Study: 20-Million-Year Meteorite Shower Turned Earth Warm & Wet

A shower of millions of rocks from space that collided with Mars, the Earth, and the moon about four billion years ago could have warmed our planet and made it wetter, say researchers. That's what scientists found when they heated ancient rocks like those that hit the Earth billions of years ago and measured the carbon dioxide and water that was released, according to a study published in the journal Geochimica et Cosmochimica Acta. Scientists have long suspected that the necessary materials for life could have come from outer space, and the study suggests how and when the Earth might have received these life-giving ingredients. During the 20-million-year-long meteor shower known as the Late Heavy Bombardment, the rocks that hurtled towards Earth would have been heated to extremely high temperatures as they entered the atmosphere.