Moon asteroid impacts provide a window into the Earth's ancient past
The moon is thought to mirror the Earth's ancient past in several ways. The giant-impact hypothesis, for example, states that the moon was once part of the Earth before a massive collision caused it to separate.
Then there are the finely preserved craters that reveal a great deal about the violent periods in Earth's ancient past when many more asteroids rained down on both the moon and the Earth.
A team of researchers recently studied lunar glass samples leading them to discover that asteroid impacts on the moon millions of years ago accurately coincide with some well-known large meteorite impacts on Earth — including the one that killed off the dinosaurs.
Their study shed new light on the Earth's ancient past while revealing unique insight into major historic collision events.
Chang'e-5's lunar glass bead samples
The international research team analyzed microscopic glass beads as old as two billion years old. These were found in lunar soil collected and brought to Earth by the Chinese National Space Agency’s Chang'e-5 Lunar mission in December 2020. The glass beads were created by the heat and pressure of ancient meteorite impacts, which provides valuable information about when the impacts took place.
In a paper published in the journal Science Advances, the scientists outlined the methods they used to analyze the lunar beads. They also highlighted the discovery that major impact events on Earth were likely often followed by a series of smaller impacts.
Their study of impacts on the moon revealed new information related to asteroid dynamics in the inner solar system. It also shed new light on the probability of massive, hazardous Earth-bound asteroids.
According to the lead author of the study, Professor Alexander Nemchin, from Curtin University’s Space Science and Technology Centre (SSTC), their analysis suggests the timing and frequency of asteroid impacts on the moon mirror historic impacts known to have occurred on Earth. That means their findings tell us more about the evolution and history of our planet.
Analyzing the moon and Earth's ancient past
The team used several microscopic analytical techniques alongside numerical modeling and geological surveys to ascertain how the lunar glass beads were formed and when.
"We found that some of the age groups of the lunar glass beads coincide precisely with the ages of some of the largest terrestrial impact crater events, including the Chicxulub impact crater responsible for the dinosaur extinction event," Professor Nemchin explained.
The researchers also found that the Chicxulub impact 66 million years ago may have been accompanied by a series of smaller impact events. "If this is correct," Professor Nemchin said, "it suggests that the age-frequency distributions of impacts on the Moon might provide valuable information about the impacts on the Earth or inner solar system.”
According to the scientists, the next step is to compare their data with other lunar soil samples and crater ages. As per the team's new findings, the more we discover about the moon, the more we will know about our own ancient history — and extinction events that took place in eons past.
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