A lunar probe launched by the Chinese space agency recently brought back the first fresh samples of rock and debris from the Moon in more than 40 years.
New Delhi: A lunar probe launched by the Chinese space agency recently brought back the first fresh samples of rock and debris from the Moon in more than 40 years. Now an international team of scientists – including an expert from Washington University in St. Louis – has determined the age of these moon rocks to be about 1.97 billion years.
The findings of the study were published in the journal ‘Science’. “This is the perfect specimen to close a 2-billion-year gap,” said Brad Joliff, the Scott Rudolph Professor of Earth and Planetary Sciences in the Arts and Sciences and director of the university’s McDonnell Center for Space Science. Jolliff is a US-based co-author of the analysis of new moon rocks led by the Chinese Academy of Geological Sciences.
The age determination is one of the first scientific results reported from the successful Chang’e-5 mission, which was designed to collect and return Earth rocks from the youngest volcanic surfaces on the Moon. “Of course, ‘young’ is relative. All the volcanic rocks collected by Apollo were over 3 billion years old. And all the young impact craters whose age has been determined from the analysis of samples are less than 1 billion years old. So The Chang’e-5 samples fill an important gap,” Jolliff said.
The difference Jollif noted is important not only for the study of the Moon but also for the study of other rocky planets in the Solar System.As a planetary body, the Moon itself is about 4.5 billion years old, almost as old as Earth. But unlike Earth, the Moon doesn’t have the erosive or mountain-building process that eroded craters over the years. Scientists take advantage of the Moon’s permanent craters to develop methods to estimate the age of different regions on its surface, based on how much of the region is affected by the crater.
This study showed that the moon rocks returned by Chang’e-5 are only about 2 billion years old. Knowing the age of these rocks with certainty, scientists are now able to calibrate their important chronological instruments more precisely, Jolliff said.
“Planetary scientists know that the more craters on the surface, the older it is; the fewer craters, the younger the surface. That’s a good relative determination. But to put absolute age dates on that, it’s important to take samples from those surfaces. Will be,” said Jolliff.
“The Apollo samples gave us several surfaces that we were able to date and correlate with crater density. This cratering chronology has been extended to other planets – for example, to Mercury and Mars – to say that a Craters with fixed density surfaces have a certain age,” Jolliff explained. “In this study, we got a very precise age, around 2 billion years, plus or minus 50 million years. This is an unprecedented result. In terms of planetary timing, it’s a very accurate determination. And it’s different.” – enough to distinguish between different chronological threads,” said Jolliff.
Other interesting findings from the study relate to the composition of basalt in the returned samples and what this means for the lunar volcanic history, Jolliff said.
The results are just the tip of the iceberg, so to speak. Jolliff and his colleagues are now going through regolith samples for keys to other important lunar science issues, such as bits and pieces dumped from afar in the Chang’e 5 collection site, young impact craters such as Aristarchus. , possibly the nature of the material on these younger rocks and those other impact sites, to determine the age. Jolliff has worked with scientists at the Sensitive High Resolution Ion Microprobe (SHRIMP) Center in Beijing that led the study, including study co-author Duni Liu, for more than 15 years. This long-term relationship is made possible through a special cooperation agreement involving the University of Washington and its Department of Earth and Planetary Sciences, and Shandong University in Weihai, China, with support from the University of Washington’s McDonnell Center for the Space Sciences.
“The laboratory in Beijing where the new analyzes were conducted is one of the best in the world, and they have done an exceptional job characterizing and analyzing the volcanic rock samples,” Joliff said. “The consortium includes members from China, Australia, the US, the UK and Sweden. It is science done in an idealized way: with an international collaboration, free sharing of data and knowledge – and all done in the most collegial way possible This is diplomacy by science,” Joliffe continued.
Jolliff is an expert in mineralogy and has provided his expertise for this study of the Chang’e-5 specimens. He has a personal research background Centered on the Moon and Mars, the materials that make up their surfaces and what they tell about the history of the planets.
As a member of the Lunar Reconnaissance Orbiter Camera Science Team and leader of the University of Washington team in support of NASA’s Apollo Next Generation Sample Analysis (ANGSA) program, Jolliff investigates the surface of the Moon, exploring what can be seen from orbit, is related to. The Moon is known through the study of lunar meteorites and Apollo samples – and now, from the Chang’e-5 samples.
First published:October 10, 2021, 2:36 PM