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Where do shooting stars come from? It’s long been known that meteors are caused by meteorites striking Earth’s atmosphere, but their origin has puzzled scientists since ancient times. About 70,000 meteorites have been found on Earth. New research identifying the origin of more than 90% of them has revealed that 70% come from just three groups of asteroids, all of them relatively young.
Of the 10% of meteorites without a known source, 6% come from the moon, Mars or Vesta, the latter one of the largest objects in the main asteroid belt between Mars and Jupiter. Meteor Showers All meteor showers — the most famous being the Perseids in August — result from dust and debris left in the solar system, typically by a comet. For example, during the famous Perseid meteor shower, it’s comet Swift–Tuttle, whose detritus strikes Earth’s atmosphere on Aug.
12-13 each year. For the Geminids on Dec. 13-14, it’s an asteroid called 3200 Phaethon.
However, shooting stars occur every night when Earth busts into a meteorite in space. Asteroid Families The research pinpoints 70% of them as originating in three young asteroid families — called Karin, Koronis and Massalia — that were formed by collisions in the asteroid belt about 5.8, 7.
5 and 40 million years ago, respectively. Young families of asteroids contain a lot of small fragments left over from collisions. Most of the meteorites are regular chondrites, stony, non-metallic objects of iron, magnesium, silicon and oxygen.
Detailed Survey According to the research, the Massalia family of asteroids is the source of 37% of known meteorites, which comes from three papers, one published in Astronomy and Astrophysics in September and two published ( here and here ) in Nature in October. The research included a detailed survey of all the major asteroid families in the main belt, with computer simulations revealing how each major family of asteroids has collided and evolved. ‘Planet-Killer’ Asteroids The researchers also discovered the origin and evolution of some of the biggest objects in the main asteroid belt, including kilometer-sized asteroids that could threaten Earth.
It was confirmed that “planet killer” asteroids Ryugu and Bennu, which were recently sampled by Japan’s JAXA’s Hayabusa2 and NASA’s OSIRIS-REx missions, respectively, come from the same group of asteroids in the inner main asteroid belt. Wishing you clear skies and wide eyes..
