The BRICS TimesThis pioneering Coronal Mass Ejection finding deepens our understanding of the fragile lunar atmosphere. It also sheds light on crucial space weather effects on the Moon.
Pioneering Observation by Chandrayaan-2
India’s Chandrayaan-2 lunar orbiter achieved a global first on Saturday. It directly observed the Sun’s Coronal Mass Ejection (CME) effects on the Moon. The onboard instrument Chandra’s Atmospheric Composition Explorer-2 (CHACE-2) recorded this.
CME’s Impact on Lunar Exosphere
CHACE-2 data revealed a surge in total pressure. This happened in the dayside lunar exosphere (fragile atmosphere) during the CME impact. Scientists noted an increase by more than an order of magnitude. This refers to the derived total number density. This density is the number of neutral atoms or molecules per unit volume. The official statement confirmed this finding. The increase aligns with earlier theoretical models. However, CHACE-2 on Chandrayaan-2 saw this effect directly for the first time.
Understanding the Moon’s Exosphere
The Earth’s Moon possesses a very fragile atmosphere. This is specifically known as an ‘exosphere’. Gas atoms and molecules rarely interact there despite coexisting. The lunar surface itself forms the exosphere’s boundary. Therefore, it is categorized as a ‘surface boundary exosphere’. The Moon’s exosphere forms through several processes. These involve solar radiation and solar wind interaction. The solar wind consists of Hydrogen and Helium ions. Meteorite impacts with the surface also contribute to this.
Solar Eruptions and Their Effects
These processes release atoms or molecules from the surface. They then become part of the exosphere. The Moon’s exosphere is extremely sensitive to minor changes. A key factor is the Sun’s coronal mass emission, called CME. CMEs are events where the Sun ejects huge amounts of its material. This material mainly includes Helium and Hydrogen ions. These effects are major because the Moon lacks air. It also has no global magnetic field. A magnetic field would have partially shielded the surface from solar effects.
Rare Opportunity and Future Challenges
This unique opportunity for observation occurred on May 10, 2024. The Sun hurled a series of CMEs towards the Moon. The enhanced solar coronal mass impacted the lunar surface. This intensified the process of knocking atoms off the surface. These liberated atoms entered the lunar exosphere. This change appeared as an increased total pressure. It happened in the sunlit lunar exosphere.
This key observation offers scientific insight. It helps to better understand the lunar exosphere and space weather. This pushes the limits of our scientific knowledge about the Moon. It also highlights challenges for building bases on the Moon. Lunar base architects must consider such extreme events. These events will temporarily change the lunar environment. They must account for this before the effects diminish.
