WASHINGTON : Meteorites – rocks that fall to Earth from space – have pelted our planet from its birth about 4.5 billion years ago to today, often causing scant damage but sometimes triggering cataclysms. But from where exactly are these space rocks coming? New research has the answer.
By studying the composition of meteorites that have landed over the years and the asteroids populating our solar system, astronomers have determined that about 70 per cent of known meteorite impacts came from just three groups of asteroids residing in our solar system’s main asteroid belt between Mars and Jupiter.
In total, the researchers in three different studies have now been able to account for the origins of most of the tens of thousands of known meteorites that have landed on Earth.
As part of the research, the astronomers carried out numerical simulations that enabled them to model the formation and evolution of families of asteroids orbiting the sun in the main asteroid belt.
“It is a group of asteroids which have similar orbits because they were fragments created during a collision between two asteroids,” said astronomer Miroslav Brož of Charles University in Prague, lead author of two of the studies, published in the journal Nature and Astronomy and Astrophysics.
Collisions in the main asteroid belt send rocky fragments flying haphazardly through space, with some of those eventually striking Earth.
“While more than 70,000 meteorites are known, only 6 per cent had been clearly identified by their composition as coming from the moon, Mars, or Vesta, one of the largest asteroids in the main asteroid belt. The source of the other meteorites had remained unidentified,” said astronomer Michaël Marsset of the European Southern Observatory in Chile, lead author of one of the two studies published in the journal Nature.
The Massalia asteroid family, formed about 40 million