A new study has shown that Comet 67P/Churyumov-Gerasimenko has frozen water just beneath its surface, which occasionally becomes exposed as a result of geological activity. The news shouldn't come as much of a surprise: we already knew that there was water on the comet. A previous analysis of 67P showed that the cloud of gas surrounding the comet, known as the coma, contained water vapour, carbon dioxide and carbon monoxide. Microscopic ice grains had also been observed on its surface, a result of water vapour being ejected from inside the comet.
The new study, carried out by researchers at the National Institute for Astrophysics in Rome and published in Nature, used data from Rosetta's infrared detector, called VIRTIS, to study the face of the comet. The team found patches of grains of ice, each around a millimetre in size, that had been exposed by fallen cliff faces. It's currently unclear how they might have formed.
The researchers hope that by studying the different forms of water present on and around the comet they can develop a better understanding of its history.
Image by NASA