A new study characterizes regular moonquakes
“Unlocking Lunar Secrets: Decoding Thermal Moonquakes and Beyond”
The Moon, with its stark lunar landscape, has always fascinated humanity. Recent research on lunar seismic activity has shed new light on an intriguing phenomenon — thermal moonquakes. These mysterious tremors on the lunar surface, tied to the Moon’s day-night cycle, have captivated scientists and space enthusiasts alike.
The Apollo 17 Mission and the Lunar Seismic Profiling Experiment (LSPE): During the Apollo 17 mission, a team of astronauts deployed geophones as part of the Lunar Seismic Profiling Experiment (LSPE). Their goal? To study the near-surface structure of the landing site by using explosive shots. Little did they know that this array would continue to unravel lunar secrets even after their mission’s completion.
The Lunar Temperature Rollercoaster: The Moon’s temperature experiences wild fluctuations due to its lack of atmosphere. It can soar to a scorching 250 degrees Fahrenheit during the day and plummet to a bone-chilling -208 degrees Fahrenheit at night. This extreme temperature shift causes the Moon’s surface to expand during the heat and contract during the cold, leading to thermal moonquakes — minor surface tremors and fractures.
Surprising Morning Tremors: Recent research has revealed a remarkable twist in the tale of lunar seismic activity. While thermal moonquakes are known to occur every afternoon as the Moon’s surface cools, a machine-learning algorithm identified unusual morning seismic events. These morning tremors turned out to be originating from the Apollo 17 lunar landing base, a few hundred meters away. The seismic array picked up the vibrations as the lander warmed and expanded in the morning.
Allen Husker’s Insight: Allen Husker, a research professor of geophysics and co-author of the study, explains, “Every lunar morning when the Sun hits the lander, it starts popping off, every five to six minutes another one, over a period of five to seven Earth hours. They were incredibly regular and repeating.”
Implications for Future Lunar Missions: While thermal moonquakes are too subtle for astronauts to feel, this research provides vital insights into the Moon’s thermal expansion and contraction. It’s crucial information for planning future lunar landers and their equipment. Husker adds, “Certain regions in the Moon’s South Pole craters never see sunlight; they are permanently shadowed. If we could put up a few seismometers there, we could look for water ice that may be trapped in the subsurface; seismic waves travel slower through the water.”
Conclusion: The Moon continues to surprise us with its hidden secrets, and the study of thermal moonquakes is just the beginning. As we explore further, we uncover not only the mysteries of our celestial neighbor but also valuable insights for future lunar missions. Stay tuned for more discoveries that will shape our understanding of the lunar frontier.
