Sunday , May 16 2021

Apollo astronauts can bring some of the Ancient Earth from the moon

Lunar sample 14321, also known as Big Bertha.
Picture: NASA

An analysis of the lunar material collected during the Apollo 14 mission resulted in an incredible conclusion: One of the rocks that returned seems to contain a small part of the Earth dating from about 4 billion years. Incredibly, it is now among the oldest terrestrial cliffs, which are known to exist.

A new study published this week in the Earth and planetary scientific scripts argues that the fragment of rocks embedded in the lunar sample 14321-twofold rock known as Big Bertha – is of land origin. The fragment probably reached the surface of the moon after the asteroid or comet collapsed in the Earth, throwing remnants into space. Leading authors of the new study, Jeremy Bellucci of the Swedish Natural History Museum and Alexander Nemchin of Kurtin University in Australia, say that this happened about 4 billion years ago during Haddeon Eon – a time when a young country was regularly hit by large objects.

The Big Bertha was assembled by NASA astronauts Alan Shepard and Edgar Mitchell in 1971 during Apollo 14 million for the formation of Fra Mauro. This rock, along with other lunar specimens, is stored in the moon for betting the object at the Johnson Space Center in Houston, Texas. Example 14321 is special in that it is rich in crystalline crystal matrix.

"In the terminology of the layman, this means that this is a rock made from a jump from pre-existing rocks and stone fragments, as well as melting and percussion material formed during a major impact or series of impacts on the moon," said James Day, a professor at Scripps Institution of oceanography, who was not involved in the new study, said Gizmodo. "The sample is described as" wealth, "which contains many rock clusters."

A lunar sample 14321 with an arrow indicating the location of the apparent fragment of the Earth.
Image: USRA / NASA

Katie Robinson, a postdoctoral associate at the LPI-AD Center for Lunar Sciences and Research and co-author of the new study, said that 14321 was recognized as unusual for a long time, and only now appreciate how unusual it really is. Packed within this lunar breech are 2-gram falsity-fine-granulated fragments of felsite containing volcanic rocks, including quartz, feldspar and zircon. These materials are commonly found on Earth, but are very unusual on the moon. Indeed, a chemical analysis of the sample suggests that it was formed underland, and not from the Moon conditions.

"What we did was use of the composition of minerals in the fragment to show that it was formed under conditions that only occur on Earth," Robinson told Gizmodo. "For example, the composition of certain minerals is sensitive to temperature and pressure, they contain more or less different elements if they crystallize in hot or cold and / or deep or shallow environments. Other minerals may indicate whether the rock is formed in the presence of very oxygen or in a very poor environment.Our data show that this fragment is formed with higher pressure, more rich in oxygen and lower temperature than it happens on the Moon.In fact, it had to come from the environment similar to Earth. "

Obviously, the moon simply happened to have an environment similar to Earth's next door in the shape of the Earth. That the ancient strike of an asteroid could throw pieces of ground residues in space and on the surface of the moon is not a funny idea. Back over the Hadean, asteroids regularly produced craters thousands of kilometers in diameter. The influences of this size were capable of extracting materials from deep into the surface of the Earth. The apparent land fragment found in Big Bertha was formed about 20 kilometers below the surface of the Earth – a depth that is not available for these ancient asteroids.

The image of an asteroid artist struck with the Earth during the time of the Jews.
Picture: Simon Marki

Another possibility, according to the new research, is that the fragment crystallized on the moon. But in order for this to happen, the material was to form deep into the moon near its lunar mantle, and there was no good reason for it to reach the surface. The simpler explanation, say the researchers, is that it comes from the Earth.

Talking about the surface of the moon, it seems strange that Apollo astronauts managed to find this breach so easily. Indeed, billions of years continuously accumulated lunar dust, known as regolith, should close the traces of this rock. But, as Robinson explained, Big Bertha was covered with regolith, simply not enough to bury him completely. To explain her presence on the moon's surface, she says the breach was once buried, but she returned to the surface after a stroke formed by the crater Kun, a crater of about 300 meters near the landing site of Apollo 14 – very honorable process of the moon, "she added.

A fascinating aspect of this discovery is that this lunar sample of apparent land origin is really ancient. The old zirconium mineral found in the sample is 4 to 4.1 billion years old, now among the oldest known ones. The press release of the University of Space Research (UCRA) went so far as to declare it the oldest "earth rock", but that's not entirely true, as Matthew Dude, a geologist at University College London, explained.

"The age of a zirconium mineral found in the lunar sample is quoted as about 4,01 billion years ago, making it a very old piece of Earth (if this research is true), but that's not the oldest," Dodd told Gizmodo. "There are 4.3 billion to 4.3 billion years old cirques on the Earth that come from Western Australia."

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The authors of the new study presented two possibilities to explain the anomalous sample: either formed on Earth (very likely) or formed deep into the moon (very unlikely). But Dan said the researchers missed a third chance.

"It is that these unusual features are the result of the impact of Moon processes, without the need to come from these rocks from the Earth," he told Gizmodo. "During the formation of melt blows, conditions can be created for generating the unusual chemical structure of the traces of zircons, but this possibility is not considered by the authors, although these flexible coatings have textures in accordance with melting of rocks, including melting and brewing. "

Dan said his scenario looks more likely compared to the "required chain of events" [breaking] flying from the Earth at very high impact pressures so that it can escape the orbit of the Earth and then incorporate it into a lunar smelting stone. "Felsity breasts, he said, are almost the right age for" some of the earliest recorded major impacts on the moon, with greater likelihood of lunar origin ".

For the authors of the new study, this type of return or criticism is not unexpected. As stated in the press release of the USRA, the researchers fully predict that "the conclusion of land origin for the fragment of the rocks will be controversial".

When they reached the comment, Bellucci said some of his peers were likely to be skeptical just because the specimens were found on the moon. But he said "the best explanation for our data presented in the paper is terrestrial origin for the analyzed areas," adding that, as he and his colleagues know, "we did the best thing we could do to confirm terrestrial origin."

To which Robinson further elaborates: "We know from dynamic calculations that the Earth's specimens were definitely thrown out during strokes and reached the moon, but the challenge is in recognizing them," she said. "This is just the first rock identified as the terrestrial meteorite. The more we find, the better we get to identify them!"

Despite Dan's reserves, he said the new study was important in highlighting the need for future missions to study the formation of the moon.

"Returning to the moon to understand how it is formed and how our own planet will form, will be a scientific incentive, just as the missions of the US Apollo and the Soviet Moon on the Moon returned in the late 1960s and early 1970s "said Dan. "Ultimately, as this paper shows in 2019, we are still making discoveries about the moon of cliffs collected 48 years ago."

[Earth and Planetary Science Letters]

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