carbon dioxide to the young Earth every year for millions of years.