It's not such a huge change in the cosmic scheme of things, but researchers say the moon is millions of years younger than we thought. Specifically, a new model laid out in Science Advances pegs its creation at 4.425 billion years ago instead of the generally accepted figure of 4.51 billion years, per Phys.org. That would make the the moon 85 million years younger than thought. The model sticks with the theory that the moon formed when a rock the size of Mars collided with Earth, and the resulting debris congealed into our familiar satellite.
"The results of our latest modeling suggest that the young Earth was hit by a protoplanet some 140 million years after the birth of the solar system 4.567 billion years ago," says Maxime Maurice of the German Aerospace Center. "According to our calculations, this happened 4.425 billion years ago—with an uncertainty of 25 million years—and the moon was born." A post at Futurism notes that this means the moon formed at roughly the same time as the Earth's core. The team arrived at the conclusion by modeling how the composition of moon rocks changed as its giant magma ocean cooled and solidified. (Read more moon stories.)