How old is our Moon, and could its true age be different than previously hypothesized? This is what a recent study published in Nature hopes to address as an international team of researchers investigated specific geological processes on the Moon that could indicate the Moon’s true age is older than longstanding estimates, which range between 4.35 and 4.51 billion years old, depending on which types of lunar samples are examined. This study has the potential to help researchers better understand the formation and evolution of our Moon, which could help determine when life began on the Earth.
“We predict that there shouldn't be any lunar rocks that are older than 4.35 billion years because they should have experienced the same resetting,” said Dr. Francis Nimmo, who is a professor of Earth and planetary sciences at UC Santa Cruz and lead author of the study. “Because this heating event was global, you shouldn't find rocks anywhere on the Moon that are significantly older than that.”
For the study, the researchers suggest the Moon experienced what’s called a “remelting” event due to the tidal forces from the Earth, resulting in a geological “reset” that hid the Moon’s true age, indicating the Moon could be older than previously hypothesized. The researchers used a series of computer models to test their hypothesis and demonstrated this remelting took place approximately 4.35 billion years ago, along with ascertaining that the Moon was formed between 4.43 and 4.53 billion years ago. For context, the approximate age of the Earth is 4.54 billion years old, and the approximate age of the solar system is 4.6 billion years old.
Artist's rendition of the Moon during its alleged geological "reset" caused by tidal forces from the Earth. (Credit: Alexey Chizhik/Max Planck Institute for Solar System Research)
“As more data becomes available—particularly from ongoing and future lunar missions—the understanding of the Moon’s past will continue to evolve,” said Dr. Nimmo. “We hope that our findings will spark further discussion and exploration, ultimately leading to a clearer picture of the Moon’s place in the broader history of our solar system.”
This study comes as NASA gearing up its Artemis Program with the goal of landing the first astronauts on the lunar surface for the first time since Apollo 17 in 1972. These future astronauts could collect lunar samples and return them to Earth, thus providing scientists with opportunities to learn more about the Moon’s history and its true age.
What new discoveries about the Moon’s true age will researchers make in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!
Sources: Nature, EurekAlert!, UC Santa Cruz, NASA
