We all learned in our science classes that one complete rotation of the Earth on its axis takes 24 hours, marking the length of a day. However, this may not always be the case. A recent study by scientists at the University of Wisconsin-Madison suggests that Earth’s days could stretch to 25 hours in the distant future due to the Moon’s gradual drift away from our planet.
The Moon, Earth’s closest celestial neighbor, has a significant influence on our planet’s rotation. As it slowly drifts away from Earth, this movement affects the Earth’s rotational speed, causing it to slow down. To understand this phenomenon, let’s take a journey back in time. Around 1.4 billion years ago, a day on Earth lasted only 18 hours. Since then, the rotational speed of our planet has been gradually decreasing as the Moon continues to move further away.
This intriguing relationship between Earth and the Moon was uncovered by scientists who analyzed ancient rock formations dating back 90 million years. These rocks provided critical insights into the Earth’s historical rotational patterns and the Moon’s influence on them. Today, the Moon is approximately 384,400 kilometers away from Earth and takes about 27.3 days to complete one orbit around our planet.
Stephen Meyers, a professor of geoscience at the University of Wisconsin-Madison, offered a fascinating analogy to explain the situation: “As the moon moves away, the Earth is like a spinning figure skater who slows down as they stretch their arms out.” This gradual slowing of Earth’s rotation is a direct consequence of the Moon’s increasing distance. Meyers also notes that if the Moon had been closer to Earth about 1.5 billion years ago, its gravitational interactions would have been so intense that they could have torn the Moon apart.
The study reveals that the Moon is currently moving away from Earth at a rate of 3.82 centimeters per year. If this trend continues, Earth could experience 25-hour-long days approximately 200 million years from now. This is part of what scientists refer to as the “Milankovitch cycles,” which are long-term variations in Earth’s orbit and axial tilt that affect the distribution of sunlight on our planet, influencing climate rhythms over millennia.
The research was led by Professor Stephen Meyers in collaboration with Alberto Malinverno, a research professor at Columbia University. Malinverno developed a statistical approach called TimeOptMCMC, which allowed the team to assess variations in the geological record and understand the relationship between the length of Earth’s days and the Moon’s distance from Earth.
While the prospect of 25-hour days may seem far off, this study sheds light on the intricate and evolving relationship between our planet and its natural satellite, offering a glimpse into the long-term future of Earth’s rotation.