The smallest planet in our Solar System may be hiding a big secret. Curious bright streaks on Mercury 's surface, doodled on its craters and slopes, are probably a sign of very recent geological activity, according to new models. The findings suggest that Mercury is far from being 'dead' or dull, as astronomers once supposed. Instead, our neighbor's 'hellscape' of a surface seems to be alive and kicking – geologically speaking, that is. Until recently, scientists had catalogued only a handful