Rock collected by US astronaut in 1972 reveals moon’s age
- Crystals suggest the moon is 40 million years older than scientists thought
- Sample used in study was brought back by Apollo 17 astronauts in 1972
During the Apollo 17 mission in 1972 – the last time people walked on the moon -US astronauts Harrison Schmitt and Eugene Cernan collected about 110.4kg (243 pounds) 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.
The leading hypothesis for lunar formation is that during the solar system’s chaotic early history a Mars-sized object called Theia slammed into primordial Earth.
This blasted magma – molten rock – into space, forming a debris disk that orbited Earth and coalesced into the moon. But the exact timing of the moon’s formation has been hard to nail down.
