Days on Earth are getting longer, courtesy of Moon moving farther away from the planet
Earthlings are set to experience longer days albeit very slowly, all thanks to the planet’s interaction with the moon. According to a new research co-authored by Stephen Meyers, Ph.D.,at the University of Wisconsin-Madison, and Alberto Malinverno, Ph.D., a research professor at Columbia University’s Lamont-Doherty Earth Observatory, the moon is currently moving away from the Earth at a rate of 3.82 centimeters per year adding 2 milliseconds to Earth days every century.
To cite an analogy, the Earth reacts like a spinning figure skater who slows down as she stretches her arms out; the rotation slows. That means days have kept getting longer.
Moon’s movements are part of a grand cycle of planetary motions influencing everything from the length of our days to long-term climate change. Prof. Meyers and his team used astrochronology, (the statistical method that connects astronomical theories with geological observations), to reconstruct the solar system's ancient history. It shows that 1.4 billion years ago, a day on Earth lasted about 18.7 hours. Days have since gradually lengthened.
The record of orbital changes can be extended to time intervals much older than those explored so far. This will allow for reconstructing fundamental characteristics of the Earth-moon system and of other planets in the Solar System in deep time, quoted coauthor of the study Alberto Malinverno.
Earth’s rotation and revolution both are actively influenced by Milankovitch cycles (variations in eccentricity, axial tilt, and precession of the Earth's orbit). In an effort to reconstruct the cycles further back in time than researchers have ever been able to before, the geoscientists united records of Milankovitch cycles with geological records by an aid of a new computer model. The conclusion was the fact that the moon’s gradual drift away from Earth is causing the planet’s rotation to slow down, which in turn is steadily stretching out the length of our days.
This increase however is very subtle and it will take around 200 million years before a full hour is added to the current Earth day. If humans are fortunate to be still alive and kicking by then, the length of a day will have to be recalculated from 24 hours to 25 hours. So the Moon really seems to be the hotbed of many interesting happenings.
The study adds to a growing body of recent astrochronology-related findings and was published this week in the Proceedings of the National Academy of Sciences.
Source: Columbia University