China’s Yutu-2 rover has detected two intact spheres of translucent glass about 3 centimeters thick on the ‘far side’ of the Moon. The images show what appear to be two glass spheres as if they were lunar marbles.
Is it an extraordinary find?
Not really. Small glass “spheres” are quite common on our satellite, although they are typically about 3 millimeters in diameter. These are especially large. These glass spheres form when silicate material is subjected to high temperatures, and both ingredients are readily available on the Moon.
Meteorite collisions or volcanic activity
In essence, the Moon had a past of great volcanic activity that led to the formation of volcanic glass ; in the same way, the impact of smaller objects, such as meteorites, also generate intense heat, which results in the formation of glass .
“Glass is ubiquitous in lunar regolith, and volcanism and hypervelocity impacts are the main formation mechanisms of lunar glass,” the team clarifies.
As we say, the discovery, published in the journal Science Bulletin, comes from the other side of the Moon, but it agrees with the darkest spheres discovered by the Apollo astronauts decades ago, among other things. But unlike the spheres found on the near side of the Moon, these are translucent, a unique light brown color.
“The globules simply surprise us as they are unique to the Moon,” said Zhiyong Xiao, an associate professor at Sun Yat-sen University’s Planetary Environmental and Astrobiological Research Laboratory and lead author of the study, in a press release.
Chinese researchers suggest that these types of spheres could be common on the far side of the Moon. If this were the case, it could be an incredibly valuable resource for future lunar colonies. We could use glass for building materials or tools. Moreover, experts believe that the most likely explanation for its formation is based on a volcanic glass called anorthosite that melted with the impact of a meteorite, reforming into translucent spherical globes. In this way, they would be like the terrestrial tektites.
“Taken together, the peculiar morphology, geometry, and local context of the glass globules are consistent with anorthositic impact glasses,” the researchers write in their paper.
“The globules were recently formed or exposed, as evidenced by their intact shapes and surface exposure,” the experts say. However, the exact composition of the glass has not yet been determined.
The rover detected the spheres along the surface in the 700 meters traveled by the vehicle as it moved away from the Chang’e-4 lander. This walk took him 12 lunar days, each 14 Earth days long, followed by equally long nights. Because Yutu-2 is solar powered, it has to be constantly ‘sleeping’ when there is no sunlight. Unfortunately, Yutu-2 did not have the opportunity to analyze these objects, but it is clear that they will be the focus of investigation in future explorations.
A rover on the hunt for ‘lunar mysteries’
This is not the first time that Yutu-2 has encountered strange features on the Moon: last year, it sent back photos to Earth of a ‘mystery hut’ on the horizon. However, a closer inspection of the “mysterious object” revealed that it was only a rock that many found similar to a rabbit.
Chang’e 4 was China’s fourth mission to the Moon and the second to send a rover. And it will not be the last: Chang’e 6, 7 and 8 are already approved and will be launched from 2024.
