What is known about the comet that Rosetta will land on?
Comet 67P/Churyumov-Gerasimenko is a large, dirty snowball whose orbit around the Sun takes 6.6 years. Ground-based telescopes have observed 67P/Churyumov-Gerasimenko during almost all its appearances since its discovery in 1969. To acquire as much information as possible about the comet, ESA made a rigorous series of ground and space-based observations. These observations have provided us with a fairly reliable estimate of the comet’s size and shape – about four kilometres in diameter.
