It is often said the Moon plays a crucial role for life on Earth, since the gravitational pull of our natural satellite helps to stabilize our planet. New research now suggests that this role started as soon as the Moon formed 4.5 billion years ago.
For the study, American researchers looked for an explanation for the more than five-degree tilt the Moon's orbit has with respect to Earth’s orbit around the Sun. This is very different compared to most of the satellites orbiting other planets, as they usually orbit close to the planet's equator and not the orbital plane.
Looking for an explanation, the scientists discovered that when the Moon formed, it might have caused our planet to almost orbit on its side. It was only later that the Moon was responsible for straightening it up.
“Evidence suggests a giant impact blasted off a huge amount of material that formed the Moon,” said co-author Douglas Hamilton, professor of astronomy at the University of Maryland, in a statement. “This material would have formed a ring of debris first, then the ring would have aggregated to form the Moon. But this scenario does not quite work if the Earth’s spin axis was tilted at the 23.5-degree angle we see today.”
The computer simulation suggests that the impact might have pushed the tilt of Earth to more than 70 degrees and made our planet spin really fast, with the disk of debris forming the Moon around its equator, 15 times closer to where it is today. The Moon was then tugged by both our planet and the Sun in almost perpendicular directions, and might have remained in this “stalemate” scenario for millions of years.