Apollo crystals reveal the moon’s true age

The Moon is Earth’s most reliable partner in space, orbiting our world for about 4.5 billion years, roughly the same length of time as our planet. But new analysis of crystals from the moon’s surface suggests the satellite may be older than previously thought.

The Moon is thought to have formed when the early Earth collided with a Mars-sized protoplanet, an event dated to about 4.35 billion years ago based on rocks on the Moon’s surface. Determining the timeline of the Moon’s evolution not only informs us about the history of this rocky domain, but helps planetary scientists understand the evolution of our universe and the larger solar system.

Now, a team of researchers hypothesizes that while estimates of the Moon’s age range between 4.35 billion and 4.51 billion years ago, the younger date indicates a remelting event different from “the original crystallization of the lunar magma ocean,” they wrote in their article. paper published Today in nature.

The sheer number of 4.35 billion-year-old rocks on the surface suggested to the team that they were due to a large-scale remelting event, and that the Moon’s true age was somewhat older. Researchers extracted older ages from zircon crystals from the moon’s surface, which were recovered by the Apollo missions. Although the rest of the Moon’s surface has undergone remelting, some near-surface crystals have not, and thus a more accurate record of the Moon’s age is kept.

The team points out that it is almost certain that the Moon is no more than 4.53 billion years old, which is “the earliest time at which core formation could have stopped.” The earliest possible time for the moon to form is about 180 million years before a subsequent tidal heating event on the satellite, the researchers said. In other words, if the Moon’s surface we know and love is largely the result of a remelting event, and the Moon is older than generally thought, then it’s not. Superbly Older than thought.

“Current models do not support the idea of ​​collisions being responsible for the reset event,” the team stated in their paper, although the jury is still out on what might have caused the widespread melting of the lunar surface. The remelting process may have been “driven by the Moon’s orbital evolution” — in other words, gravitational pressure on the Moon by objects like the Earth and the Sun, the researchers said.

Earlier this year, research published in Natural Earth Sciences He concluded that the Moon likely turned itself upside down a few million years after its formation. The new paper further complicates the origin story of our ancient solar orbit partner.

We still have it Long way to go With space exploration, though Artemis program– which will return humanity to the moon for the first time in decades – will be an important step in understanding the origins of our rocky satellite.