In 1969, over the Australian village of Murchison, scientists observed a very unusual phenomenon. It was then that a 100-kilogram meteorite exploded in the sky, the particles of which were scattered over a radius of several kilometers. Scientists managed to get hold of about 52 kilograms of the space object and in the 1990s microscopic particles of a mineral called silicon carbide were found inside it. The researchers suggested that they are dealing with the so-called pre-solar grains - interstellar matter that formed long before the appearance of the Sun and Earth. In those days, they did not have the opportunity to calculate the exact age of the materials found, but recently they finally managed to do this. As scientists expected, they were dealing with the most ancient materials ever to appear on our planet.
The discovery of a group of scientists from the United States, Switzerland and Australia was reported in a scientific publication called Proceedings of the National Academy of Sciences. By grinding the found samples of the Murchison meteorite, the researchers managed to extract 40 particles of pre-solar grains. Determining their age turned out to be a very difficult task, but scientists did it using data on the time of exposure to cosmic rays. This term is commonly understood as streams of high-energy particles that fly through our entire galaxy and penetrate into solids. It is known that when interacting with these rays, new elements are formed in pre-solar grains, and the longer the interaction takes place, the more of these substances are ultimately observed.
Oldest material on earth
Having studied the data on the interaction of grains with cosmic rays, scientists have found that they were formed between 5 and 7 billion years ago. Based on the fact that our solar system was formed 4.6 billion years ago, it turns out that the particles found by scientists were formed long before the appearance of the sun. According to scientists, the materials found at the moment are the only evidence available to mankind about the existence of a period preceding the emergence of the Sun and the Earth.
In general, such materials can be found inside many meteorites that have fallen on our planet. Only now it is extremely difficult to detect and recognize them, because they are embedded deeply into space objects and are microscopic in size. The fact that scientists were able to extract them from the Murchison meteorite is a great success. Through the study of these particles, scientists can make various assumptions about the evolution of the universe and tell a lot of interesting things about how our planet was formed.
Fragment of the Murchison meteorite in the museum.
You can also read about the Murchison meteorite in our material about whether the Earth could have formed with life already existing on it. After all, who knows - perhaps our planet was originally inhabited by living beings and we simply do not know about it?
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Ramis Ganiev