by of China Change-6 mission, currently on its way to obtain a sample of material from beyond the moonto test theories why the lunar and distant side are so different.
At launched on 3 May, Chang’e-6 is expected to land in early June within Apollo’s double ring impact basin, which is within the even larger area South Pole – Aitken basin (SPA). The huge SPA is the most impactful feature of its kind in the Solar system, covering 2,400 by 2,050 kilometers (1,490 by 1,270 miles) in area; it was formed about 4.3 billion years ago, that is very early in the history of the solar system. Although Apollo is younger, it is the most influential site to superimpose on the SPA. Apollo sports a double-ring structure, with an inner ring of mountain peaks with a diameter of 247 kilometers (153 miles) and an outer ring about 492 kilometers (305 miles) across.
Related: China’s Chang’e 6 mission to collect samples from the far side of the moon enters lunar orbit (video)
As the first sample-return mission to the far side, Chang’e-6 aims to return about 2 kilograms (4.4 pounds) of precious lunar material back to Earth. The far side is a relatively unknown place; its mystery is also added to by the fact that we cannot see it from Earth. It was not photographed for the first time by the Soviet spacecraft Luna 3 in 1959. And with this photo in hand, scientists around the world were surprised to learn how different the far side of the moon looks compared to our side. familiar with. While the near and far sides sport numerous craters, the near side is also a huge display, volcanic plains known as maria moonswhich creates an impression similar to the “man on the moon” shape and covers something like 31% of the total near-side area.
Meanwhile, the other side is quite the opposite. Only about 1% is covered by volcanic plains.
So how did the near side and the far side become so different? Well, the thickness of the crust seems to be a factor. In fact, in 2011, NASA on GRAIL (Gravity and Interior Recovery Laboratory) mission, it was found that, on average, the crust on the far side is 20 kilometers (12 miles) thicker than the crust on the near side.
The reason for this is thought to go all the way back to when our moon was formed from debris thrown out when a Mars-sized protaplanet hit Earth about 4.5 billion years ago. As the moon gathered from the debris around a wounded Earth, it became tidally locked, meaning it would always show the same face to our planet. The Earth’s surface was completely melted by the massive impact, and it radiated heat to the side of the moon, which itself kept it melted longer. Rock would vaporize on the near side and condense on the cooler far side, according to scientists, making the crust on the far side thicker.
“The fundamental finding indicates that the crust thickness discrepancy between the near side and the far side may be the main cause of asymmetric lunar volcanism,” said Yuqi Qian from the University of Hong Kong in a statement.
Qian is one of the lead authors of a new study that suggests that sample material returned to Earth by Chang’e-6 could test this theory.
The logic is as follows.
Where the lunar crust is thick, for example on most of the far side, magma rising through fractures in the rock cannot break through to the surface. When the crust is thin, such as on the adjacent side, these fractures can allow magma to break through, and lava can erupt.
SPA and the Apollo basin, despite both being on the lunar side, have some contradictions, however. another place on the other side. And yes, there are volcanic plains within these basins, but still, only 5% of their area is covered by basaltic lava flows. This limited amount of volcanism seems to contradict the idea that volcanic activity is determined by the thickness of the crust – a long-known paradox in lunar science.
Another possibility suggests that there may be more radioactive elements on the near side than on the far side. These elements may have produced heat, causing the lower mantle to melt and resulting in much more magma and a thinner crust on the other side. So, more volcanism.
However, by landing on one of the few volcanic plains on the far side, Chang’e-6 can bring back samples to directly test such theories. In particular, there are diverse topics that should be investigated in the region of the Apollo basin where Chang’e-6 will land.
Some evidence also shows that there were two major volcanic eruptions in the region. Only, about 3.35 billion years ago, scientists believe that the entire region would have been covered in magma with a low abundance of titanium. The other, which occurred 3.07 billion years ago, probably contained titanium-rich magma and was more localized, erupting near the Chaffee S crater (named after Roger Chaffee, one of the astronauts who died tragically in Slovakia). Apollo 1 disaster) and spreading eastward with reduced thickness.
The new study suggests that obtaining a sample from near Chaffee S. This region has titanium-rich basalt on top, titanium-poor basalt below and various pieces of ejecta from the impacts.
“Different sample sources would provide important insights into solving a series of lunar scientific questions hidden in the Apollo basin,” said Joseph Michalski of Hong Kong, who co-authored the new study with Yuqi Qian, also from Hong Kong. colleague Guochun Zhao and researchers from other parts of China, Germany and the United States.
Related Stories:
— This is what China’s 1st lunar landing with astronauts would look like (video)
— China’s next moon missions get the green light
— China opens Chang’e 5 lunar samples to international researchers
These diverse samples could tell scientists something about the magical processes that took place in the beyond, and by comparing them with nearby samples returned by the Apollo missions, the answer could be found as to with why the volcanism was so limited laterally.
“The result of our research is a major contribution to the Chang’e-6 lunar mission,” Zhao said. “It sets a geological framework to fully understand the Chang’e-6 samples returned early and will serve as a key reference for the upcoming sample analysis for Chinese scientists.”
The team’s paper was published in the journal Geography and Geography Letters; you can follow Space.com for additional updates on the Chang’e-6 mission.
