Moon formation: New spins put on old questions (Earth, theory, slowing)

[Brian.Pearson]

Scientists have put a new turn on the theory of how the Moon was created.

[Glitch]

This is not a "new turn on the theory." We have known for quite some time that as a result of tidal forces the moon has been slowing Earth's rotation by about 12 microseconds per year. Around 650 million years ago the Earth was rotating at around 22 hours per day. Three to four billion years ago the Earth was rotating somewhere between 12 and 16 hours per day. Before the impact with Thea it is estimated that the Earth was rotating around 8 hours per day.