Recent discoveries have shed light on the geological dynamism of the moon, particularly on its lesser-known far side. The near side of the moon is home to massive wrinkle ridges, extending from tens to hundreds of miles and towering hundreds of yards tall. In stark contrast, the far side exhibits significantly fewer maria—vast solidified lava plains formed billions of years ago—and thus, lacks extensive wrinkle ridges like those found on the near side.
The far side's wrinkle ridges tell a story of more recent activity. Formed in rare volcanic plains, these ridges are estimated to be between 84 million and 160 million years old. Unlike their near side counterparts, they measure about 328 feet (100 meters) in width and stretch approximately 3,280 feet (1,000 meters) in length. The existence of 266 such wrinkle ridges, clustered in groups of 10 to 40 within the far side maria, marks a relatively recent discovery.
The near side of the moon is characterized by the famous "Man in the Moon" pattern, created by large dark patches known as lunar maria. These areas, covering about 31% of the near side, are remnants of volcanic activity from 3.2 to 3.6 billion years ago. In comparison, only 1% of the far side is blanketed by these lava plains, due mainly to its thicker crust which hinders volcanic eruptions from reaching the surface.
The moon's ongoing contraction plays a pivotal role in its geological activity. As heat gradually leaks from its interior, the moon continues to shrink, potentially causing moonquakes detectable by seismometers. This contraction might also contribute to ongoing volcanic processes, suggesting that volcanism could still be occurring today.
Further evidence supporting recent lunar activity lies in volcanic glass beads found in lunar regolith, dated to approximately 123 million years ago. This discovery aligns with the formation of wrinkle ridges on the moon's far side, indicating a timeline for recent geological shifts.
Jaclyn Clark of the University of Maryland emphasizes the implications of these findings:
"Knowing that the moon is still geologically dynamic has very real implications for where we’re going to put our astronauts, equipment and infrastructure on the moon," – Jaclyn Clark of the University of Maryland
This insight into the moon's active geology challenges previous scientific consensus:
"Many scientists believe that most of the moon's geological movements happened two-and-a-half, maybe three billion years ago," – Jaclyn Clark
The newfound understanding that the moon remains geologically active necessitates a reevaluation of lunar exploration strategies. Planning for future missions must consider these dynamic conditions when selecting sites for human activities and equipment deployment.
