LUBBOCK, Texas, Oct. 29 (UPI) -- A Texas Tech University paleontologist says the beginning of life on Earth may have rained from the skies and been "cooked" in impact craters.
Sankar Chatterjee said the suggestion comes from connecting theories on chemical evolution with evidence related to our planet's early geology.
Regular and heavy bombardment of Earth's surface by comets and meteorites during its formative years 4 billion years ago left behind large craters that not only contained water and the basic chemical building blocks for life, but also became the perfect crucible to concentrate and "cook" these chemicals to create the first simple organisms, he suggested.
"When the Earth formed some 4.5 billion years ago, it was a sterile planet inhospitable to living organisms," Chatterjee said. "It was a seething cauldron of erupting volcanoes, raining meteors and hot, noxious gasses.
"One billion years later, it was a placid, watery planet teeming with microbial life -- the ancestors to all living things."
Chatterjee said his study of three sites containing the world's oldest fossils suggests the first single-celled organisms formed in hydrothermal crater basins.
Meteorites punching through the Earth's crust created volcanically driven geothermal vents and also brought the basic building blocks of life that could be concentrated and polymerized in the crater basins, he said.
"The emergence of the first cells on the early Earth was the culmination of a long history of prior chemical, geological and cosmic processes," he said.