In 1969, over the Australian village of Murchison, a 100-kilogram meteorite exploded, its particles scattering over several kilometers.
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Scientists obtained about 52 kg of it.
[8d88]. , and in the 1990s microscopic particles of silicon carbide were found inside it.
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These were presolar grains, but researchers were not able to calculate their exact age.
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Recently they were able to do this.
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The researchers crushed pieces of the meteorite into powder, and dissolved it in acid.
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Insoluble particles of silicon carbide up to eight micrometers in size remained - presolar grains.
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There were 40 of them.
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After studying data on the interaction of grains with cosmic rays, scientists found that they were formed between 5 and 7 billion years ago.
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When interacting with these rays, new elements are formed, and the longer the grains are exposed, the more of these elements are formed in them.
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Most presolar grains were between 4.6 and 4.9 billion years old, but some were as old as 5.5 billion years.
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This suggests that a period of active star formation occurred in our galaxy five to seven billion years ago.
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According to scientists, the materials found are currently the only evidence available to humanity about the existence of the period preceding the emergence of the Sun and Earth.
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The discovery of a group of scientists from the USA, Switzerland and Australia was reported in Proceedings of the National Academy of Sciences.
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It is also interesting to note that Japanese and American astrobiologists discovered traces of complex sugars in two celestial bodies: in the Moroccan meteorite NWA 801, and in the Murchison meteorite.
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In both objects, molecules of pentose sugars were found, which contain five carbon atoms and hexoses.
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This discovery suggests that asteroids played the role of the main source of organic matter for the early Earth.
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Warning: these questons and answers are not all representative of the way questions will be asked and answered in the pilot, because some questions are compound and some answers do not include citations.

Q: When did a meteorite explode over the Australian village of Murchison?
A: In 1969

Q: How much did the Murchison meteorite weigh?
A: 100 kilograms

Q: How far did the particles of the Murchison meteorite scatter?
A: Over several kilometers

Q: How much of the Murchison meteorite did scientists obtain?
A: About 52 kg 

Q: What mineral was found inside the pieces of the Murchison meteorite in the 1990s?
A: Silicon carbide

Q: What were the microscopic particles of silicon carbide found inside the pieces of the Murchison meteorite in the 1990s?
A: They were presolar grains 

Q: What have researchers recently been able to do to presolar grains found inside the pieces of the Murchison meteorite in the 1990s?
A: Calculate their exact age 

Q: What did the researchers first do to calculate the exact age of presolar grains?
A: They crushed pieces of the meteorite into powder, and dissolved it in acidA: They crushed pieces of the meteorite into powderA: They dissolved crushed pieces of the meteorite in acid

Q: How many presolar grains did researchers manage to obtain to calculate their age?
A: 40

Q: What method did researchers use to calculate the age of presolar grains?
A: They studied interaction of presolar grains with cosmic rays

Q: What happens when presolar grains interact with cosmic rays?
A: New elements are formed

Q: How old were most presolar grains?
A: Between 4.6 and 4.9 billion years old

Q: How old were the oldest of presolar grains?
A: 5.5 billion years

Q: What suggestion did scientists make about a period of active star formation in our galaxy after calculating the age of presolar grains?
A: That it occurred five to seven billion years ago

Q: What country were the scientists who calculated the age of presolar grains from?
A: The USA 

Q: What country were the scientists who calculated the age of presolar grains from?
A: Switzerland 

Q: What country were the scientists who calculated the age of presolar grains from?
A: Australia

Q: What journal was the discovery of the age of presolar grains reported in?
A: Proceedings of the National Academy of Sciences

Q: What organic substance did Japanese and American astrobiologists discover in the Murchison meteorite?
A: Complex sugars

Q: What did the discovery of complex sugars in the Murchison meteorite suggest?
A: That asteroids played the role of the main source of organic matter for the early Earth