How was this known? Thanks to a group of scientists. He analyzed evidence of zircon crystals from lunar soil. They are the oldest particles on the satellite. The results prove it. The moon is older than thought.
The Moon is supposed to have formed shortly after the Earth, about 4.4 billion years ago. It is believed that an object the size of Mars collided with the Earth, which was still hot, soft and newly formed. It released a huge cloud of debris that orbited the Earth and became the Moon.
Apollo 17 Mission
A new one says it is older by about 40 million years than we thought. This means that the Moon has a minimum age of 4.46 billion years. The team led by geologist Jennika Greer, from the University of Glasgow, believes so.
«These crystals are the oldest known solid elements formed after a large impact. We know how old these crystals are, so they serve as an anchor for the lunar chronology,” they point out. Zircon crystals are an excellent means of determining the age of a specimen. During the formation process, zircon crystals incorporate uranium. But they greatly dislike lead. Over time, the radioactive uranium in zircon decays into lead at a well-studied rate. From the ratio of uranium and lead in a zircon crystal, scientists know when it formed.
These microscopic crystals can be found in lunar soil samples recovered during the Apollo era. Greer and his colleagues studied zircon found in samples from the Apollo 17 lunar mission in 1972. They must have formed after the lunar surface solidified.
Point
The researchers used atomic probe tomography to study the composition of the samples. They used a laser to vaporize atoms. A mass spectrometer analyzed the gravity of the vaporized material. And they found the proportion of uranium and lead. In turn, this showed that the moon is older than thought. The specific crystals are 4.46 billion years old. This implies that the Moon must be at least that old.
«It is a starting point for many questions about the Earth. “When you know the age of an object, you can better understand what happened to it during its history,” Greer concludes.
