These high cliffs occur on the surface of a comet. They were discovered to be part of the dark nucleus of Comet Churyumov–Gerasimenko (CG) by Rosetta, a robotic spacecraft launched by ESA which began orbiting the comet in early August.
The European Rosetta spacecraft's Philae lander aims to be the first probe ever to safely land on a comet. Here's how to land on a spinning ice mountain in space. - Credit: By Karl Tate, Infographics Artist
An artist's impression handout image by the European Space Agency shows the Rosetta orbiter deploying the Philae lander to comet Credit: Reuters/European Space Agency-C. Carreau/ATG medialab/Handout via Reuters
A Stunning Look at the Cliffs of Comet by NANCY ATKINSON on DECEMBER 2014 The Cliffs of Churyumov-Gerasimenko: an enhanced and procosessed crop of an image from Rosetta's navcam. Credits: ESA/Rosetta/NAVCAM, processing by Stuart Atkinson.
This single frame Rosetta navigation camera image of Comet was taken on 25 March 2015 from a distance of km from the comet centre. The image has a resolution of m/pixel; this processed, cropped version measures km across.