The relative abundances of elements contained within chondritic meteorites (see chondrite), and in particular within C1 carbonaceous chondrites, are believed to provide the best estimate of the composition of the primitive material in the solar system from which the planets formed. Comparison of C1 carbonaceous chondrites with the solar abundances of elements (obtained by spectroscopic studies) show that, for non-volatile elements, the abundances are almost identical. On the other hand, the composition of ordinary chondrites is believed to be similar to the bulk composition of the Earth.