Lunar Mystery Revealed: The Moon's Age Now Known


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We now have a better idea of how and when the moon formed after an international team of planetary scientists revealed their findings in a recent study.

This is the closest we've come to a birth date for the moon which occurred within 100 million years of the birth of the solar system. The scientists established a "geological clock" that pins down when the moon formed and have published their study in Nature, titled - Origin of the Moon in a giant impact near the end of the Earth's formation.

The group of researchers came from France, Germany and the United States and by using measurements from the Earth's interior and in computer simulating the protoplanetary disk, they determined how the Earth and other planets in our solar system formed.

In analyzing the growth of Mercury, Venus, Earth and Mars from a disk displaying planetary building blocks orbiting the sun, and doing 259 simulations, they found the relationship between the time Earth was impacted by a very large object, to when the moon was created, including the amount of material added after impact.

The "geological clock" gave them the information that determined the early solar system history without requiring measurements or radioactive decay.

The authors wrote: "According to the generally accepted scenario, the last giant impact on Earth formed the Moon and initiated the final phase of core formation by melting Earth's mantle. A key goal of geochemistry is to date this event, but different ages have been proposed."

Adding, "some argue for an early Moon-forming event, approximately 30 million years (Myr) after the condensation of the first solids in the Solar System, whereas others claim a date later than 50 Myr (and possibly as late as around 100 Myr) after condensation. Here we show that a Moon-forming event at 40 Myr after condensation, or earlier, is ruled out at a 99.9% confidence level."

Lead author Seth Jacobson, from the Observatory de la Cote d'Azur in Nice, France, said: "We were excited to find a 'clock' for the formation time of the Moon that didn't rely on radiometric dating methods. This correlation just jumped out of the simulations and held in each set of old simulations we looked at."

Through their findings, the researchers determined that the moon is around 4.47 billion years old.

This clock will help the team use radioactive dating methods to make a closer estimate of the other planets and their ages.

Kevin Walksh
, from the Southwest Research Institute Space Science and Engineering Division, said: "This result is exciting because in the same simulations that can successfully form Mars in only two to five million years, we can also form the Moon at 100 million years. These vastly different timescales have been very hard to capture in simulations."

There was never a dispute as to how the moon formed, however, the timeline was in question.

Image via YouTube