The Optical Spectroscopic and Infrared Remote Imaging System (OSIRIS) camera on board Rosetta observed Earth during its swing-by last night.
This image was taken with the OSIRIS Wide Angle Camera (WAC) at 19:45 CET, about 2 hours before the closest approach of the spacecraft to Earth. At the time, Rosetta was about 80000 km above the Indian Ocean where the local time approached midnight (the angle between Sun, Earth and Rosetta was about 160°).
Islands of artificial lights created by human habitation are sparsely distributed over the part of the globe seen in the picture.
The image was taken with a five-second exposure of the WAC with the red filter.