# Buried Lunar Volcano Hints at Moon's Ancient Earth-Like Magnetic Field New research suggests the moon once had a geodynamo-driven magnetic field similar to Earth's. - **Source:** [All Articles | Discover Magazine](https://www.discovermagazine.com/rss/all) - **Published:** 2026-09-28 - **Original article:** - **On Brifing:** https://brifing.si/s/713ea435-878b-4c95-8c27-3d638cd7fd3e ## Apollo mission samples reveal mysteries Astronauts brought back 800 pounds of lunar material during Apollo missions, providing unprecedented data about the moon. These samples first revealed evidence of a past magnetic field, challenging previous assumptions about the moon's history. The nature and origin of this magnetism has remained a scientific debate for decades, with competing theories about its formation mechanisms. ## Dewar swirl's magnetic anomaly Researchers focused on the Dewar swirl, one of the moon's strongest magnetic anomalies located on its far side. This bright surface feature coincides with both magnetic and gravity anomalies, making it ideal for study. The team used these combined anomalies to calculate subsurface density and composition, revealing unique insights about the moon's internal structure beneath this region. ## Massive buried volcanic complex Analysis indicates the swirl sits atop a 37-mile-wide, 6-mile-deep buried volcanic structure formed 4.2 billion years ago. This solidified magma body contains iron-bearing minerals that became magnetized as they cooled. Based on the iron content, researchers calculated the ancient magnetic field strength to be at least 11.4 microteslas, comparable to Earth's current surface field strength. ## Geodynamo theory supported The findings support the theory that the moon's field was generated by geodynamic forces like Earth's, rather than impact events. The field likely originated from motion in a molten metallic core, though questions remain about how such a strong field formed in the moon's relatively small core. This challenges existing models of planetary dynamo formation and scaling. ## New perspective on lunar history The research shifts the scientific question from whether the moon had a dynamo to understanding how it worked. It supports emerging evidence that the moon experienced intense but possibly intermittent magnetic periods early in its history. These findings align with other recent studies suggesting short, powerful magnetic events lasting less than 5,000 years. ## Implications for planetary science Understanding the moon's magnetic history provides insights into planetary formation processes across the solar system. The presence of an Earth-like dynamo suggests the moon's early thermal and chemical evolution was more complex than previously thought. This has implications for modeling magnetic field generation in other rocky bodies throughout the universe. ## Future mission priorities The study highlights the Dewar region as a key target for future lunar exploration missions like Artemis and Chang'e. Researchers emphasize the need for additional magnetic and geological data to resolve remaining questions about the moon's thermal evolution. These findings demonstrate how much we still have to learn about Earth's closest celestial neighbor. ## Scientific methodology advances The research demonstrates innovative use of combined gravity and magnetic data analysis for planetary science. This approach could be applied to study other celestial bodies where direct sampling isn't possible. The team's methods provide a template for extracting maximum information from limited extraterrestrial geological data. ## Sources covering this story - https://www.discovermagazine.com/hidden-lunar-volcano-suggests-the-moon-once-had-an-earth-like-magnetic-field-49736 — --- _Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._