The Moon might be older than previously thought
A recent study published in the journal Nature offers a new explanation for the Moon’s age and its geological history, Kazinform News Agency correspondent reports.
The Moon is believed to have formed after a giant collision between the Early Earth and a Mars-sized protoplanet. Following this event, the Moon was covered in a vast ocean of magma that gradually cooled and solidified. Analysis of lunar rocks brought back by the Apollo missions indicates an age of about 4.35 billion years. However, the age of certain zircon minerals found on the Moon’s surface suggests the Moon could be as old as 4.51 billion years.
Scientists from the University of California, Santa Cruz, the Max Planck Institute, and Collège de France have proposed the hypothesis that around 4.35 billion years ago, the Moon underwent a global melting of its crust due to tidal forces from Earth. They suggest that, at some point in its early history, the Moon was much closer to Earth than it is today. This proximity caused strong tidal forces that generated internal friction and heating.
Such tidal heating could have been so intense that it triggered a global remelting of the Moon’s crust, similar to the volcanic processes seen today on Io, one of Jupiter’s moons, which is the most volcanically active body in the Solar System.
The global remelting could have erased traces of earlier geological events, effectively "resetting" the age of lunar rocks to the time of this event. This might also explain the small number of early impact craters on the Moon: their traces could have been destroyed during the crust's remelting. As a result, the Moon’s true age is likely in the range of 4.43 to 4.53 billion years.
To confirm this hypothesis, more complex models and additional lunar rock samples are needed. Future missions, such as China's Chang’e-6, which plans to return samples from the far side of the Moon, are expected to provide new data to better understand the processes that shaped the Moon’s history.
