Credit: Sarah Stewart/UC Davis based on NASA rendering
Earth’s moon formed inside a cloud of molten rock, and may have done so before our planet itself formed, a new theory suggests.
Scientists call such a cloud a synestia, a doughnut-shaped ring of debris full of molten rock that forms in the aftermath of a protoplanet collision. In this case, it would have been a massive collision early in our solar system’s history. According to the new theory, the moon formed within a few dozen years after the crash, as the synestia shrank and cooled. The Earth subsequently emerged about 1,000 years after the moon.















