 Ceres is possibly a surviving protoplanet ( planetary embryo ) , which formed 4 @.@ 57 billion years ago in the asteroid belt . Although the majority of inner Solar System protoplanets ( including all lunar- to Mars @-@ sized bodies ) either merged with other protoplanets to form terrestrial planets or were ejected from the Solar System by Jupiter , Ceres is thought to have survived relatively intact . An alternative theory proposes that Ceres formed in the Kuiper belt and later migrated to the asteroid belt . The discovery of ammonia salts in Occator crater supports an origin in the outer Solar System . Another possible protoplanet , Vesta , is less than half the size of Ceres ; it suffered a major impact after solidifying , losing ~ 1 % of its mass . 
 Ceres <a href='drop_aux' title='1'><mark>is</mark></a>possibly a surviving protoplanet ( planetary embryo ) , which<a href='been_done' title='2'><mark></mark></a> formed 4 @.@ 57 billion years ago in the asteroid belt . Although the majority of inner Solar System protoplanets ( including all lunar- to Mars @-@ sized bodies ) either merged with other protoplanets to form terrestrial planets or <a href='uninflect' title='3'><mark>were</mark></a> ejected from the Solar System by Jupiter , Ceres is thought to <a href='been_done' title='4'><mark>have</mark></a> survived relatively intact . An alternative theory <a href='uninflect' title='5'><mark>proposes</mark></a> that Ceres formed in the Kuiper belt and later migrated to the asteroid belt . The discovery of ammonia salts in Occator crater <a href='uninflect' title='6'><mark>supports</mark></a> an origin in the outer Solar System . Another possible protoplanet , Vesta , is less than half the size of Ceres ; it<a href='been_done' title='7'><mark></mark></a> suffered a major impact after solidifying , losing ~ 1 % of its mass . 
Ceres possibly a surviving protoplanet ( planetary embryo ) , which done formed 4 @.@ 57 billion yrs ago in the asteroid belt . Although the majority of inner Solar System protoplanets ( including alll lunar- to Mars @-@ sized bodies ) either merged w/ other protoplanets to form terrestrial planets or was ejected from da Solar System by Jupiter , Ceres is thought to done survived relatively intact . An alternative theory propose dat Ceres formed in the Kuiper belt and later migrated to tdaasteroid belt . The discovery of ammonia salts in Occator crater support an origin in the outer Solar System . Another possible protoplanet , Vesta , is less den half the size of Ceres ; it done suffered a major impact after solidifying , losing ~ 1 % of its mass .