Moon is older than we thought, suggests samples brought by Apollo 17 astronauts

For a new study published in the journal Geochemical Perspectives Letters, scientists used crystals brought back from the Moon by Apollo 17 astronauts in 1972 to better understand the timing of the Moon’s formation. Based on their discovery, the Moon is 40 million years older than previously thought, at least 4.46 billion years old, according to the University of Chicago.

The samples that the researchers used were brought back by astronauts during the last crewed mission to the moon. According to the researchers, these samples contain tiny crystals that formed billions of years ago, which could give signs about when the Moon was formed. When Earth was impacted by the Mars-sized object, the energy melted rock that eventually became the surface of the Moon.

“When the surface was molten like that, zircon crystals couldn’t form and survive. So any crystals on the moon’s surface must have formed after this lunar magma ocean cooled. Otherwise, they would have been melted, and their chemical signatures would be erased,” said Phillipp Heck, lead author of the study, in a press statement. Heck is a professor at the University of Chicago.

Since these crystals could have only formed after the “magma ocean” formed, their age would also tell us about the minimum possible age of the Moon. The scientists used an analytical method called atom probe tomography, which helped them arrive at the age of these crystals.

Learning more about the Moon will also help us understand a lot more about our own planet. The Moon stabilised the Earth’s axis and is part of the reason why a day goes on for 24 hours. It stabilised Earth’s rotational axis.