The Asteroid Belt lies between Mars and Jupiter, and is home to more than a million space rocks at least 1 km in diameter. For the study, the team analyzed all families of large asteroids in the Belt, observing them in detail. Then, they used the information to create simulations, reconstructing the formation of the objects and identifying when the collisions that gave rise to them occurred.
In the end, they concluded that many of the meteorites came from just three families. Karin, one of the youngest, was formed 5.8 million years ago and has at least 90 known asteroids; The Koronis family was created 7.5 million years ago and has more than 5,900 objects — Ida is one of them, and was the target of NASA's Galileo mission.
Finally, the oldest family of objects is Massalia, created 40 million years ago. There are more than 6 thousand asteroids, which are responsible for more than 37% of meteorites. Now that the origin of the meteorites has been determined, another mystery remains to be solved: why did so many come from just three collisions?
According to the team, the secret lies in the asteroid families themselves, where impacts are much more likely to happen. As asteroids have similar orbital properties, they are all relatively grouped together, that is, they are more likely to collide with each other. These impacts create new rocky fragments — sometimes, some are fired across the Solar System, and end up colliding with Earth.
Michaël Marsset, lead author of one of the studies published on the discovery, explained that the most recent collisions occurring in the Belt are completely dominating the flow of materials towards our planet. “You might think that the stream of meteorites should be a mixture of all the compositional classes seen in the Belt, but that is not the case, it is dominated by three asteroids that recently broke up,” he told Gizmodo.
The Asteroid Belt lies between Mars and Jupiter, and is home to more than a million space rocks at least 1 km in diameter. For the study, the team analyzed all families of large asteroids in the Belt, observing them in detail. Then, they used the information to create simulations, reconstructing the formation of the objects and identifying when the collisions that gave rise to them occurred.
In the end, they concluded that many of the meteorites came from just three families. Karin, one of the youngest, was formed 5.8 million years ago and has at least 90 known asteroids; The Koronis family was created 7.5 million years ago and has more than 5,900 objects — Ida is one of them, and was the target of NASA's Galileo mission.
Finally, the oldest family of objects is Massalia, created 40 million years ago. There are more than 6 thousand asteroids, which are responsible for more than 37% of meteorites. Now that the origin of the meteorites has been determined, another mystery remains to be solved: why did so many come from just three collisions?
According to the team, the secret lies in the asteroid families themselves, where impacts are much more likely to happen. As asteroids have similar orbital properties, they are all relatively grouped together, that is, they are more likely to collide with each other. These impacts create new rocky fragments — sometimes, some are fired across the Solar System, and end up colliding with Earth.
Michaël Marsset, lead author of one of the studies published on the discovery, explained that the most recent collisions occurring in the Belt are completely dominating the flow of materials towards our planet. “You might think that the stream of meteorites should be a mixture of all the compositional classes seen in the Belt, but that is not the case, it is dominated by three asteroids that recently broke up,” he told Gizmodo.