At www.sciencenews.org/article/rosetta-may-have-spotted-comet’s-primordial-… … the rugged terrain of Comet Churyumov-Gerasimenko was the subject of a talk at the 2014 AGU annual meeting in San Francisco (December, 2014). It seems an onboard instrument has been taking some very close up photographs of the surface of the comet and this has revealed is is not a dirty snowball. Well, who'd have guessed that. More interesting, is the images also show cliffs on the comet that are 10s and 100s of metres in height – together with mysterious pits. These can be long as a football field and appear to be venting gases into space.