Scientists from Rosetta’s OSIRIS team have discovered an extraordinary formation on the larger lobe of comet 67P/Churyumov-Gerasimenko in the Aker region. From a group of three boulders the largest one with a diameter of approximately 30 meters stands out: images obtained on 16 September 2014 from a distance of 29 kilometers with the help of Rosetta’s scientific imaging system OSIRIS show it to perch on the rim of a small depression. There seems to be only a very small contact area with the nucleus. Similar geological formations are found also on Earth. So-called balancing rocks touch the underground with only...