The origin of meteorites

Current hypotheses generally interpret chondritic meteorites as being debris from a disrupted planet. It is suggested that these meteorites are not fragments of such a body, but have always been independent and individual objects. They can have been produced by the recrystallization of material now represented by the carbonaceous chondrites. The composition of carbonaceous chondrites is such that if they are heated above 600°C they would give a mixture of olivine, orthopyroxene, and nickel-iron similar to that of the chondritic meteorites. The friable and porous nature and the chondritic structure of these objects suggest recrystallization essentially in the solid state, as does the intimate admixture of nickel-iron and silicate. The other types of meteorites—achondrites, pallasites, and siderites—can be explained as fragments of a differentiated planetoid or planetoids formed by the aggregation of chondrites.