Scientists have been able to reconstruct the distance between the Earth and Moon 2.46 billion years ago, by studying cycle patterns in rock layers.
“Today, this distance is around 384,300 kilometres. On average, of course, because the Moon doesn’t make a perfect circle around the Earth; its orbit is an ellipse. During the time interval that we studied, the Earth-Moon distance was a lot shorter: around 321,800 kilometres.“
– Margriet Lantink, Earth Scientist at Utrecht University
By analyzing the cycle patterns of the ‘banded iron formations’ in Western Australia, they could determine the distribution of solar radiation that Earth received (the Milankovitch cycles).
From the cycle pattern they also discovered a slower shift due to the ‘tidal evolution’ of the Earth-Moon system and the distance between them in the past.
Lantink could also establish the length of an early Earth day to be 17 hours, rather than the current 24, as the rotation of Earth around its axis slows down over time.
