Meteorite weather damage is reduced

1909 65438+1In mid-October, a group of people walked 1000 kilometers in the cold and dangerous crevice with dozens of kilograms of materials. Due to the limited conditions, the vehicle can't be used, so we have to go forward, determined to find the magnetic south pole of the earth. In the decades after the expedition led by Ernest shackleton discovered the South Magnetic Pole, many scientists flocked here to make silent contributions to the scientific cause.

More than a century has passed, and scientific research in Antarctica is still facing great challenges. Although the conditions here are bad, its scientific research value is still relatively large. For example, every year, scientists come here to collect meteorite fragments that fell in Antarctica, because these meteorites record the information about the origin of the earth and the solar system.

1969, a Japanese glaciologist working in the Antarctic discovered seven meteorites. Through testing, he found that these meteorites came from different meteors and started the Antarctic meteorite project. Seven years later, Japanese and American researchers organized a joint search mission, which quickly became an annual activity. In the following 40 years, scientists collected more than 23,000 meteorites from Antarctica.

As the coldest and driest place on earth, Antarctica has formed a natural freezer, which can well preserve meteorites. Once the meteorite is frozen into ice, the movement of the glacier will take it from the pole to the coast, which is like a natural conveyor belt. Every year in June 5438+065438+ 10, a few scientists go to the plateau in the south of the Antarctic mountains and spend about six weeks collecting meteorites. However, six weeks from 1/4 to 1/3 are not suitable for work, mainly because of the weather. Sometimes some astronauts will join the research team, because the lonely environment in Antarctica can be used as part of the psychological training of the International Space Station.

In the past few weeks, scientists have collected hundreds of meteorites of different sizes, most of which are fist-sized and a few are about the size of a football. In the process of collection, it is very important to correctly identify meteorites. When these "whispers" pass through the atmosphere, the outside becomes hot and begins to melt due to friction. If it is not completely melted, a layer of molten shell (thin and black coating, called molten shell) will be formed outside it, which is an important basis for identification.

Scientists will collect meteorites, freeze them and transport them to the space center in Texas. The researchers in the Space Center thawed them again, then broke them into small pieces and sent them to the laboratory for chemical analysis. After that, meteorites will be classified and stored in museums. In order to prevent rust, weathering or mineral leaching, meteorites will be placed in a box filled with nitrogen.

Meteorites in Antarctica don't contain organic matter like meteorites landed in other places, so they provide unpolluted first-hand information for the formation of our solar system. Most meteorites from the asteroid belt can be traced back to 4.6 billion years ago, so if we want to know the first 5 billion years of the solar system history, then meteorite fragments are the best way.

Geologists believe that more than 99% of meteorites in the Antarctic collection area come from the asteroid belt, while the proportion of meteorites from the moon and Mars is less than 1%. Most of them are chondrites (nonmetallic meteorites composed of small particles, called chondrites). And some meteorites contain mineral fragments before the formation of the solar system. These mineral fragments are also called "pre-solar particles". Scientists think they come from a star. When our solar nebula was just formed, this star just exploded nearby. There are also a few chondrites called carbonaceous chondrites, which are considered to be related to the formation of the oceans on earth.

Around Antarctic meteorites, scientists will launch a series of scientific research tasks in the next few years, including finding the types of meteorites containing water-bearing minerals that produce oceans and lead to life on earth, and studying how planets form iron cores. The collection of Antarctic meteorites inspired and guided these new space missions. I believe that scientists will have a new understanding and cognition of the early solar system after studying each new meteorite. The content of this issue will come to an end. Let's meet in the comment area, exchange views and learn from each other.