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The Chandrayaan-2, during its lunar orbit, made a rare observation of the impact of the Sun’s Coronal Mass Ejection (CME) on the moon’s surface. This first-ever observation was captured by Chandra’s Atmospheric Composition Explorer-2 (CHACE-2).
Researchers from the Indian Space Research Organisation (ISRO) noted that the increased quantity of the Sun’s coronal mass emission had impacted the moon. It had knocked off the atoms from the lunar surface. Thus, liberating them to the lunar exosphere, which manifested as the enhancement of the total pressure in the sunlit lunar exosphere.
The moon has a very thin atmosphere called the exosphere. The gas atoms and molecules rarely interact despite their existence. The exosphere of the moon involves the interaction of the solar radiation, solar wind and the impact of meteorites with the moon’s surface. The exosphere is highly sensitive to small variations that are responsible for its creation, and one such is the CME.
The ISRO team also explained that the CMEs are events that occur when the Sun releases significant quantities of its building material, mostly comprising helium and hydrogen ions. These effects are significant on the moon, which has no magnetic field.
“On May 10, 2024, a series of CMEs were hurled from the Sun. The observations from CHACE-2 also showed an increase in the total pressure of the day-side lunar exosphere when the CME impacted the moon. The total number density also showed an increase by more than an order of magnitude,” the researchers noted. CHACE-2 onboard Chandrayaan-2 observed such an effect for the first time.
This observation will provide scientific insights into understanding the lunar exosphere and the space weather effects on the moon, the ISRO team noted and added that the episode also indicated the challenges of building scientific bases on the moon.
