The Moon Is Making Days On Earth Longer

Counting down the minutes until the end of the day? Thanks to our moon, the process is going to be taking increasingly longer each time.

How The Moon Affects Time

The moon is drifting farther and farther away from the Earth by about 1.5 inches every year. This phenomenon causes the rotation of the planet to slow down ever so slightly on its axis. Here on Earth, the effect is that each day is getting longer.

"As the moon moves away, the Earth is like a spinning figure skater who slows down as they stretch their arms out," co-author Stephen Meyers, a geoscience professor at University of Wisconsin-Madison, describes in a statement.

This isn't a new development, though. Research says that the moon has been responsible for lengthening Earth days since 1.4 billion years ago when each day lasted just 18 hours.

Study Reveals Earth And Moon's Long History

A new study, co-authored by Meyers and published in the journal Proceedings of the National Academy of Sciences on Monday, June 4, made use of astrochronology, which is the combination of astronomical theory and geological observations. With this method, scientists are able to dig deep into the Earth's past and turn back the clock, in a sense.

Data show, for example, that more than 1.5 billion years ago, the moon was actually so near the planet that Earth's gravity would have actually ripped the moon apart. Since the moon has existed for 4.5 billion years — and is still around — the scientists knew they were missing something.

Meyers and co-author Alberto Malivarno developed the specific approach that accounts for the uncertainty through time. With their system, they were able to analyze billions-year-old rock layers to determine the distance between the planet and moon as well as the length of each Earth day back then.

"One of our ambitions was to use astrochronology to tell time in the most distant past, to develop very ancient geological time scales," Meyers explains, saying that the goal was to be equipped to study rocks billions of years old in the same way that they can study modern geologic processes.

The team's work revealed that 1.4 billion years ago, the moon was much closer to Earth so the planet was able to spin a lot faster on the axis.

While their findings are already impressive, the team isn't quite done yet. Malinverno says that they are planning on expanding their work to varying intervals in geologic time.