Mercury: The Ashtray of the Solar System? by SciFri published on 2015-04-03T21:59:07Z More at http://scifri.me/hwwiwx Scientists have been puzzled by why the surface of Mercury reflects such a small amount of light. Reporting in Nature Geoscience, a team of researchers hypothesize that the planet could be covered in carbon left by passing comets. “That carbon acts like a stealth darkening agent…like an invisible paint,” says Peter Schultz, a planetary geologist and co-author on the study. Genre Science Comment by Helen sound 2016-10-19T18:49:48Z