In 2013, the Chelyabinsk meteor exploded in Russian skies so violently that around 1,500 people sought medical attention, mostly because of broken glass from the crash.
At the time, a series of videos of the impact of this small asteroid 17m in diameter in our atmosphere went viral in the social networks. Yet scientists claim that only a fraction of the thousands of meteorites (fragments left on the ground) had been found.
But the explosion that caused such a stir may not have been the space rock’s first visit to Earth.
According to the researchers, a rock the size of Mars would have collided with the Earth during the formation of the Solar System, 4.5 billion years ago, releasing fragments. And it was precisely this ejected material that came together and formed the Moon as we know it.
This is revealed by a study published in the scientific journal Nature, one of the most prestigious in the world.
A study by researchers at the University of Cambridge, UK, used a new mineral analysis method to establish dates linked to the collisions of space rocks – like asteroids and comets – during formation of the solar system.
With this, they discovered that the asteroid that caused the meteor of Chelyabinsk had suffered two impacts, one about 4.5 billion years ago and the other about 50 million years ago.
We know that during its formation, zircon (zirconium ore) rejects lead but incorporates uranium. This means that any lead found in zircon is related to the radioactive decay of uranium. Because scientists know how long uranium takes to decay, they can calculate the age of zircon from the lead component.
This should help trace the history of planets, like Earth, from the very beginning – one of the biggest challenges for astronomers.
Meteorites function as a time capsule allowing scientists to return to the origins of the solar system, as they have undergone virtually no chemical change while floating in space.
Thus, by analyzing the minerals found in meteorites that have fallen to Earth – such as those from Chelyabinsk – it is possible to reconstruct these ancient collisions.
In the new study, experts found, for example, that an earlier impact had blasted the larger asteroid into pieces, subjecting them to extremely high temperatures. The latest event generated lower pressure and temperatures, indicating that it must have occurred at least 50 million years ago.
this second impact who would have separated the meteoroid in Chelyabinsk of the larger body and the one sent on a collision course with Earth.
“Ages are often controversial. Our work shows that we need to rely on multiple sources of evidence to be more certain of impact stories – almost like investigating an old crime scene,” said geoscientist Craig Walton of the Cambridge University. all of these asteroids are experiencing intense melting at this time may indicate the reorganization of the solar system, resulting from Earth-Moon formation or perhaps from the orbital movements of the giant planets.”
Now researchers need to revisit the timing of the Moon’s formation to try to shed some light on this theory.