September 30, 2023

Famous ‘man on the moon’ may be 200 million years older than we thought

    An image of Mare Imbrium taken from Apollo 17 in 1972. To the left of center is the Pytheas crater.  Near the top is the Copernicus crater.

An image of Mare Imbrium taken from Apollo 17 in 1972. To the left of center is the Pytheas crater. Near the top is the Copernicus crater.

The “Man in the Moon” is older than we thought.

Scientists have proposed resetting the lunar clock after reassessing the impact craters on the moon’s surface. This means that some features of the moon, such as the formation that makes up the face of the “Man in the Moon” formation, may be 200 million years older than previously believed.

The new dating system could help better tell the story of the evolution of the lunar surface and has important implications for our understanding of the violent and turbulent early history of the solar system in which bodies such as the Earth and moon were subjected to intense bombardment by space. rocks.

Related: The Moon: Everything you need to know about Earth’s companion

The new evaluation involved reexamining two separate ways of dating the lunar surface: counting the number of craters caused by space rock impact; and the assessment of moon rocks collected by the Apollo missions. These two dating methods have historically yielded different results, especially for the ages of the moon’s heavily cratered and mountainous highlands.

“We decided we had to reconcile these differences, and that meant correlating individually dated Apollo samples with the number of craters in the vicinity of the sample site — essentially resetting the crater clock,” Center for Planetary Habitability, University of Oslo, Professor Stephanie Werner, speaking at the Goldschmidt Geochemistry Conference in Lyon, said: “We also correlated them with spectroscopy data from several lunar missions, especially the Indian Chandrayaan-1, to make sure which Apollo sample belongs to the surface in which we see craters. have counted.”

Like the moon, Earth also experienced a high number of space rock impacts during the turbulent early years of the solar system, but a similar dating method for counting craters wouldn’t work on our planet. That’s because geologic processes like shifting tectonic plates have masked its impact record.

The moon, on the other hand, is quite geologically inactive, and that means that instead of being eroded away, the record of the impacts it experienced is frozen in the lunar surface.

“Looking at the signs of these impacts on the moon shows what the Earth would look like without the geological churning of plate tectonics that happened here on Earth,” Werner said. “What we’ve done is show that large parts of the lunar crust are about 200 million years older than previously thought.”

A lunar clock reset with a major impact

The team behind the findings explains that the new dating system doesn’t change estimates of the age of the moon as a whole, which remains about 4.53 billion years old. Instead, it changes the age of all parts of the lunar surface, but not in a uniform way; the new dating system suggests that older areas are subject to the greatest age shift as a result of the new system.

An example of the extreme age differences discovered by Werner and colleagues can be seen in the 712-mile (1,146 kilometers) wide Imbrium Basin, an ancient impact site believed to have been created when a New Jersey-sized asteroid hit the moon touched somewhere in its distant past. The basin was filled with impact debris and volcanic material after its formation, creating a vast lava plain called the Mare Imbrium.

a large crater on the surface of the moon

a large crater on the surface of the moon

Previous estimates had put the age of the asteroid impact at about 3.9 billion years, but the team’s results pushed the impact and the formation of the Imbrium Basin back 200 million years to 4.1 billion years ago.

“This is an important difference. It allows us to push back in time an intense period of bombardment from space that we now know occurred before extensive volcanic activity that created the ‘Man in the moon’- formed patterns — the mare volcanic plains, including Mare Imbrium,” Werner said. “Since this happened on the moon, Earth was almost certain that it had also suffered from this earlier bombardment.”


– What lunar craters can tell us about Earth and our solar system

— Massive granite ‘body’ on the far side of the moon offers evidence of ancient lunar volcanoes

— How did the moon form?

Audrey Bouvier, a researcher from the University of Bayreuth, was not involved in the work, but she explained how the moon provides unique data about early bombardment history in the solar system and how this dating change could rethink our understanding of
planetary evolution.

“Such a heavy bombardment period must have influenced the origin and early evolution of life on Earth and possibly other planets such as Mars,” Bouvier said in a statement. “Bringing back rock samples from Jezero Crater on Mars will be the next big step forward in looking for signs of ancient life on another planet in the solar system, and when.”

The team’s research was presented at the Goldschmidt conference held in Lyon, France, between July 9 and July 14. It has been accepted for publication in the Planetary Science Journal.

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