A groundbreaking study published in Nature has changed our perceptions of the moon’s origins: it may be older than 100 million years, according to a recent analysis. Previously, it had been estimated that the moon was born 4.35 billion years ago. It was an estimate from NASA’s Apollo missions by collecting lunar rock samples. New findings propose that the moon formed 4.51 billion years ago, overthrowing long-held beliefs.
The research, led by UC Santa Cruz professor Francis Nimmo, focuses on a dramatic event known as “re-melting,” which occurred while the moon was moving away from Earth. The heating produced by Earth’s gravity forces was so intense through tidal heating that it drastically altered the lunar surface and prevented scientists from knowing the actual age of the moon. “It reset the clocks in the lunar rocks that made them look younger,” said Nimmo.
The research is in line with increasing consensus among planetary scientists who have questioned how a major collision could have formed the moon 4.35 billion years ago. At that time, most large celestial bodies in the solar system had already formed. The older timeline also resolves discrepancies related to lunar zircon minerals, which are dated at 4.5 billion years but were puzzlingly older than the previous moon-formation estimate.
Tidal heating is the supposed mechanism for this phenomenon; it occurs when Earth’s gravitational pull stretches and compresses the moon’s surface, generating intense heat. Such processes are also observed in Jupiter’s moons, such as Io, where gravitational forces produce magma.
Carsten Münker, a geologist from the University of Cologne not involved in the study, described the findings as “exciting” and bringing the scientific community closer to a consensus on the moon’s age. He emphasized that knowing about the moon’s formation is critically important for understanding how rapidly the solar system evolved.
Current missions, for instance, China’s Chang’e 6 and NASA’s Artemis program, are aimed at possibly better understanding the lunar history, thus presenting us with new insights into the chaotic early days of our solar system.
