Caption: Image of Mare Imbrium taken during the Apollo 17 mission in 1972, showcasing the Pytheas and Copernicus craters. (Credit: NASA)
Scientists have successfully resolved the discrepancies in dating methods for the Moon’s surface, unveiling that certain regions of its crust are approximately 200 million years older than previously believed. This revised dating approach, achieved through a comparison of Apollo samples with crater counts and spectroscopy data from various lunar missions, carries significant implications for our comprehension of the early geological history of the Moon, Earth, and the origins of life.
By “resetting the clock” for lunar craters, researchers have determined that specific areas of the Moon’s surface, often associated with the iconic “Man in the Moon,” are roughly 200 million years older than previously assumed.
A collaboration between Norwegian and French scientists has established a method to coordinate and recalibrate two conflicting systems of dating the Moon’s surface. This novel evaluation has revealed that substantial portions of the lunar crust are approximately 200 million years older than originally estimated, enabling scientists to clarify the sequence of events in the Moon’s surface evolution.
Unlike the Earth, which experiences continuous geological activity, the Moon is now relatively geologically inactive. Consequently, the craters resulting from asteroid and comet impacts have not eroded away over time. Earth, despite undergoing a similar barrage of impacts, has had its surface movements conceal these impacts.
Presenting their findings at the Goldschmidt Geochemistry Conference in Lyon, Professor Stephanie Werner from the Centre for Planetary Habitability at the University of Oslo shared, “Analyzing the signs of these impacts on the Moon provides insights into what Earth would be like without the geological activity of plate tectonics that occurred here. We have demonstrated that large portions of the lunar crust are around 200 million years older than previously thought.”
Scientists were aware that the conventional method of determining the age of the Moon’s surface, known as crater counting, yielded different results compared to the analysis of rocks retrieved during the Apollo missions, particularly concerning the lighter regions on the Moon’s surface known as the Highlands.
“We recognized the need to reconcile these differences, which involved correlating individually dated Apollo samples with the number of craters in their respective areas. Essentially, we reset the crater clock. Additionally, we cross-referenced them with spectroscopy data from various Moon missions, with a special focus on the Indian Chandrayaan-1 mission, to accurately assign each Apollo sample to its corresponding surface area for crater counting. This undertaking was extensive, as we commenced this project in 2014. However, through this approach, we successfully resolved the discrepancy and pushed back the age of the Moon’s surface by up to 200 million years,” Professor Werner explained.
As an example, the age of the Imbrium Basin, which contains the lunar sea called Mare Imbrium (visible in the top left of the Moon), and is believed to have formed from the collision of an asteroid with a size similar to Sicily, has been revised from 3.9 billion years ago to 4.1 billion years ago. The researchers emphasize that this adjustment does not impact estimates of the Moon’s overall age but only pertains to the age estimation of its surface. The new dating system modifies the age of various regions on the Moon’s surface, although not uniformly, with the oldest areas experiencing the most significant changes.
Professor Werner noted, “This difference is of significant importance. It allows us to trace back in time an intense period of space bombardment that occurred before extensive volcanic activity shaped the patterns we associate with the ‘Man in the Moon’—the mare volcanic plains, including Mare Imbrium. As this bombardment transpired on the Moon, it is highly likely that Earth also endured a similar period of earlier bombardment.”
Professor Audrey Bouvier from the University of Bayreuth in Germany, who was not involved in the study, commented, “The Moon provides unique records of the early bombardment history. Through successful lunar sample return programs such as Apollo, Luna, and Chang’e, which enabled the association of rocks with their specific sampling locations on the Moon, Professor Werner and her colleagues have significantly extended the records of heavy bombardment on the terrestrial planets.”
This period of intense bombardment likely influenced the origin and early evolution of life on Earth and potentially on other planets like Mars. The next significant leap in the search for signs of ancient life on another planet within the Solar System would involve retrieving rock samples from Mars’ Jezero Crater.
Note: The work presented in this article is based on the following research, which is in press at the peer-reviewed publication, The Planetary Science Journal:
- Bultel, B. S.C. Werner (2023). Sample-Based Spectral Mapping Around Landing Sites on the Moon – Lunar Time Scale Part 1. The Planetary Science Journal, in press.
- Werner, S.C., B. Bultel, T. Rolf (2023). Review and Revision of the Lunar Cratering Chronology – Lunar Time Scale Part 2. The Planetary Science Journal, in press.
Table of Contents
Frequently Asked Questions (FAQs) about Lunar surface dating
What did the researchers discover about the age of the Moon’s surface?
The researchers discovered that parts of the Moon’s surface, which are associated with the “Man in the Moon” character, are approximately 200 million years older than previously believed. They reconciled conflicting dating methods and pushed back the age of the Moon’s crust.
How did the researchers reconcile the differences in dating methods?
The researchers coordinated and recalibrated two conflicting systems of dating the Moon’s surface. They compared Apollo samples with crater counts and spectroscopy data from various Moon missions, such as the Indian Chandrayaan-1. This extensive work allowed them to resolve the discrepancies and refine the dating of the Moon’s surface.
Does this change the overall age of the Moon?
No, the revised dating method only affects the estimation of the Moon’s surface age, not its overall age. The researchers emphasize that the new dating system modifies the age of different areas on the Moon’s surface, but not uniformly.
What implications does this have for our understanding of Earth’s history?
Studying the Moon’s surface impacts provides insights into what Earth would be like without plate tectonics. The findings suggest that Earth likely experienced a similar intense period of space bombardment in its early history, which could have influenced the origin and early evolution of life on our planet.
How does this research contribute to future space exploration?
Understanding the Moon’s early bombardment history helps scientists anticipate the impact events that terrestrial planets, like Mars, may have experienced. Retrieving rock samples from other planets, such as Mars’ Jezero Crater, will provide valuable information in the search for signs of ancient life beyond Earth.
3 comments
The Moon’s surface age got a makeover! Scientists figured out it’s 200 mil yrs older than thought. They matched Apollo rocks, craters, and spectra from missions. Imagine Earth before plate tectonics! Could Mars hold ancient life secrets? Bring on those rock samples!
wow scientists reset the moon crater clock & stuff, found it’s surface is 200 mill yrs older! cool! like, they compared rocks from Apollo missions with craters & spectra data from moon missions. intense bombardment b4 man in moon patterns! Mars rocks next!
Mind-blowing discovery! The Moon’s surface is way older than we thought. By comparing Apollo rocks, crater counts, and moon mission data, scientists reset the clock. Heavy space bombardment, cool mare plains, and impacts on Earth too. Can’t wait for Mars samples!