During the Apollo 17 mission in 1972 - the last time people walked on the moon - U.S. astronauts Harrison Schmitt and Eugene Cernan collected about 243 pounds (110.4 kg) of soil and rock samples that were returned to Earth for further study.
A half century later, crystals of the mineral zircon inside a coarse-grained igneous rock fragment collected by Schmitt are giving scientists a deeper understanding about the moon's formation and the precise age of Earth's celestial partner.
The moon is about 40 million years older than previously thought - forming more than 4.46 billion years ago, within 110 million years after the solar system's birth, scientists said on Monday, based on analyses of the crystals.
