The moon, once thought to be a static, dormant celestial body, is now revealed to be a dynamic, ever-changing world. Recent scientific discoveries have unveiled a hidden truth: the moon is not only shrinking but also experiencing widespread tectonic activity, particularly in its dark basalt plains. This revelation challenges our understanding of the moon's geological history and has profound implications for future exploration and potential colonization.
The moon's surface is a patchwork of ancient volcanic plains, known as maria, which are now known to be riddled with fault ridges called small mare ridges (SMRs). These SMRs are not just random features but are part of a global network of tectonic activity, indicating that the moon is still slowly shrinking and wrinkling like a drying-out apple. The discovery of these SMRs, combined with the dating of the ridges, suggests that the moon's dark basalt plains are not as geologically quiet as previously believed.
The SMRs, which formed between approximately 310 and 50 million years ago, are the result of shallow thrust faults in the dark mare basalts. These faults trigger moonquakes strong enough to erase tiny impact craters nearby, providing a reliable timeline for the moon's contraction. The average age of the SMRs is around 124 million years, very close to the average age of the lobate scarps, which are another manifestation of the moon's gradual shrinkage.
The moon's contraction has left its mark on both the rocky highlands and the smooth, dark volcanic plains. This similarity suggests that the same global stresses are shaping both terrains, indicating that the moon's shrinkage is a global phenomenon. The widespread presence of recently or currently seismically active tectonic features across the maria provides new opportunities for future lunar missions and investigations, and highlights the potential hazards that shallow moonquakes pose to human-made lunar infrastructure.
The findings dramatically expand the inventory of possible seismic sources on the moon, broadening our toolkit for understanding the moon's ongoing evolution. The moon, once thought to be a static, dormant celestial body, is now revealed to be a dynamic, ever-changing world, with widespread tectonic activity and a shrinking surface. This new understanding of the moon's geology has profound implications for future exploration and potential colonization, and invites further discussion and research.
