Can you find cosmic dust on the roof?

Since ancient times, the sun, moon and stars in the sky have attracted the attention of human beings. In order to explore the secrets of the universe, humans use various tools to observe the stars. To date, humans have launched more than 200 detectors into the deep space of the solar system. In addition to human beings actively exploring space, there are also a large number of “alien messengers” coming to Earth: big to comets and asteroids, small to the inconspicuous cosmic dust.

On February 15, 2013, a 18-meter-diameter asteroid entered the Earth’s atmosphere and exploded in Chelyabinsk, a small town in Siberia, Russia, causing thousands of injuries and numerous building damage. If the asteroid has a larger diameter, such as a diameter of 60 meters, and there is no explosion in the air, it can destroy a larger city. If the diameter of an asteroid reaches 10 kilometers, it can even lead to the disappearance of human beings from the earth. The tyrannosage of the earth, 65 million years ago, is very likely to be extinct. According to the statistics of paleontological fossils in the strata, on average, every 26 million years, there will be a mass extinction on the earth. We have not encountered such a crisis, only because of the history of human existence on the earth. It’s too short.

Compared with these powerful big guys, there are tens of thousands of tons of cosmic dust (mainly the emblem stone) that land quietly on Earth every year. These dust particles are less than 1 mm in diameter, from the uninhabited north and south poles to the bustling metropolis, where about 100 tons per day land on Earth.

The scientific community has a long history of research on micrometeorites. The earliest pioneers were John Murray and Adolf Erik Nordenski?ld, followed by Lucien Rudaux and Harvey H. Nininger. Special mention is made here of the contributions of Donald E. Brownlee and Michel Maurette. It is because of their efforts that micrometeorite research has become a The real subject of the door.

In the past 20 years, research on searching for cosmic dust has progressed very rapidly. Scientists have found a large number of micrometeorites in areas where the air is clean and inaccessible, especially in the Antarctic, which has accumulated tens of millions of years of ice and snow. In an Antarctic well that provided drinking water for the Antarctic scientific research station, Susan Taylor invented a good way to extract micrometeorites and collected a lot of micro-fine particles. Another scientist, Matthew Genge, established a method for classifying micrometeorites. Since the first hand research sample, there have been more and more research papers on micrometeorites.

Although in prehistoric sediments before human production, as well as in deserts, Gobi and glaciers far from human smoke, there are many micrometeorites in theory because they are not significantly affected by human activities. However, the micrometeorites previously discovered are mainly from the Antarctic.

So, can you find micrometeorites in densely populated areas? Previously, experts in this field have always believed that this is impossible, because in densely populated areas, pollution is inevitable, and numerous artificial and natural particles originating from the earth will inundate relatively small quantities of micro. Meteorite.

Jon Larsen is a famous Norwegian pop musician whose band has promoted the global recovery of Gypsy Jazz. At the same time, he was an avid rock specimen collector since childhood. Beginning in 2009, he collected dust samples from densely populated areas and systematically studied dust samples from these areas in an attempt to find micrometeorites from space.

But because you don’t know what the micrometeorites look like, it’s impossible to find them. The search results are frustrating. Jon Larsen realized that it is not feasible to look for micro-meteorites. It is necessary to identify 10 artificial and natural particles originating from the Earth at the same time. Find the difference between micrometeorites and other particles in order to screen out micrometeorites.

Initially, he only looked for on the hard ground, such as roads, roofs, parking lots and industrial areas, because of the accumulation of dust particles in these places. Later, he went to other countries and cities, mountains, beaches, deserts and other places to find. In the past 6 years, he has traveled to nearly 50 countries, conducted thousands of searches, and visited every continent in the world. He used a ZEISS binocular microscope to observe all the collected samples, picked out the interesting particles, took pictures with a microscope, and archived them. He took more than 40,000 photos, one for each particle.

Hard work pays off, and interest is the best mentor to success. In 2015, Jon Larsen finally found the first micrometeorite, and Matthew Genge, a planetary scientist at Imperial College London in London, confirmed the discovery. Very Shaanxi, he found more than 500 similar micrometeorites.

In the book “Looking for Cosmic Dust on the Roof,” Jon Larson reports on his microscopic meteorite empirical studies in densely populated areas, showing many micrometeorites and a large number of artificial and natural particles derived from the Earth. Microphotographs and systematic analysis of these small spheres.

When I saw this book, I was shocked by the high-definition big picture of the tiny particles in the book. These particles, which are a few millimeters or less in diameter, are magnified by the microscope to a few centimeters or even a dozen centimeters, and the rich surface details are revealed, reflecting their simple or complex life. In addition to micrometeorites, these tiny particles come from factory cutting machines, electric welders, grinding wheels, mold workshops, some brake pads from cars, asphalt pavement dust, some from kitchen smoke, lighter ignition, holiday fireworks, Others come from sandstorms, volcanic eruptions, lightning, and even animal and plant residues, microbial remains on the beach.

Micrometeorites are the oldest substances in the world. They are the remains of the solar system planets. They contain stardust that is older than the sun and dust particles that are farther away than anything else on Earth. Mineralization and geochemistry of micrometeorites by means of high-precision and modern analytical methods such as scanning electron microscopy, electron probe microanalyzers and nano-ion probes can reveal their formation and evolution history, the origin of the solar system and Evolution, the origin and evolution of planets, and even the origin of life, provide more physical samples.

Because the cosmic dust not only has particles after the formation of the solar system, but also particles before the formation of the solar system. Not only particles from the solar system, but even particles from the solar system. Therefore, by studying the dust of the universe, we can significantly enhance our understanding of the solar system and even the entire universe and even the origin of life. Seeing the micro-intelligence, paying attention to these cosmic dusts is actually concerned with the fate of human beings.

In China, the study of meteorites and cosmic dust began in the 1960s and 1970s. The research institute of the Institute of Geochemistry of the Institute of Geochemistry of the Chinese Academy of Sciences in Guiyang has this research team. Ouyang Ziyuan, the chief scientist of China’s first lunar exploration project, and academician of the Chinese Academy of Sciences, and his colleagues and students have long been engaged in research on the moon and meteorites. In a sense, it is the study of various meteorites and lunar rocks that laid the scientific foundation for the later lunar exploration project.

More than 10 years ago, when I was a graduate student, I worked on the identification of pollen and spores in the Nanjing Geological Paleontology Research Institute of the Chinese Academy of Sciences. We extracted the pollen and spores of ancient plants from the soils of different ages and identified which plants they came from. Based on the combination of these plant species, we can speculate whether the ecological environment at that time was warm and humid, or cold and dry. When I was doing pollen and spore identification, I had a handbook on hand for us to compare. According to the high-resolution photos on the manual, I identified the plants under which the pollen and spores belonged.

Nowadays, the collection of meteorites is popular in the society, but there are many mixed fishes and fakes. Many people have been deceived and paid a heavy price. At present, domestic players are still keen on collecting large pieces of meteorites, but the international has already begun to raise the micro-stone collection, this wind will soon be scraped into the country. For the micrometeorite collection, if there is a manual, showing micro-meteorites and various artificial and natural particles originating from the earth, naturally it can reduce many opportunities for deception.

We used to think that the universe is far away from us. But among the tiny particles that we can see around us, in every breath we breathe, in the dust that falls on our desks, in every bite we eat, there may be cosmic dust from space. .

These tiny particles are messengers from the universe. They are reminding humans that we are always in exchange with the universe.