Analysis of lunar rocks collected during the Apollo missions has revealed new insights into the Moon’s mysterious magnetic field, scientists announced Wednesday. The findings suggest the Moon’s magnetic field was surprisingly strong – even exceeding Earth’s – during brief periods billions of years ago. Future samples gathered by NASA’s Artemis program are expected to provide even more detailed evidence.
The research, conducted by scientists at the University of Oxford in England and published Thursday in Nature Geoscience, challenges previous assumptions about the Moon’s magnetic history. Magnetic fields are crucial for shielding planets from harmful cosmic radiation and harsh solar radiation, as is the case on Earth.
According to lead researcher Claire Nichols, the Moon experienced “very short-lived spikes in magnetic field intensity,” lasting no more than 5,000 years – and potentially as little as a few decades. These spikes are believed to have been caused by the melting of titanium-rich rocks deep within the Moon.
Previously, scientists had assumed the lunar magnetic field remained strong for extended periods, based on analyses of rocks brought back by the Apollo missions between 1969 and 1972. This new understanding of intermittent magnetic activity could reshape our understanding of the Moon’s early evolution.
The Artemis program, set to send four astronauts on a crucial test flight around the Moon – potentially as early as April from Kennedy Space Center, following weeks of delays – will explore the Moon’s South Polar region. This differs from the Apollo missions, which focused on the low-latitude volcanic plains, and is expected to yield samples that further illuminate the Moon’s ancient magnetism.
Nichols and her team re-analyzed existing measurements from the Apollo samples, discovering that high levels of titanium correlated with evidence of past magnetic activity. The rocks collected during the first and last lunar landings, Apollo 11 and Apollo 17, were particularly rich in titanium. “We’ve found the missing link,” Nichols said in a statement. She added that the Moon’s magnetic activity may have been “strong intermittently, and perhaps more variable than we traditionally thought.”
Researchers believe the Apollo samples don’t accurately represent the Moon’s surface as a whole, as they were collected from similar, titanium-rich sites that were pushed to the surface by volcanic activity. The Artemis astronauts plan to study older rocks near the South Pole, where permanently shadowed craters are believed to contain water ice. Nichols emphasized that understanding the history of the Moon’s magnetic shield is “critical when thinking about the habitability of planets.”
