Source: TOI
Context: A new NASA study using data from the GRAIL mission has revealed why the Moon’s nearside and farside look so different, solving a decades-old lunar mystery.
About GRAIL mission:
- What is GRAIL?
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- GRAIL (Gravity Recovery and Interior Laboratory) was a NASA lunar science mission aimed at mapping the Moon’s gravitational field in high resolution.
- Launch Year: Launched in 2011 using a Delta II rocket from Cape Canaveral.
- Organizations Involved: Conducted by NASA’s Jet Propulsion Laboratory (JPL) in collaboration with MIT for scientific oversight.
- Key Features:
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- Consisted of two spacecraft, named Ebb and Flow, flying in tandem around the Moon.
- Measured minute variations in gravitational pull to reveal the Moon’s internal composition.
- Ended with a controlled impact on the lunar surface after successful mission completion.
Key Discoveries from GRAIL:
- Tidal Deformation & Gravitational Asymmetry: The Moon’s nearside flexes more than the far side due to Earth’s gravitational pull, indicating asymmetry in internal structure.
- Volcanic History & Heat Distribution:
- The nearside was more volcanically active, with dark basaltic plains (“known as mare”).
- Higher concentrations of heat-producing elements like thorium and titanium warmed the nearside mantle up to 200°C more than the farside.
- Crustal Thickness Variation:
- Nearside crust is thinner, allowing magma to erupt more easily, forming flat plains.
- Far side remains rugged and cratered due to thicker crust and less volcanic activity.
