Washington, The relationship between the Earth and the Moon has inspired several generations of poets, writers and scientists, with some imagining them to be long lost lovers, while others questioning their effects on life on this planet.
Keeping the rhetoric aside, the geoscientists at the University of Wisconsin-Madison have found that 1.4 billion years ago, a day on Earth lasted just over 18 hours. This was at least in part because the moon was closer and changed the way Earth spun around its axis.
“As the moon moves away, the Earth is like a spinning figure skater, who slows down as they stretch their arms out,” explained Stephen Meyers, professor of geoscience at the University of Wisconsin-Madison and co-author of the study published last week in the Proceedings of the National Academy of Sciences.
It describes a tool, a statistical method, that links astronomical theory with geological observation (called astrochronology) to look back on Earth’s geologic past, reconstruct the history of the solar system and understand the ancient climate change, as captured in the rock record.
“One of our ambitions was to use astrochronology to tell time in the most distant past, 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,” Mr Meyers told the Science Daily.
Last year, Meyers and colleagues cracked the code on the chaotic solar system in a study of sediments from a 90 million-year-old rock formation that captured Earth’s climate cycles. Still, the further back in the rock record he and others have tried to go, the less reliable their conclusions.
For instance, the moon is currently moving away from Earth at a rate of 3.82 centimeters per year. Using this present day rate, scientists extrapolating back through time calculated that “beyond about 1.5 billion years ago, the moon would have been close enough that its gravitational interactions with the Earth would have ripped the moon apart,” Prof Meyers explained.