The moon might be about 60 million years older than we thought, according to new research, which hones in on slightly less new research suggesting that the moon is about 100 million years younger than we thought. Confused?
Until recently, scientists had believed that the moon was formed after a Mars-sized object hit the Earth about 4.56 billion years ago. Back in September, however, scientists suggested that the moon is actually about 100 million years younger than we thought, because it was born 100 million years after our solar system formed. The Carnegie Institution for Science explained at the time that "geochemical data, improved simulations, and spacecraft exploration are challenging to the widespread acceptance of the currently favored giant impact hypothesis." Scientists concluded from analysis of lunar rocks that the moon may have formed about 4.4 billion or 4.45 billion years ago, explaining the new birthdate.
Now, however, scientists looking at Earth-bound crystals have come to a – slightly different conclusion. Science Daily reports:
Work presented today at the Goldschmidt Geochemistry Conference in Sacramento, California shows that the timing of the giant impact between Earth's ancestor and a planet-sized body occurred around 40 million years after the start of solar system formation. This means that the final stage of Earth's formation is around 60 million years older than previously thought.
The new research reflects analysis done on Earth-bound crystals, which uses ancient gas trapped inside the crystals to estimate when the Earth was born. Researcher Guillaume Avice said that "the gas sealed in these quartz samples has been handed down to us in a sort of 'time capsule.' We are using standard methods to compute the age of the Earth, but having access to these ancient samples gives us new data, and allows us to refine the measurement."
So the moon is younger than we thought it was, but not as much younger than we thought it was. At least, we think.