Asteroid impact is one of the potential disasters facing human civilization in the future. About 200 large impact events have been recorded on Earth, and asteroid impacts thousands of meters in diameter are enough to cause mass extinctions. The impact flux has declined exponentially since the Earth was formed 4.5 billion years ago. So, has the impact frequency of asteroids in the Earth-Moon system attenuated steadily? Could a large number of near-Earth asteroids lead to a sudden increase in future impact events? The lunar soil samples returned by Chang’e 5 are the best research objects to find relevant answers. An international research team composed of Chinese and foreign scholars has confirmed that the frequency of impacts on the moon has changed over time over the past 2 billion years by correlating glass spherulites in the lunar soil with nearby impact craters. The study was published in the journal Science Advances. It is worth noting that the age of the impacted glass spheroids in the Chang’e-5 lunar soil is the same as that of several groups of impact events in the asteroid belt. One of the ages is consistent with the dinosaur extinction event, representing a sudden increase in the frequency of impacts at that time.
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