India’s space agency, ISRO, has achieved a monumental first in space exploration, with its Chandrayaan-2 orbiter making an unprecedented observation. For the first time in history, a space agency has successfully captured the direct impact of a Coronal Mass Ejection (CME) from the Sun on the Moon’s exosphere. This groundbreaking discovery, made by the CHACE-2 instrument aboard Chandrayaan-2, offers invaluable insights into the Sun-Moon interaction.
Coronal Mass Ejections are colossal eruptions from the Sun’s outer atmosphere, the corona, releasing vast amounts of plasma and magnetic fields into space. These powerful events can significantly affect celestial bodies. On May 10, 2024, a series of CMEs struck the Moon, causing a dramatic surge in the pressure of its day-side exosphere. ISRO scientists reported a more than tenfold increase in the density of neutral atoms and molecules within this tenuous lunar atmosphere, validating long-standing theoretical predictions.
The Moon’s exosphere, being a ‘surface-boundary exosphere,’ is highly susceptible to solar activity due to the Moon’s lack of a global magnetic field. This CME event amplified the liberation of atoms from the lunar surface, temporarily altering its atmospheric conditions, all of which were meticulously recorded by Chandrayaan-2. These findings are crucial for understanding lunar space weather and will significantly influence the design of future lunar missions and potential human habitats on the Moon. The study detailing this historic observation was published in Geophysical Research Letters, solidifying India’s growing prominence in the global space arena.