Earth is continuously bombarded by meteorites, with many burning up in our atmosphere before reaching the surface. Significant impacts can occur, leading to potential consequences for life on our planet. It has established with research that the majority of meteorites that land on Earth originate from the asteroid belt, a region located between Mars and Jupiter. This area is populated by irregularly shaped rocks that are remnants of the solar system’s formation. Recent studies have revealed new insights into the specific sources of these meteorites.
Identification of Asteroid Families
A recent study conducted by an international team of scientists suggests that three distinct asteroid families in the main asteroid belt account for approximately 70 percent of the meteorites found on Earth. These families, the Karin, Koronis, and Massalia families, were formed from collisions in the asteroid belt that occurred approximately 5.8 million, 7.5 million, and 40 million years ago, respectively. The Massalia family is estimated to be responsible for 37 percent of all known meteorites.
Methodology of Research
They employed a telescopic survey to analyse the composition of the major asteroid families in the belt. They also used computer simulations to understand the dynamics and evolution of these families over time. Previously, only 6% of meteorites had been definitively linked to celestial bodies such as the Moon, Mars, or Vesta, one of the largest objects in the asteroid belt. The origins of the remaining 94% had been less clear.
Why Younger Families Contribute More Meteorites
The prominence of these younger asteroid families as sources of meteorites can be attributed to their composition. Younger families, having formed from relatively recent collisions, consist of more fragments. This abundance of fragments increases the likelihood that some will escape the main asteroid belt and eventually collide with Earth. Over time, older asteroid families tend to lose their fragments, making them less likely to contribute to meteorite falls.