# Earth's Gravity May Have Sustained Ancient Lunar Volcanism Tidal heating likely kept the Moon's interior molten long after its formation. - **Source:** [Universe Today](https://www.universetoday.com) - **Published:** 2026-11-06 - **Topic:** [science](https://brifing.si/c/science) - **Original article:** - **On Brifing:** https://brifing.si/s/2f6d3f05-bbd4-4757-bee3-c53e277afdbf ## Challenging Static Lunar Models Traditional physics suggests the Moon should have become geologically dormant shortly after its formation 4.5 billion years ago. However, basalt samples returned by the Chang’e-5 mission indicate volcanic activity occurred as recently as two billion years ago. This discrepancy forces scientists to reconsider the thermal evolution of our nearest celestial neighbor. ## Limitations of Internal Heat Radioactive decay of elements like potassium and uranium cannot account for the heat required to produce these relatively young basalts. Furthermore, asteroid impacts were insufficient to generate the necessary thermal spikes during that era. Researchers needed a more robust mechanism to explain how the Moon maintained a molten interior for so long. ## The Role of Tidal Heating The study proposes that tidal heating, caused by gravitational interactions with Earth, provided the missing energy. Two billion years ago, the Moon orbited closer to Earth in a highly elliptical path. This rhythmic stretching and squeezing of the lunar interior generated significant heat, similar to the volcanic activity observed on Jupiter's moon Io. ## Modeling the Lunar Interior Previous models incorrectly assumed the Moon was a uniform sphere. The new research utilizes a 3D simulation incorporating an ultra-low viscosity zone between the core and mantle. This realistic representation reveals how gravitational forces focus energy into specific regions, rather than distributing it evenly across the entire lunar body during its orbit. ## Tidal Heating Anomaly Zones The team identified Tidal Heating Anomaly Zones (THAZs) at the core-mantle boundary. Despite occupying only 2.5% of the mantle's volume, these zones absorbed immense energy. Around 3.2 billion years ago, they generated 150 gigawatts of power, which is four times the energy produced by radioactive decay, effectively acting as a long-term thermal engine. ## Sustaining a Magnetic Field This internal heat likely kept the lunar core warm, sustaining a magnetic field for a much longer duration than previously predicted. This finding resolves a long-standing puzzle regarding Apollo samples, which appeared to have formed within a strong magnetic field. The tidal engine provided the necessary energy to drive this ancient lunar dynamo. ## Formation of Recent Basalts The tidal engine drove massive mantle plumes that swelled toward the crust. Long after these tidal forces subsided, stranded pockets of mantle remained molten. These pockets eventually produced the basalts identified in the Chang’e-5 samples, providing physical evidence of the Moon's complex geological history that persisted well beyond its initial cooling phase. ## Future Lunar Exploration Goals While this model offers an elegant solution to persistent questions, it remains a theoretical framework. Future lunar missions planned over the next decade are essential to provide definitive data. These upcoming explorations will test the validity of the THAZ model and further clarify the evolutionary timeline of the Moon's mysterious geological past. ## Sources covering this story - https://www.universetoday.com/articles/earths-gravity-may-have-kept-the-early-moons-volcanic-heart-beating — --- _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._