Where Do Meteorites Come From?
Most meteorites originate from the asteroid belt between Mars and Jupiter. These fragments are the remains of ancient protoplanets that collided and broke apart billions of years ago. As these celestial bodies cooled and crystallised, they formed distinct types of meteorites that fall into three primary categories:
Stony Meteorites
Stony meteorites are the most common type, accounting for about 95% of all known falls. They come from the crust and mantle of asteroids and are subdivided into:
Chondrites: These contain chondrules, tiny spherical mineral grains formed over 4.5 billion years ago. Rich in organic compounds and water-bearing minerals, chondrites preserve some of the solar system's oldest material.
Achondrites: These lack chondrules and come from parent bodies that underwent melting and geological differentiation. Structurally similar to Earth’s igneous rocks, achondrites are rarer and may originate from the Moon or Mars.
Iron Meteorites
Iron meteorites are believed to come from the metallic cores of differentiated asteroids that were shattered in cosmic collisions. Composed primarily of iron and nickel, these meteorites often display distinctive crystalline patterns known as the Widmanstätten structure, a unique feature revealed when the surface is cut and etched.
Stony-Iron Meteorites
Stony-iron meteorites are the rarest category, making up less than 0.2% of all finds. These specimens consist of approximately equal parts metal and silicate minerals. The most famous type, pallasites, contain vibrant olivine (peridot) crystals suspended in a metal matrix. They are believed to form at the boundary between a planetesimal's metal core and silicate mantle.
