Privileged Planet: making the moon (Introduction)

by David Turell , Monday, July 13, 2020, 22:52 (1598 days ago) @ David Turell

When Earth was very young, a smaller planet collided with it and knocked off what became the one moon we have and need:

https://phys.org/news/2020-07-younger-age-earth-moon.html

"The moon formed a little later than previously assumed. When a Mars-sized protoplanet was destroyed in a collision with the young Earth, a new body was created from the debris ejected during this collision, which became the moon. Planetary geophysicists at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), led by Maxime Maurice, together with researchers at the University of Münster, have used a new numerical model to reconstruct the time at which the event occurred—4.425 billion years ago. The previous assumptions about the formation of the moon were based on an age of 4.51 billion years—that, is 85 million years earlier than the new calculations reveal. The scientists have reported their findings in Science Advances.

"Four and a half billion years ago, the solar system was still chaotic. Earth was still growing to its present size, collecting matter in the form of what are referred to as planetesimals. These had previously formed in the disc of dust and gas orbiting the early sun. The young Earth consolidated, becoming ever hotter inside. Increasingly, large parts of the rocky mantle melted and formed a magma ocean. It is at this time that Earth gained the natural satellite that continues to orbit around it to this day. A massive cosmic collision between Earth and a protoplanet ejected rock from the young Earth. Eventually, this debris agglomerated to form a new planetary body—the moon.

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"It was not only Earth that had an ocean of magma in its early youth. Energy gained from accretion also led to the formation of a magma ocean on the moon. The moon melted almost completely and, similarly to Earth, was covered by a magma ocean over 1000 kilometers deep. This magma ocean quickly began to solidify and formed a crust of floating, lightweight crystals at the surface—its 'interface' with the cold space. But under this insulating crust, which slowed down the further cooling and solidification of the magma ocean, the moon remained molten for a long time. Until now, scientists were unable to determine how long it took for the magma ocean to crystallize completely, which is why they could not conclude when the moon originally formed.

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"This finding is significant because it allowed the authors to link the formation of different types of rock on the moon to a certain stage in the evolution of its magma ocean. "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," explains Sabrina Schwinger.

"The results of the study show that the moon was formed 4.425 ± 0.025 billion years ago. The moon's exact age is in remarkable agreement with an age previously determined for the formation of Earth's metallic core with the uranium-lead method, the point at which the formation of planet Earth was completed. "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," says Thorsten Kleine from the Institute of Planetology at the University of Münster."

Comment: Many entries in the past have described how important the moon is to have life on Earth. Not hard to realize this, like Chixculub, demonstrates the hand of God in action.