 The images returned from Galileo , and the subsequent measurement of Ida 's mass , provided new insights into the geology of S @-@ type asteroids . Before the Galileo flyby , many different theories had been proposed to explain their mineral composition . Determining their composition permits a correlation between meteorites falling to the Earth and their origin in the asteroid belt . Data returned from the flyby pointed to S @-@ type asteroids as the source for the ordinary chondrite meteorites , the most common type found on the Earth 's surface . 
