(CN) — Scientists knew the moon was old based on decades of scientific testing and even older models, but exactly how old remained a subject for heated debate. A study published Monday in the academic journal Geochemical Perspectives Letters revealed scientists — using more advanced dating technology — have determined the moon is at least 40 million years older than previously thought.
Using atom probe tomography, an analytical method that allows scientists to study the microstructure of things at the atomic level, researchers got a closer look at lunar dust from the moon brought to Earth by astronauts on board the Apollo 17 in 1972 — the last time humans set foot on the moon.
The moon dust contains tiny crystals made up of a mineral called zircon, which are the oldest known solid materials that formed after a Mars-sized planet collided into Earth and created the moon in what scientists refer to as the giant-impact hypothesis.
The energy of the impact melted rock and created a lunar magma ocean, which eventually cooled and became the moon’s surface, so the zircon crystals from the dust brought back by astronauts should give us the minimum possible age of the moon.
Based on previous studies and models, scientists thought the moon was somewhere between 4.42 and 4.52 billion years old, but the study authors determined that the crystals were 4.46 billion years old, meaning the moon itself must be at least that old.
Philipp Heck, the senior director of the Negaunee Interactive Research Center, a professor at the University of Chicago and the study’s senior author, said that the study not only gives us an anchor to the history and chronology of the Moon, but it gives us insight into Earth’s timeline and development.
“We think the moon formed in common together with the earth with the same giant impact,” Heck said. “Only after that impact did the earth become habitable”
The moon stabilized Earth’s rotational axis, Heck said, making the development of life on Earth more stable. The moon is also responsible for our 24-hour days and our tides. By studying the moon and its history, we can deepen our understanding of how Earth formed, how life started here, and why we’re here, Heck said.
“To better understand the origins of Earth, ironically, we have to go and study the moon,” he added.
Heck said he wants to try to find older samples of zircon crystals, since there is a possibility that there are older samples on the moon. He would also like to get samples from the surface of Mars, which could provide some answers to the question if there was once life on Mars.
Missions to space might seem expensive, he said, but a lot of knowledge can be gained from samples of minerals on other planets by a wide variety of scientists in a lot of different disciplines.
“It’s a small price to pay,” Heck said.
There’s also a possibility that new and improved technology in the future could prove that the zircon crystals are even older than the atom probe tomography showed, Heck added.
“Fifty years from now, there will be new techniques. We don’t even know what they’ll be.” he said, and the scientists in the future will be able to find answers to things their forebearers didn’t even think to ask.
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