Comets probably didn’t deliver life’s building blocks to Earth

Science News reports that simulations found comet impacts capable of delivering a meaningful amount of hydrogen cyanide to Earth’s surface were extremely unlikely. To keep the molecule intact, a comet would have to be larger than 100 meters across, move slowly and strike at an oblique angle. The study doesn’t rule out comet delivery entirely, but challenges the idea that comets supplied life’s chemical building blocks.