(ORDO NEWS) — Microscopic glass shards from the Moon have revealed a history of lunar impacts that exactly matches meteorite impacts on Earth including a giant asteroid impact 66 million years ago that killed most life and wiped out the dinosaurs.
Using a series of methods, the team of scientists accurately tracked the 135 tiny glass beads brought to Earth for the China National Space Agency’s Chang’e-5 sample return mission back to their formation.
“We found that some of the age groups of the lunar glass beads match exactly those of some of Earth’s largest impact craters, including the Chicxulub impact crater responsible for the extinction of the dinosaurs,” said geologist Alexander Nemchin of Curtin University in Australia.
The study also suggests that large Earth impacts, such as the Chicxulub asteroid that ended the reign of the dinosaurs, may have been accompanied by several smaller impacts.
“If our assumptions are correct, then it can be assumed that the frequency distribution of collisions with the Moon can provide valuable information about a collision with the Earth or the inner solar system,” the scientist said.
What happens when an asteroid collides with a planet
An asteroid or meteorite impact can be an extremely energetic event, often releasing large amounts of heat.
If silicate material is present in the rock and both the Earth and the Moon have it this heat can cause melting and transformation, which later show up as tiny glass spheres called “impact balls.”
In addition to silicates, there are many other types of materials on the Moon, and sometimes these other materials can bind in impact balls in large enough quantities for us to analyze them.
This means that if scientists get their hands on some of these marbles, they can study them to learn more about how, when and in what environment they formed.
The Chang’e-5 lunar sample return mission provided an opportunity to carry out such a study.
What did the moon glass say
A team led by geologist Tao Long of the Chinese Academy of Geological Sciences in Beijing isolated 215 beads ranging in size from 50 to 200 micrometers from a piece of soil collected by Chang’e-5 and began analyzing them.
Some marbles did not contain enough additional material for detailed study. On the remaining 135, the researchers ran various tests to get the chemical composition and lead-uranium to determine their age.
This is a method based on the radioactive decay of uranium into lead. Since we know how long it takes for uranium to decay, the relative amounts of uranium and lead in a sample can give us an estimate of the age of the sample.
The results show that the marbles were mostly of local origin, from the area around the Chang’e-5 lander. However, modeling suggests that they can be thrown about 100 kilometers from the impact site.
Simulations also suggest that the spherules were also formed mainly by impacts that left craters ranging in diameter from 100 to 1,300 meters. This information allowed the team to tentatively identify craters in the region where they may have formed.
How long ago did this happen?
The age of the balls ranged from a few million to 2 billion years – this upper limit was when the basin in which the Chang’e-5 landed was covered with fresh volcanic basalt.
Of particular interest were balls aged 68 and 34 million years ago. The first coincides with the Chicxulub event; the latter with few Late Eocene craters.
While this could be a coincidence, parallel time suggests that the point of origin of these events perhaps a collision in the asteroid belt could have formed many rocks that hit the Earth and the Moon at the same time.
This may give us new insights into how these impactors form and develop, as well as the dynamic processes in the asteroid belt.
“The next step is to compare the data obtained from these Chang’e-5 samples with other lunar soils and crater ages to be able to identify other important impact events on the entire Moon.
In turn, this could open up new data about what impacts could have affected life on Earth, ”said planetary scientist Katarina Milkovich from Curtin University.
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