A few months back, it was reported that China’s Chang’e 4 lunar rover, named Yutu-2, had stumbled across a mysterious substance on the Moon. Identified as a “gel-like” substance, its presence on the lunar surface has baffled scientists.
A mysterious substance
When the rover came upon the substance, the researchers postponed all other driving plans scheduled for the rover and started focusing all the tools at its disposal to analyze what the material was. The “gel” was found in one of the small impact craters on the surface. The rover examined the area with the Visible and Near-Infrared Spectrometer (VNIS) tool that detects light that reflects or scatters off materials. Scientists in charge of the mission have been unable to determine what the “gel” substance is other than that it has an “unusual color.”
Clive Neal, an expert in lunar geology, believes that the “gel-like” substance might actually just be glass. “The asteroidal or cometary shard that created this impact would have been moving at incredible speeds before it came to a staggering halt. It would have slammed into the moon with such extreme force that it would have generated exceedingly high temperatures and pressures at the impact site, melting rock at unfathomable speeds and leaving behind a myriad of molten pools. Exposed to the harsh, frigid environs of space, these would have cooled remarkably quickly, forming a glass,” according to Forbes.
Some also say that the Chinese report on the matter does not mention the word “gel,” but something like “glass” or “shiny.” A few media houses seem to have made a poor translation of the Chinese report. However, the fact remains that the newly discovered substance remains a mystery. Unfortunately, the rover is not equipped with advanced tools like the Alpha Particle X-Ray Spectrometer that was in the previous rover that landed in 2013. As such, it won’t be able to do any detailed chemical composition analysis to determine the nature of the “glue-like” substance.
The Chang’e 4 rover was launched in December 2018 and landed on the lunar surface the very next month. The Chinese space agency is expected to launch the Chang’e 5 mission by next year. This will be its first sample return mission to the Moon, with the vehicle bringing back around 2 kilos of lunar rock and soil samples back to Earth.
The crater mystery
In May this year, the rover had helped provide evidence on how the vast basin that the Chang’e 4 mission landed on, called the SPA basin, may have been formed. This was also done through the VNIS instrument. The 2,300 km-wide SPA basin covers almost a quarter of the lunar circumference. The entire basin is believed to be 3.9 billion years old, formed by a 170 km-wide asteroid collision.
“Early results from the rover’s Visible and Near-Infrared Spectrometer (VNIS) suggest the rocks contain minerals known as low-calcium (ortho) pyroxene and olivine. They fit the profile of rocks from the lunar mantle and suggest that the ancient impact that created the SPA drove right through the 50km-deep crust into the mantle,” according to the BBC.
Results of the analysis will allow scientists to study the mineralogical and chemical composition of the mantle in greater detail, something that was impossible till the VNIS results came out. This could even point toward the origin and development of the Moon.