Melted impact gap and surrounding context Credit: CNSA, CLEP and AIR
The unusual glowing dark greenish-green substance in a crater on the other side of the moon has sparked widespread interest after its discovery by the Chang’e-4 rover in July 2019.
A research team led by Prof. Di Kaichang of the China Academy of Sciences Aerospace Information Research Institute (AIR) and his collaborators analyzed the substance in detail using multiple data sets from the vehicle’s panoramic camera. scanner (Pancam), risk prevention camera (Hazcam), and the visible and near infrared spectrometer (VNIS).
The researchers found that the unusual substance is actually an impact fusion gap, and the provenance of the rover measured around the regolith could originate from a differentiated fusion group or set of igneous rocks. Their findings were published in Letters of the Earth and Planetary Science.
China’s Chang’e-4 probe, which includes a lander and a rover, successfully landed inside the 185-kilometer-wide Von Kármán crater within the South Pole-Aitken (SPA) basin on January 3, 2019, making the first squishy to be landing on the far lunar side.
The gelatinous substance was discovered in a crater on the eighth lunar day of the rover’s mission. Detailed measurements of the gap and the surrounding regolith were made during the ninth lunar day.
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Photos of samples of melted lunar impact gap Credit: NASA and AIR
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Hazcam images show rover locations Credit: CNSA, CLEP and AIR
The discovered gap, measuring 52 by 16 centimeters, resembles the lunar impact melt gap samples 15466 and 70019 returned by the Apollo missions. It was formed by welding generated by impact, cementing and agglutination of lunar regoliths and gaps.
The clods surrounding the crater that houses the gap were crushed into regolith powder by the rover’s wheels, indicating that the regolith may compact slightly and become blocked and friable. The spectral disintegration results based on the Hapke model showed that plagioclase was abundant and that pyroxene and olivine had almost equal fractions, indicating that regolith was probably the product of erosion of noritic rocks.
The regolith measured by the Chang’e-4 rover was actually a mixture of multiple sources, with ejections from the Finsen crater being primary and possible contributions from the Alder crater. The Finsen and Alder craters are on the fringes of the proposed impact fusion group produced by the SPA basin formation event. Therefore, the provenance of the regolith could originate from a differentiated fusion group or a set of igneous rocks.
Scientists conduct topographic analysis and mineral recovery based on Chang’e-4 data
Sheng Gou et al., Impact melt gap and surrounding regolith as measured by the Chang’e-4 rover, Letters of Earth and Planetary Science (2020). DOI: 10.1016 / j.epsl.2020.116378
Provided by the Chinese Academy of Sciences
Citation: Study reveals the composition of the ‘gel-like’ substance discovered by the Chang’e-4 rover on the far side of the Moon (2020, July 21) recovered on July 21, 2020 from https: // phys.org/news/2020-07-reveals- composition-gel-as-substance-change-.html
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