The path of comet 67P/Churyumov-Gerasimenko in October 2013

This image shows the path of 4-kilometre diameter comet 67P/Churyumov-Gerasimenko, last observed on 5 October 2013 by ESO's Very Large Telescope (VLT) when the comet was around 500 million kilometres away — before it passed behind the Sun and out of view from Earth's perspective.

Viewed against a crowded star field towards the centre of the Milky Way, the comet was still so far from the Sun that the icy nucleus was not releasing any gas or dust, and appeared as a simple spot (potw1403b). As it approaches the Sun, its surface will heat up and its ices will sublimate, dragging dust out to form a tail. This image shows the star field with the track of the comet marked with a line.

The observations mark the start of a close collaboration between ESA and ESO to monitor the comet from the ground during Rosetta's encounter with 67P/CG later this year. Rosetta was launched in 2004 and aims to explore the surface of the comet, deploying a lander down onto 67P/CG to see what its surface is like.