According to a new study, researchers from the German Aerospace Center discovered that our moon is 85 million years younger than previously thought. A Mars-size protoplanet collided with an infant Earth billions of years ago and the debris eventually came together to form our moon. While previous studies have indicated that this occurred 4.51 billion years ago, the new analysis states that our moon was born 4.425 billion years ago – 85 million years later.
First, let’s talk about other recent news that ties in with this current story. Just recently, scientists revealed that the moon’s magma ocean lasted for about 200 million years – much longer than previously thought. “An important outcome of this scenario is that the early moon, which accreted from the debris of this giant impact, was very hot — hot enough for its rocky mantle to be largely molten and form what we call a magma ocean,” Maxime Maurice, who is a planetary scientist at the German Aerospace Center in Berlin as well as the lead author of the study, explained to Space.com.
“While the idea of a primordial magma ocean on the moon is largely accepted, the time it took to solidify was not very clear,” Maurice said, adding, “Previous models suggested it was fairly rapid — some tens of millions of years.” However, according to their analysis, the moon’s magma ocean may have solidified over 150 million to 200 million years – ten times longer than previously believed.
Now, getting back to this current story on the moon’s age, researchers used mathematical models to calculate how long it took the magma to solidify and change throughout the years. Sabrina Schwinger, who is a researcher at the German Aerospace Center as well as a co-author of the study, explained this further, “By comparing the measured composition of the moon’s rocks with the predicted composition of the magma ocean from our model, we were able to trace the evolution of the ocean back to its starting point, the time at which the moon was formed.”
This new research also matches previous analysis that indicated that the formation of the moon coincided with the formation of Earth’s metallic core. This is certainly a significant and important discovery, as Thorsten Kleine, who is a professor at the Institute of Planetology at the University of Münster in Germany, stated, “This is the first time that the age of the moon can be directly linked to an event that occurred at the very end of the Earth’s formation, namely the formation of the core.”