A recent study published in Nature has suggested that the moon is much older than previously estimated. According to this research, the moon could have formed 4.51 billion years ago, which is about 100 million years older than the widely accepted age of 4.35 billion years. This new timeline not only changes our understanding of the moon’s history but also provides new insights into the early solar system.
Moon could have formed 4.51 billion years ago; new theory suggests
The secret of the theory lies in re-melting. The Earth’s gravity gave some new resetting to the lunar rocks, and the clock’s geological “ticking” of the moon’s outer surface was affected. As says Francis Nimmo, leading research professor at the University of California, the lunar surface rocks do not date in the sense of marking a historical time when the moon was formed; they rather demonstrate later occurrence of the re-melting event. This remelting occurred when the gravitational forces of Earth worked to put stress on the moon, heating its interior.
It is on this principle that Nimmo’s team presents the proposal of gravitational interaction between Earth and the moon that caused such great internal changes in the rock formations which resulted in resetting. This later remelting of rocks, beyond the formation period of the moon, is the cause why these previous methods to estimate the age of the moon had overlooked these changes.
An old assumption of moon’s age
Scientists had long believed that the moon was born 4.35 billion years ago from a gigantic collision between Earth and a Mars-sized object. This was termed the giant impact hypothesis since it explained how the debris of the impact coalesced into the moon. The moon was relatively young in age according to samples of lunar rocks that were returned by the Apollo missions, which were used to estimate its time of formation.
However, the new study challenges those assumptions made earlier by suggesting a different sequence of events, especially one that points to a re-melting event that might have reset the age of lunar rocks.
New evidence from Zircon supports an older moon formation
Another way this new hypothesis is corroborated is with the mineral evidence on the moon, specifically by looking at the zircon. It is now known to date to some 4.5 billion years of the Earth-moon forming event, originally assumed to be from its origin. Instead, this most recent study tells scientists that zircon may date to far before this original moon-building date.
The study attributes the findings to tidal heating. This occurs when Earth’s gravitational forces cause frictional forces on the moon, which will in turn warm the interior. This occurs the same way as what happens for Jupiter’s moon Io, with a constant force of gravitation from the planet which leads to a lot of heating within the interior of the moon. Just like Io experiences tidal heating due to orbital interactions with Jupiter, so the moon would have had tidal heating from Earth’s gravitational forces.
The new understanding of geology has good evidence to suggest the moon formed far earlier than believed. Even the theories for re-melting and tidal heating could give reason why the lunar minerals are much older than the time that the moon is assumed to have formed.
Conflicting theories on the moon’s age are resolved by new research
For decades, the moon’s age has been debated over several conflicting theories. The samples brought by Apollo were thought to suggest a younger moon, which had been further supporting the idea of a 4.35-billion-year-old satellite. However, according to the new research carried out by Nimmo and his team, the formation timeline of the moon is instead older, about 4.51 billion years. This shift brings in harmony many conflicting views and adds a new dimension to our understanding of the geological history of the moon.
Origin of moon
The origin of the moon is an important area to study for future space research. Future lunar missions, which include China’s Chang’e 6 and NASA’s Artemis program, will presumably yield additional samples and information that could be used in refining our understanding of how old and how long in the past the moon was formed. In other words, these missions will give scientists a lot more material to consider, which will help them come to conclusions about confirming or challenging the latest findings.
As these new missions are closer to the moon’s surface, researchers will be able to further discover how it was formed early on and how it geologically developed along with the processes that currently govern its state.
Implications on formation of moon
This study has greater implications beyond just the moon. According to Carsten Munker, a researcher from the University of Cologne, “The history of the moon is important for understanding the origin of the solar system as well.” The study about the age of the moon provides insights into the early tumultuous times of the solar system where planets and moons were forming.
By pinpointing key events like the moon’s formation and the role of tidal heating, scientists can gain a deeper understanding of how the planets and their satellites came to be. The difference between 4.35 billion years and 4.51 billion years might seem small, but it is crucial for our knowledge of solar system history.
New moon age timeline offers insights into early solar system
The difference may seem negligible between 4.35 and 4.51 billion years, but it opens up new opportunities for understanding the early solar system and the processes that shaped our closest celestial neighbor. Such a new timeline also focuses on further exploration to help refine our understanding of the moon and its geological past. By knowing the origin of the moon, we also come to know the early Earth history and that of the rest of the solar system. In this way, we would have known the origin of our cosmic environment.
Also Read | ISRO starts assembly of HLVM3 for Gaganyaan mission at SDSC for first uncrewed flight
