Overview

• The moon is 4.46 billion years old, approximately 40 million years older than previously believed, according to analysis of lunar rocks collected by Apollo 17 astronauts in 1972.
• Researchers used atom probe tomography to date lunar zircon crystals, which are the oldest known solids formed after a giant impact event led to the creation of the moon.
• Zircon crystals could not form and survive until after the lunar magma ocean cooled, so their age provides a minimum bound for the age of the moon.
• The process of atom probe tomography involves sharpening a lunar sample to a very fine point, then using UV lasers to evaporate atoms from the surface of the tip. The atoms are then analyzed for their weight and composition to determine their age.
• The age of the moon is significant to our understanding of Earth's history and its stabilizing effects on our planetary system, including the 24-hour day length and the presence of tides.