China’s Yutu-2 probe has made another astonishing discovery on the far side of the moon. In the dry gray dust, Yutu-2′s panoramic camera captured two complete, translucent glass spheres.
The granules could record information about the moon’s history, including the composition of the moon’s mantle and impact events. Yutu-2 cannot obtain composition data, but this natural lunar marble could be an important target for future research.
In fact, glass is not uncommon on the Moon. The substance is formed when silicate materials are exposed to high temperatures, and both components are found throughout the Moon.
In the past, the Moon has experienced large-scale volcanic activity, leading to the formation of volcanic glass, and impacts of smaller objects such as meteorites have also caused intense heating, leading to the formation of glass.
A team of scientists led by Xiao Zhiyong, a planetary geologist at Sun Yat-sen University and the Chinese Academy of Sciences, believes the latter could be the material underlying the spheres observed by Yutu-2.
It is difficult to say for sure, however, because most of the glass found on the Moon is different in appearance from the spherules found by Yutu-2. There are many spheres on the Moon, but they are usually less than a millimeter in size.
On Earth, these tiny glass beads are formed during impacts that generate so much heat that the crust melts and sprays into the air. The molten material hardens and then falls back to earth, forming tiny glass beads.
The Yutu-2 sphere is much larger, between 15 and 25 millimeters in diameter. This alone is not enough to make them unique: during the Apollo 16 mission, glass spheres up to 40 mm in diameter were discovered on the far side of the Moon. The spheres were found in nearby craters and are also considered to be impact spheres.
But there are differences between the two findings. The distal sphere appears translucent and has a glassy sheen, Xiao and his colleagues explained. In addition to the two spheres that appeared translucent, they found four more spheres with the same sheen, but their transparency could not be confirmed.
Spherules have been found near new impact craters, which may indicate that they were formed during lunar meteorite impacts, although it is also possible that they already existed, were buried beneath the surface, and were simply dug up by the impact.
However, the team believes the most likely explanation is that they formed from a volcanic glass called anorthosite, which melted again during the impact, turning into translucent, rounded spherules.
”Overall, the unique morphology, geometry and local environment of the glass spheres are consistent with the action of anorthosite on glass,” the researchers write in their paper.
This could make these objects on the moon the same as tektites, pebble-sized glass objects that form when Earth material melts, bursts into the air, and then hardens into spheres when it falls back down. Like a larger version of those tiny spheres.
We can’t know for sure without studying their composition, but if they are lunar meteorites, they are likely fairly common on the lunar surface. The team says this opens up some tantalizing possibilities for future research.
”As this is the first discovery of macroscopic translucent glass spheres on the Moon, this study predicts that such spheres should be abundant in the lunar highlands, providing a promising sampling target to reveal the early impact history of the Moon,” they write.
Post time: Jan-17-2025