The theory that comets successfully delivered the molecular building blocks for life on Earth is a long-standing one, since comets are known to carry many of these molecules. However, a new study challenges this idea. The researchers, led by the University of Cambridge, found the cometary delivery of these building blocks would be—at best—a 'one-off fluke,' and not the steady rain of prebiotic molecules that had been theorized. Using computer modeling, the researchers determined that comets t...