Once upon a time, when the moon was closer to our planet, a day only had 18 hours. According to the University of Wisconsin-Madison researchers, about 1.4 billion years ago, the moon was orbiting Earth a lot closer than it is now, altering the way it spins on its axis. What’s even more interesting is that according to them, the moon will keep on moving further away from our planet, making days even longer than they are now. Stephen Meyers, the leader of this new study which the journal Proceedings of the national Academy of Sciences published, says that when the moon moves away, Earth becomes like a figure skater who stretches their arms out, slowing down.
Meyers and his team wanted to know how the moon’s orbit affects Earth’s rotation. So, they used astrochronology, a method that connects both astronomical theory with geological observation. This was how they were able to reconstruct our solar system’s ancient history. The team’s very ambitious goal was to develop some ancient geological time scales. This way, they were able to study ancient rocks the same way they study modern geologic processes.
Why days are longer now than in the past
In our solar system there is something called the Milankovitch cycles which is the way a gravitational field affects other celestial bodies. They’re so strong that they can even affect the environment on Earth. They are able to impact how sunlight gets distributed on our planet. Meyer and his team also analyzed some sediments in a 90 million-year-old rock. This offered them information on the planet’s climate cycles.
Currently, the moon is moving away from Earth with 3.82 centimeters each year. So, humans won’t have to worry about recalculating the length of a day now. It will take hundreds of millions of years until this becomes important.
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