Washington: A new results from NASA’s Lunar Reconnaissance Orbiter (LRO) spacecraft found that Earth’s gravity has influenced the orientation of thousands of faults that form in the lunar surface as the moon shrinks.
In August, 2010, researchers using images from LRO’s Narrow Angle Camera (NAC) reported the discovery of 14 cliffs known as “lobate scarps” on the moon’s surface, in addition to about 70 previously known from the limited high-resolution Apollo Panoramic Camera photographs.
Due largely to their random distribution across the surface, the science team concluded that the moon is shrinking.
These small faults are typically less than 6.2 miles (10 kilometers) long and only tens of yards or meters high. They are most likely formed by global contraction resulting from cooling of the moon’s still hot interior. As the interior cools and portions of the liquid outer core solidify, the volume decreases; thus the moon shrinks and the solid crust buckles.
An analysis of the orientations of these small scarps yielded a surprising result: the faults created as the moon shrinks are being influenced by an unexpected source – gravitational tidal forces from Earth.
Lead author Thomas Watters said that there is a pattern in the orientations of the thousands of faults and it suggests something else is influencing their formation, something that’s also acting on a global scale, ‘massaging’ and realigning them.
Launched on June 18, 2009, LRO has collected a treasure trove of data with its seven powerful instruments, making an invaluable contribution to our knowledge about the moon.