of china Chang’e-6 The mission is currently on its way to retrieve a material sample from the far side. moonIt will test theories about why the near and far sides of the Moon are so different.
Have Launched on May 3 Chang’e-6 is expected to land in the even larger Apollo double-ring impact basin in early June. South Pole–Aitken basin (SPA). The enormous SPA is the biggest impact feature of its kind. solar systemSpanning an area of 2,400 x 2,050 kilometers (1,490 x 1,270 miles); It was formed approximately 4.3 billion years ago. A lot early in the history of the solar system. Although Apollo is younger, it is also the largest domain to be superimposed on the SPA. Apollo has a double-ring structure, with an inner ring of mountain peaks measuring 247 kilometers (153 miles) in diameter and an outer ring approximately 492 kilometers (305 miles) in diameter.
Relating to: China’s Chang’e 6 mission to collect samples from the far side of the moon enters lunar orbit (video)
Chang’e-6, the first sample return mission to the far side, aims to return approximately 2 kilograms (4.4 pounds) of valuable lunar material to Earth. The far side is a relatively unknown place; The fact that we cannot see it from Earth further adds to its mystery. It was first photographed by the Soviet Luna 3 spacecraft in 1959. With this photo in hand, scientists around the world were amazed to learn how different the far side of the moon looked compared to our side. similar. While there are many craters on both the near and far sides, very large craters are also seen on the near side. Volcanic plains called Ay MariaCreating impressions similar to the “man on the moon” shape and occupying something like 31% of the entire immediate area.
Meanwhile, the far side is the exact opposite. Volcanic plains cover only about 1%.
So how did the near side and far side become so different? The thickness of the shell seems to be a factor. As a matter of fact, in 2011 NASA STAMP (Gravity Recovery and Interior Laboratory) mission found that the crust of the far side is on average 20 kilometers (12 miles) thicker than the crust of the near side.
The reason for this is thought to date back to the formation of our moon from debris ejected when a Mars-sized protoplanet crashed into the Earth approximately 4.5 billion years ago. The moon was tidally locked as it coalesced from debris around the injured Earth, meaning it would always show the same face to our planet. Due to the massive impact, the Earth’s surface melted completely and radiated heat to the near side of the moon, keeping itself molten for longer. Scientists suggest that the rock would evaporate on the near side and condense on the cooler far side, making the crust on the far side thicker.
“The key finding suggests that the crustal thickness difference between the near and far side may be the main cause of the Moon’s asymmetric volcanism,” Yuqi Qian from the University of Hong Kong said in a statement. said.
Qian is one of the lead authors of a new study that suggests sample material brought to Earth by Chang’e-6 could test this theory.
The logic is as follows.
Where the lunar crust is thick, such as most of the far side, magma rising through cracks in the rock cannot escape to the surface. Where the crust is thin, such as on the near side, these cracks can actually penetrate magma and cause lava to erupt.
SPA and the Apollo basin present some contradictions, even though they are both on the far side of the Moon. This is because they have penetrated deeply into the Moon’s crust, and the crust at the base of these massive impact zones is thinner than that of the Moon. somewhere else on the far side. And yes, there are volcanic plains in these basins, but still only 5% of their area is covered by basaltic lava flows. This limited amount of volcanism seems contrary to the idea that crustal thickness is what determines volcanic activity; a long-known paradox in lunar science.
An alternative possibility suggests that the near side may contain more radioactive elements than the far side. These elements may have produced heat, causing the lower mantle to melt, resulting in much more magma as well as a thinner crust on the near side. Hence more volcanism.
However, Chang’e-6 could land on one of several volcanic plains on the far side, returning samples to test such theories directly. In particular, the Apollo basin region where Chang’e-6 will land contains various materials that require research.
Some evidence also indicates that two major volcanic eruptions took place in the region. Scientists believe that about 3.35 billion years ago, the entire region was covered with magma containing low amounts of titanium. The other, which formed 3.07 billion years ago, probably had titanium-rich magma and was more localized; It was erupting near the Chaffee S crater (named after Roger Chaffee, one of the astronauts who died tragically). Apollo 1 disaster) and spreads eastward with decreasing thickness.
The new study suggests that sampling close to Chaffee S would provide the greatest scientific benefits. There is titanium-rich basalt in the upper part of this region, titanium-poor basalt in the lower part and various eruptive fragments resulting from impacts.
“Various sample sources will provide important information towards resolving a number of lunar scientific questions hidden in the Apollo basin,” said Joseph Michalski and Hong Kongers, who co-authored the new study with Yuqi Qian. colleague Guochun Zhao and researchers from China, Germany, and elsewhere in the United States.
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These various samples can tell scientists something about the magmatic processes occurring on the far side, and comparing them with samples from the near side returned by the Apollo missions may hold the answer to why volcanism is so limited on the far side.
“The result of our research is a great contribution to the Chang’e-6 lunar mission,” Zhao said. “It provides a geological framework for a complete understanding of the soon-to-be-returned Chang’e-6 samples and will be an important reference for upcoming sample analysis for Chinese scientists.”
The team’s article was published in the magazine Earth and Planetary Science Letters; You can stay tuned to Space.com for more updates on the Chang’e-6 mission.