High burn continues!New research on chang ‘e-5 “local specialties” is underway

2022-06-16 0 By

Important research achievements of Chang ‘e-5 samples have been selected as one of the top 10 scientific and technological developments in China in 2021 by academicians of the Chinese Academy of Sciences and Chinese Academy of Sciences.On Oct. 19, the Chinese Academy of Sciences released the latest research results of the Chang ‘e-5 lunar research sample.Led by the Institute of Geology and Geophysics of the Chinese Academy of Sciences and the National Astronomical Observatories, the breakthrough on important scientific issues surrounding the evolution of the moon was reported in three nature papers and one National Science Review paper.Yang Wei, a key member of the team and a researcher at the Institute of Geology and Geophysics of the Chinese Academy of Sciences, recently revealed in an exclusive interview with Sciencenet.com that they are carrying out the second and third batch of chang ‘e-5 lunar samples and are looking forward to new harvest.Acta Scientia Sinica: As we know, Chang ‘e-5 returned to earth on December 17, 2020, bringing back 1,731 grams of “local products” from the moon.How is the “earth” on the moon different from earth?Yang Wei: The sample we got was in a quartz glass bottle, and it looked like earth.A closer look reveals a big difference.For one thing, zooming in shows that earth’s soil is rounded, but the moon’s soil grains are all sharp and angular, reflecting a distinct difference in weathering between the moon and Earth.Second, lunar samples have a signature “glue.”The moon’s mineral rocks would have been heated and melted as they were crushed by meteorites, and the melted droplets would have bonded together to form a bond with bubbles.This kind of glue has only been found in lunar samples, and once we find it, we can pretty much assume it’s from the moon.In addition, the lunar samples also have a wide range of particle size, ranging from millimeters to nanometers.Chinese Journal of Science: In July 2021, the China National Space Administration (CNSA) distributed lunar samples for scientific research for the first time.What did your research team do first after getting these samples?Yang Wei: After getting the samples, we first sorted out basalt particles.The work is done under a microscope, which is not easy, and people who have not been trained for a long time will have shaky hands.Ma Hongxia, a teacher in our research team, is an expert in sample sorting. She has been doing this work for 15 years.I’m fine with picking bigger particles, but below 200 microns it’s hard to control.Especially when I got the sample for the first time, because a lot of my team and I had been waiting for it for years, and I was working in the lab, and there were a lot of people waiting outside the door with their heads out, wondering what it was like inside the lab.At that time, the mood is very “burning” very excited, hand shaking more severe.After the selection, we glue the sample with resin and then cut it in the middle to make a flat surface for further study.Acta Scientia Sinica: You’ve been “waiting” for lunar samples for years?Yang Wei: Yes.Our Institute of Geology and Earth has been preparing since 2006, deploying a series of advanced technologies and reserving a group of professionals for the study of the lunar samples returned by Chang ‘e-5.For example, the “Ion probe ultra-high spatial resolution dating” technology took us more than 10 years to reduce the spatial resolution from 20 microns to 10 microns and then to 5 microns. Finally, last year, we achieved a high precision dating of about 3 microns, and the Chang ‘e-5 sample is just 3 microns in size.Many young researchers born in the 1980s and 1990s in our team have been preparing for the same thing since they entered the institute. They have been doing the same thing for more than 10 years with a sense of sacred mission. They are really “sharpening one sword after 10 years”.Shortly before chang ‘e-5 returned with the samples, we did a lot of organizing and coordination work, including a drill with the Apollo samples, to make sure there were no problems in coordination.Acta Scientia Sinica: What new insights have you gained from these studies?Yang Wei: In the three papers we published in Nature, we came to conclusions about three scientific questions.In the first article on the moon’s “death age,” we pushed back the exact date of the cessation of lunar magmatic activity from 2.8 to 3 billion years ago to 2 billion years ago, thus extending the moon’s “life” to 2 billion years ago.In the second article, on the source of heat from magmatic activity, we found that the source of heat for lunar magmatic activity was not the “warm baby” of radioactive elements that we had previously thought.In the third, about water, we found that the basalt sampled by Chang ‘e-5 actually came from a very dry lunar mantle.Of course, all this work is just a starting point, and we have just received our third batch of Chang ‘e-5 samples, creating a long list of future studies to follow.I will act soon, and I will certainly not rest during the Spring Festival. I believe that the “high combustion” will continue and more conclusions will be obtained.Acta Scientia Sinica: People are also concerned about whether vegetables can grow on the moon.Yang Wei: This is a very down-to-earth question.The moon doesn’t look like a good place to grow vegetables — no liquid water, no organic matter, no microbes.Although we measured water in the lunar samples, that was inferred by measuring hydrogen atoms in the rocks, which turn into water when heated and oxidized.However, lunar soil, as a basalt weathering product, has the priori conditions to become soil.The rich black soil of the earth is formed by weathering of basalt.If one day put the “soil” on the moon on the earth, add oxygen and water, to transform it, I believe it is completely possible to grow vegetables.(Gan Xiao) Source: Journal of Integrated Science of Guangming Network