Few countries have ever successfully landed on the surface of the moon, and one of the countries to do so was China with the Yutu-2 rover. That rover found something interesting on the surface of the moon that has puzzled scientists, and the mystery has finally been solved. Inside a small impact crater on the far side of the moon, Yutu-2 discovered a strange and shiny gel-like substance.
Scientists have now determined what that strange material was using image analysis and comparison photos with Apollo samples from Earth. The shiny material was rock. Specifically, it was a type of rock that was melted together, presumably in the heat of a meteorite impact to form a dark green, glossy, glassy mass.
A research paper on the subject described the material as a dark greenish, and glistening impact melt breccia on the floor of the Von Karman crater within the South Pole Aitken basin on the lunar Far Side. The peculiar rock is formed by impact-generated welding, cementing, and agglutinating of lunar regolith and breccia. The rock was imaged by Yutu-2 in late July 2019 and revealed to the world the following month.
When the picture was released publicly, it was described as gel-like. However, other scientists speculated that the materials likely not moist at all as the lunar landscape is arid and dusty. Near-Infrared Imaging Spectrometer proved very helpful in the final identification of the material. The material was very similar to a pair of samples retrieved by the Apollo 15 and 17 missions.
Though samples are known as Lunar Sample 15466 and Lunar Sample 70019, both samples were retrieved from impact craters and classified as breccia. Breccia is a type of rock made up of chunks of rocks cemented together by finer material. The chunks were lunar regolith, and the cement was black glass.