Moon is 85 million years younger than previously thought

The moon is slightly younger than planetary scientists previously assumed. A new study from the German Aerospace Center and the University of Münster has calculated a new age for Earth’s natural satellite: 4.425 billion years old or about 85 million years younger than was first thought.

The moon was first created when a Mars-sized protoplanet--commonly known as Theia--collided with Earth in the early days of its planethood. Molten material shot into space and consolidated to form the early iterations of the moon.

“From this, the Moon was formed in a short time, probably in just a few thousand years,” Doris Breuer, a co-author of the study and the Head of the Planetary Physics Department at the DLR Institute of Planetary Research, stated.

Like Earth, as the moon gradually grew in mass, an impressive magma ocean more than 1 thousand kilometers deep surrounded it. Scientists previously thought the magma took only 35 million years to completely solidify. The new study found the ocean was molten rock far longer.

The study used new mathematical models to track the moon's composition over time. It took comprehensive calculations regarding the crystallization of the magma ocean and the current age of moon rocks.

“The results from the model show that the Moon’s magma ocean was long-lived and took almost 200 million years to completely solidify into mantle rock,” Maxime Maurice, the leader of the team, stated. Maurice’s PhD thesis was the basis of this study.

The study is the first to directly link the formation of the moon with the formation of the Earth’s core, creating a more intertwined narrative between the planet and its' closest planetary neighbor.