Experts from Prague’s Charles University, in cooperation with scientists from France, the USA and the European Southern Observatory, have discovered the origin of 70% of meteorites that hit the Earth, which are three asteroid families, according to an online announcement from the university’s Faculty of Mathematics and Physics.
Computer models by scientists at the faculty’s Institute of Astronomy have shown that the most prolific source of meteorites are the asteroid families named Massalia, Koronis and Karin. Meteoroids, some of which then hit the Earth as meteorites, are formed by collisions between asteroids orbiting the Sun that took place tens of millions of years ago. Two studies on the origin of meteorites were published in mid-October by the prestigious scientific journal Nature.
The meteoritic material formed from dust long before the Earth came to being, just two million years after the Sun’s formation 4.567 billion years ago, said the scientists, citing radiometric measurements of meteorites. The material formed asteroids, around 10 kilometres in length, which collide and fragment once every few million years when their orbits around the sun cross, producing meteoroids, which then orbit the sun independently.
“Now, Czech researchers have succeeded in creating the most complete model to date describing the dynamics of asteroids in the main belt and near the Earth, as well as the origin of meteoroids of different types,” said the faculty website.
Asteroids break up into fragments when they collide with each other. The first fragmentation took place about 40 million years ago, the second about 7.6 million years ago and the third about 5.8 million years ago, said Miroslav Broz from the Faculty of Mathematics and Physics.
The source of the meteorites hitting the Earth are mainly the aforementioned asteroid families Massalia, Koronis and Karin. “Together, 70% of all meteorites have been explained in this way. These are the same types of meteorites that were observed by the predecessors of man,” the Czech scientists said.
Their calculations were preceded by the work of astronomers Michael Marsset from the European Southern Observatory and Pierre Vernazza from the University of Aix-Marseille in France. They used spectroscopy in the telescope to classify asteroids according to the minerals they contain, similar as is done with meteorites. Researchers from the Massachusetts Institute of Technology (MIT) in the US and several other institutions also contributed to the two studies published in Nature.
