When we think of the Moon, the first thing that comes to mind is its pockmarked surface, marked by countless craters. However, a recent study conducted by astrophysicist Jianqing Feng and his team at the Planetary Science Institute in Arizona reveals a different kind of chaos hidden beneath the lunar surface: a succession of lava flows. Utilizing data from the Chang’e-4 rover, which landed on the far side of the Moon in 2019, Feng and his team delved deep into the lunar subsurface, uncovering intriguing findings.
Feng’s team took advantage of the vast amount of data collected by the Chang’e-4 rover, surpassing the limited data from previous studies. By utilizing lower frequencies of ground-penetrating radar, they were able to peer deeper into the lunar surface. The lunar penetrating radar instrument aboard the rover emits pulsing signals into the subsurface, allowing scientists to analyze the reflections and determine the composition and structure beneath.
As Feng and his colleagues analyzed the data, they discovered a series of basalt eruptions that occurred billions of years ago. Through their investigation, they identified multiple layers in the upper 300 meters, indicative of these ancient volcanic events. The layers of hardened lava, found deeper down, gradually thinned towards the surface, suggesting a decrease in eruption scale over time. The thickest layers measured approximately 70 meters wide, while the lava flows narrowed to around 5 meters near the landing site.
Unraveling the History of Lunar Volcanism
Lunar volcanism has recently become a fascinating field of study. Scientists have found unusual hotspots on the far side of the Moon, providing evidence of a unique type of volcanism. Furthermore, the retrieval of lunar rocks after four decades has led to the realization that lava flowed from Moon’s volcanoes for a billion years longer than previously believed. The hardened lava layers detected by Feng’s team serve as another testament to the Moon’s volcanic history, providing valuable insights into the changes that occurred over time.
A Record of Lunar Events
These lava flows are not merely isolated events but a record of the Moon’s turbulent volcanic history. Feng and his team believe they have identified at least three or four large lava flow events, with some occurring in close proximity to each other. These events are separated by thin layers of lunar soil, which solidified into rock between the lava flows. The researchers also cross-checked their measurements against data from a previous lunar module, Chang’e 3, confirming the presence of these subsurface features across the Von Kármán crater.
While their findings shed light on the nature of lunar volcanism, they do not provide information about the precise timing of these volcanic events. The remote-sensing data collected by the Chang’e-4 rover can only reveal the relative sizes of the lava flows, indicating a decrease in scale over time as the Moon’s internal thermal energy waned. Other recent studies have sought to refine our understanding of the Moon’s previous episodes of volcanic activity, but the timing remains elusive.
The Scrutiny and Debate Continues
As with any scientific discovery, Feng’s findings are subject to scrutiny and further investigation. Some scientists question the interpretation of the subsurface layers detected through low-frequency lunar penetrating radar, suggesting that they may be due to system noise. Therefore, these new results are likely to undergo rigorous examination in the scientific community.
The Moon continues to captivate scientists and researchers with its enigmatic features. Feng’s study provides valuable insights into the lunar subsurface, revealing a tumultuous volcanic past hidden beneath its crater-laden surface. By analyzing the data collected by the Chang’e-4 rover, Feng and his team unveiled a record of ancient basalt eruptions, offering a glimpse into the Moon’s distant past. As further studies unravel the mysteries of lunar volcanism, our understanding of Earth’s celestial neighbor will undoubtedly deepen.