Scientists have revealed that the moon's true age is 40 million years older, pushing its formation back to 4.46 billion years ago. This is revealed in a paper published in the journal Geochemical Perspectives Letters, published by the European Association for Geochemistry.
Researchers analyzed zircon crystals in a sample of moon dust returned to Earth by Apollo astronauts in 1972. The Moon is thought to have formed from Earth's collision with a Mars-sized object, so these crystals must have formed after cooling the molten surface of the Moon. Determining the age of the zircon crystals allows us to estimate the minimum possible age of the Moon.
The scientists used a technique called atom probe tomography. First, the lunar sample is sharpened with a focused beam of ions, then ultraviolet lasers knock atoms from the surface of the sharp tip. The atoms pass through a mass spectrometer that determines their mass based on how fast they are moving, allowing scientists to determine the isotopic composition of uranium and lead atoms. When an atom has an unstable configuration of protons and neutrons in its nucleus, it undergoes decay, losing some of those protons and neutrons and becoming different elements. Since we know how long the half-lives of uranium isotopes take to form lead, the age of the crystals can be determined from the isotope ratio. The results show that the sample is about 4.46 billion years old. /BGNES
