Turning Back The Clock: The Moon Is 100 Million Years Younger Than Previously Believed

The moon is apparently much younger than previously thought. Based on new research, the moon is approximately 4.4 billion to 4.45 billion years old, 100 million years younger than previous estimates, which had Earth's satellite around 4.56 billion years old.

Richard Carlson, from the Carnegie Institute of Science, presented the research at the "Origin of the Moon" event at the Royal Society, reports Space.com. Carlson's age for the moon is based on new methods to date the rock from the lunar crust. Carlson's presentation, "Age of the Lunar Crust: Implications for the Time of Moon Formation," revises the moon's date after discovering rocks from Earth that date back to around 4.45 billion years ago, notes io9, that indicated a major impact event. According to Space.com, the moon is believed to have been formed from debris, ejected from Earth, after a planet, roughly the size of Mars, crashed into Earth early on in our solar system's history. The impact caused part of the rocky outer layer of the Earth to melt, and the molten rock would later reform, and researchers can analyze minerals from these rocks to determine their age.

Carlson analyzed levels of zircon in Earth rock from Western Australia, reports io9. Zircon is an extremely durable mineral, and scientists can look at its outer rings to learn more about geological events that happened early in Earth's history, reports the American Museum of Natural History. The rocks found on Earth indicate a "major differentiation event," the change in composition of the rock as a result of the planet being partially melted, around the same time as the hypothetical impact that created the moon, reports io9.

With these recent discoveries, as well as better methods to determine the age of lunar rock, scientists can create more accurate estimates of the moon's, as well as the Earth's age. It's much harder to calculate the age of a planet than an asteroid, and these new techniques could lead to a more accurate age of Earth and the moon. Carlson's recalculation could lead to new questions about the early history of the Earth, including the possibility that Earth's early atmosphere was destroyed by the impact that led to the formation of the moon.