A revolutionary new study reveals that the Moon may be older than previously believed, despite its youthful appearance. Research published in Nature suggests that intense volcanic activity around 4.35 billion years ago essentially reset the Moon’s geological clock, shedding light on its ancient origins and solving a long-standing mystery about its age.
Published in Nature | Estimated reading time: 6 minutes
Scientists have long been puzzled by the age of the Moon, with estimates varying by millions of years. While most lunar rocks indicate an age of around 4.35 billion years, rare zircon crystals suggest a much older origin. The recent study explains this discrepancy by pointing to a period of intense volcanic activity that essentially transformed the Moon’s geological makeup.
According to lead author Francis Nimmo from the University of California Santa Cruz, the key lies in understanding the Moon’s early interactions with Earth. During a phase when the Moon was much closer to Earth, variations in its orbit led to significant internal heating, similar to what we observe on Jupiter’s moon Io today.
The research team, led by Professor Thorsten Kleine from the Max Planck Institute for Solar System Research, found that this internal heating caused most of the Moon’s crust to remelt. Kleine explains, “The intense volcanism likely reset the Moon’s geological clock, revealing only when the rocks were last heated, not their original age.”
This discovery helps explain many mysterious aspects of the Moon, such as its relatively smooth surface with fewer impact craters than expected for its age. Professor Alessandro Morbidelli from the Collège de France highlights how lava from the Moon’s interior likely filled ancient impact basins, making them unrecognizable.
The study places the Moon’s true age between 4.43 and 4.51 billion years old, with its youthful appearance stemming from a major remelting event around 4.35 billion years ago. This finding aligns with our understanding of the early solar system dynamics, where planetary bodies were forming through cosmic collisions.
Glossary
- Tidal Heating: A process where gravitational forces generate internal heat, causing significant geological changes.
- Zircons: Heat-resistant crystals preserving evidence of the Moon’s early history.
- Geological Clock: A dating method using radioactive isotopes to determine rock ages based on known decay rates.
Test Your Knowledge
What is the currently accepted age range for the Moon?
Between 4.43 and 4.51 billion years old.
How far was the Moon from Earth during its intense heating phase?
About one-third of today’s distance (around 384,400 kilometers).
Why do most lunar rock samples appear younger than the Moon’s actual age?
The volcanic activity around 4.35 billion years ago reset their geological clocks, revealing only their last heating event, not their original formation date.
How does tidal heating explain the Moon’s apparent age and surface features?
Tidal forces caused widespread remelting that reset the rocks’ clocks and filled in ancient impact basins, creating a smoother surface that appears younger than it is.
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