We've all complained that there aren't enough hours in the day, and apparently the Moon has always been listening. New research shows that days on Earth are getting longer, and this phenomenon can be attributed to the Moon's slow drift away from Earth, Space.com reports.
Researchers at the University of Wisconsin-Madison determined that 1.4 billion years ago, when the Moon was closer to us, a day on Earth lasted about 18 hours. Each year, the Moon moves about 1.5 inches away from our planet, mainly due to Earth's tidal forces. As the Moon grows more distant, Earth rotates more slowly around its axis "like a spinning figure skater who slows down as they stretch their arms out," Stephen Meyers, the study's co-author, explained in a statement.
However, we won't notice the difference while we're alive—and neither will our great-great-grandchildren, for that matter. A few years ago, astronomer Britt Scharringhausen estimated that in 100 years, the day will be two milliseconds longer.
The scientists at UW reached their findings, which were published in the journal Proceedings of the National Academy of Sciences, by drawing on astronomy and geology. Using a statistical method called astrochronology, they studied two rock formations in China and the Atlantic Ocean that date back 1.4 billion and 55 million years, respectively, to better understand the ancient history of the Earth.
"The geologic record is an astronomical observatory for the early solar system," Meyers explained. "We are looking at its pulsing rhythm, preserved in the rock and the history of life."
Variations in Earth's movements—known as Milankovitch cycles—are determined not just by the Moon, but also by the other planets. This ultimately determines the amount of sunlight that reaches Earth and affects our planet's climate.