In a groundbreaking discovery, lunar dust collected by the Apollo 17 mission in the 1970s has revealed that the moon is 40 million years older than previously estimated. This revelation comes after a new analysis of zircon crystals found in the collected sample, which have been dated to be 4.46 billion years old. The findings not only provide insight into the moon's age, but also shed light on the early days of our solar system.

The Apollo 17 mission, led by NASA astronauts Eugene Cernan and Harrison Schmitt, landed on the moon on December 11, 1972. During their mission, they collected rocks and dust from the lunar surface, which have been valuable sources of information for scientists ever since. However, it was only recently that a detailed analysis of the zircon crystals within the lunar dust sample provided a more accurate age for the moon.

"These crystals are the oldest known solids that formed after the giant impact. And because we know how old these crystals are, they serve as an anchor for the lunar chronology," explained Philipp Heck, senior study author and Robert A. Pritzker Curator for Meteoritics and Polar Studies at the Field Museum of Natural History in Chicago.

The moon's formation is believed to have occurred over 4 billion years ago, when a Mars-sized object collided with Earth, causing the ejection of a large rocky piece that eventually became the moon. Determining the precise age of this event has been a challenge for scientists. However, the discovery of zircon crystals in the lunar dust provided an opportunity to unlock this mystery.

The study, led by senior author Jennika Greer, a research associate in Earth Sciences at the University of Glasgow, used an advanced technique called atom probe tomography to analyze the chemical composition of the zircon crystals. This technique allowed researchers to track the decay of uranium atoms to lead atoms, providing a means to determine the age of the crystals.

The results of the analysis revealed that the zircon crystals within the lunar dust sample were 4.46 billion years old, indicating that the moon must be at least that old. This new estimate pushes back the moon's age by 40 million years from previous estimations.

"It's amazing being able to have proof that the rock you're holding is the oldest bit of the Moon we've found so far," remarked Greer. "It's an anchor point for so many questions about the Earth. When you know how old something is, you can better understand what has happened to it in its history."

The significance of this discovery extends beyond the lunar samples themselves. Understanding the age of the moon provides insights into the early history of our solar system and the processes that shaped our planet. The technology used in this analysis has also highlighted the importance of preserving and studying pristine lunar samples, prompting NASA to continue unsealing and analyzing samples collected during the Apollo era.

"The Moon is an important partner in our planetary system," stressed Heck. "It stabilizes the Earth's rotational axis, it's the reason there are 24 hours in a day, it's the reason we have tides. Without the Moon, life on Earth would look different. It's a part of our natural system that we want to better understand, and our study provides a tiny puzzle piece in that whole picture."

The findings from the analysis of the Apollo 17 samples not only contribute to our knowledge of the moon's history but also underscore the magnitude of scientific discoveries that can be made even decades after a mission's completion. The increased understanding of the moon's age will undoubtedly lead to further investigations and advancements in our understanding of the solar system's formation.