Meteroites carbon dating
(Michael Holly, Creative Services/University of Alberta/NASA)The chemical building blocks of RNA molecules, called nucleobases, have been found in carbon-rich meteorites.
The study authored by Ben Pearce, left, and Ralph Pudritz, suggests there were enough meteorites carrying the raw ingredients for RNA splashing into enough ponds in the early Earth to produce ample opportunities for RNA to form. The chemical building blocks of RNA molecules are called nucleobases, and they’ve been found in carbon-rich meteorites such as the Tagish Lake meteorite, which was found on a frozen lake in British Columbia in 2000.In 2011, data from ESA's Herschel Space Observatory revealed that Kuiper Belt comet 103P/Hartley 2 had a deuterium-to-hydrogen ratio "that matched terrestrial water's perfectly," Altwegg said during a news conference Tuesday (Dec. "The Hartley 2 measurement — that was a real big surprise."Now, Rosetta has provided data from Comet 67P/C-G, another Kuiper Belt comet.However, Rosetta has discovered that this comet possesses an even higher deuterium-to-hydrogen ratio than seen in Oort Cloud comets — three times the amount of heavy water compared to normal water as Earth has.Otherwise, the ingredients would leak right out of the pond into the ground or be destroyed by the sun's ultraviolet rays or chemical reaction with the water itself before they could form RNA, the researchers found.The team says this is the first time anyone has assembled together information about the conditions on the early Earth and experiments on chemically building RNA, filled the gaps by calculating the physics that they would have undergone through the process, and put all the puzzle pieces together to see whether it was feasible for life to get its start this way.