A recent study published in Nature suggests that the Moon may be up to 100 million years older than estimated based on rocks collected from its surface. The findings show that the Moon’s surface underwent a “remelting” process 4.35 billion years ago, resetting the apparent age of the lunar rocks. This research aligns with simulations of planetary formation, which show that massive collisions capable of forming the Moon are likely to have occurred much earlier, within the first 200 million years of the Solar System’s formation.
Remelting theory provides new insights
According to Francis Nimmo, a planetary scientist at the University of California Santa Cruz who spoke to Space.com, tidal forces exerted by Earth on the early Moon may have caused widespread upwelling and intense heating. This process may explain why Moon rocks appear younger than the Moon’s actual age. Such melting events, similar to the activity seen on Jupiter’s moon Io, would have reshaped the lunar surface and erased early impact basins.
Help from rare lunar minerals
Rare lunar zircon minerals indicate that the Moon formed about 4.5 billion years ago, shortly after the Solar System began. This timeline matches dynamical models of the early Solar System, which suggest the accumulation of the most massive bodies 4.4 billion years ago. However, analysis of Apollo-era lunar samples previously suggested a lower age of about 4.35 billion years.
China’s Chang’e 6 mission may test findings
The study’s predictions could be verified with lunar samples to be obtained by China’s upcoming Chang’e 6 mission, which is scheduled to explore the far side of the Moon. Nimmo said additional lunar samples will be invaluable to refining these findings. Future simulations are planned to assess the specific effects of tidal heating on lunar geology.
The research highlights the interconnectedness of planetary science, providing a bridge between competing hypotheses from geochemistry and orbital dynamics.
