Scientists have long thought that meteorites, those chunks of asteroids that collide with the Earth’s surface, have emanated from different space rocks located in the asteroid belt, a circumstellar disk of the solar system located between the orbits of Mars and Mars. Jupiter. However, contrary to current theories, a new study conducted at the University of Lund (Sweden) of the meteor shower from space on our planet during the last 500 million years has shown that only 1 of the 70 Larger collisions that took place in the asteroid belt caused a major increase in the flow of meteorites towards Earth.
Where do meteorites come from?
Knowing it could help to understand what kinds of objects can collide with the Earth and where they come from, since following the history of the Earth’s meteorites is not an easy task. Impact events involving large bodies leaving a significant crater are rare; Typically, many space rocks break apart upon entering the atmosphere, leaving only debris that falls to Earth. These debris are small fragments of micrometeorite, preserved in the sedimentary layers of the earth’s crust.
To elucidate the mystery, researchers at the Astrogeobiology Laboratory dissolved nearly ten tons of sedimentary rocks from ancient sea beds in powerful acids, because the sediment contains residues of meteorites dating from when they fell to Earth.
“The dissolved sediment represents 15 periods during the last 500 million years . In total, we have extracted chromium oxide from almost 10,000 different meteorites. Chemical analysis allowed us to determine what types of meteorites the grains represent,” says geologist Birger Schmitz.
Thus, most of the meteorites that reach Earth could be from the same parent body. Scientists believe that the meteorites that have fallen on Earth so far can be traced back to major asteroid events that broke off in space, leading to a meteorite cascade crash landing on our planet.
According to NASA, more than 1 million asteroids are known to exist. Space rocks originate in the asteroid belt between Mars and Jupiter, where celestial bodies hit by giant collisions revolve around the Sun. But the results of the study suggest that asteroids leaving the asteroid belt between Mars and Jupiter appear to come from a very small region.
“We were very surprised to learn that only one of the 70 largest asteroid collisions that took place during the last 500 million years resulted in an increased flow of meteorites to Earth. For some reason, most of the rocks remain in the earth. asteroid belt “, clarifies Schmitz.
What is the reason? Experts do not know.
Understanding the origins of meteorites can not only help us better understand how the solar system formed, but also which space rocks could endanger humanity in the future, the authors say.
Referencia: Fredrik Terfelt et al, Asteroid break-ups and meteorite delivery to Earth the past 500 million years, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2020977118
