The Rhythm of the Spheres

This kilometer high cliff occurs on the surface of a comet. It was discovered on the dark nucleus of Comet Churyumov - Gerasimenko (CG) by Rosetta , a robotic spacecraft launched by ESA , which orbited the comet from 2014 to 2016. The ragged cliff, as featured here , was imaged by Rosetta early in its mission. Although towering about one kilometer high, the low surface gravity of Comet CG would likely make a jump from the cliffs by a human survivable. At the foot of the cliffs is relatively smooth terrain dotted with boulders as large as 20 meters across. Data from Rosetta indicates that the ice in Comet CG has a significantly different deuterium fraction -- and hence likely a different origin -- than the water in Earth's oceans. The probe was named after the Rosetta Stone , a rock slab featuring the same text written in three different languages that helped humanity decipher ancient Egyptian writing.