Scientists put age of moon at 4.51 billion years
Scientists have concluded that the moon is older than suspected - after studying rocks and soil collected in the 1971 Apollo landings.
A US research team reported on Wednesday that the moon formed within 60 million years of the birth of the solar system. Previous estimates ranged from 100 million years to 200 million years after the solar system's creation.
The scientists conducted uranium-lead dating on fragments of the mineral zircon extracted from Apollo 14 lunar samples.
The pieces of zircon were minuscule - no bigger than a grain of sand - but l ead study author Melanie Barboni, of the University of California in Los Angeles, said: "Size doesn't matter, they record amazing information nonetheless."
She noted that the moon holds "so much magic... the key to understand how our beautiful Earth formed and evolved".
Some of the eight zircon samples were used in a previous study, also conducted at UCLA.
Ms Barboni said she is studying more zircons from Apollo 14 samples, but does not expect the findings to change her estimate of 4.51 billion years for the moon's age - possibly extending it to 4.52 billion years at the most.
"It would be more a double-checking than anything else," she said of the research.
She and her colleagues - whose work appears in the journal Science Advances - are eager to learn more about the moon's history and, in turn, the evolution of early Earth and the entire solar system.
Apollo's Alan Shepard and Edgar Mitchell collected rocks and used tubes to dig up soil while exploring the moon's Fra Mauro highlands in February 1971.
They conducted two spacewalks, spending nine hours in total on the lunar surface.
It is the second major moon study detailed this week.
On Monday, Israeli scientists suggested Earth's constant companion may actually be a melting pot of many mini-moons.
Rather than one giant impact that shaved off a chunk of Earth and formed the moon, a series of smaller collisions may have created multiple moonlets that eventually merged into one, according to the researchers.
Ms Barboni said regardless of how the moon came to be - one big strike at Earth, many smaller ones, or even none at all - "you still end up at the end solidifying the moon as we know it today".
The giant impact theory claims the resulting energy formed a lunar lava ocean that later became solid. It is this solidification age that Ms Barboni and her team have now ascertained.
"We finally pinned down a minimum age for the moon formation," she said, "regardless of how it formed."