The team who study Rosetta's OSIRIS imaging system discovered the change when they started adjusting the exposure levels of the images taken.
Originally dust trails had been localised to the comet's weakest point, the neck. However recent pictures have shown an increase in activity spreading across the entire surface of the spinning rock.
Astronomers have long suspected that as a comet gets to within 300 million kilometre of the Sun it would start showing increased levels of activity however 67P/Churyumov-Gerasimenko is still over 450 million kilometres away.
It's believed that despite the activity it won't affect the ESA's plan to land the Philae spacecraft onto the surface of the comet.Suggest a correction