If you sometimes feel like your days are getting longer, that could be because they are -- and it's all down to our Moon.
NASA and other scientists have stated that the Moon is slowly drifting away from Earth. But this cosmic drift isn't just some fascinating space trivia, but has massive ramifications on Earth's day length and climate rhythms.
As the moon pulls away, its gravitational hold on our planet weakens, slowly leading to longer Earth days.
During the Apollo 11 missions back in 1969, astronauts installed reflective panels in the Sea of Tranquillity on the Moon. Scientists then used what was called the Lunar Laser Ranging Experiment to determine that the Moon is slowly drifting away from Earth at a rate of about 3.8 centimeters every year.
Now, new groundbreaking research has thrown some light on the dynamics of Earth-moon relations and how they've evolved over billions of years. Professor Stephen Meyers, co-author of the study from the University of Wisconsin-Madison, describes the process succinctly (via Daily Mail): "As the moon moves away, the Earth is like a spinning figure skater who slows down as they stretch their arms out."
Astronomy.com editor Caitlyn Buongiorno broke down the science, explaining: "It boils down to one of Newton's laws - conservation of angular momentum.
"As the Moon’s gravity pulls on Earth, it produces tidal forces that make the oceans bulge and cause Earth's rotation to lose momentum." She adds that if the Moon keeps drifting away at the current rate, "it should take about 50 billion years before the Moon takes as long to complete one orbit as Earth takes to complete one rotation."
The research uses a sophisticated statistical technique called astrochronology; a blend of astronomical theory and geological observation. With this method, Meyers and his team could peer back into Earth's geologic history and accurately reconstruct how our modern human constructs of time behaved in our solar system billions of years ago.
Credit: Xia Yuan / GettyMeyers says: "One of our ambitions was to use astrochronology to tell time in the most distant past, to develop very ancient geological time scales. We want to be able to study rocks that are billions of years old in a way that is comparable to how we study modern geologic processes."
As a result, astrochronology has allowed scientists to observe that days on Earth lasted just over 18 hours around 1.4 billion years ago. The reason? A closer moon exerted a stronger gravitational pull, making Earth spin faster —- six hours faster each day.
All celestial bodies - including planets and their moons - influence one another's movement in space. This intricate dance of gravitational pulls causes variations in planetary rotations, known as Milankovitch cycles. These cycles play a pivotal role in determining Earth's climate rhythms.
Still, dating this far back has its limitations. For instance, while the moon is currently drifting away at a rate of 1.5 inches per year, using this rate to extrapolate back would suggest the moon would have torn itself apart 1.5 billion years ago, conflicting with its actual age of 4.5 billion years. The research was able to correct this by studying layers of rock from different periods. "It was exciting because, in a way, you dream of this all the time; I was a solution looking for a problem," Mayers said.
The study examined rock formations like the 1.4 billion-year-old Xiamaling Formation from Northern China and a 55 million-year-old record from the Walvis Ridge in the southern Atlantic Ocean. Studying these formations helped determine the direction of the axis of rotation of Earth and the shape of its orbit.
Published in the Proceedings of the National Academy of Sciences, this study isn't just an "out-of-this-world" fascination. It underscores how interconnected and dynamic our solar system is, revealing ancient rhythms "preserved in the rock and the history of life," as Professor Meyers explained.
So the next time you look up at the night sky, remember: the moon you're seeing is ever-so-slightly farther away than it was yesterday.
