Why is the preservation of original material in asteroids compelling for study?

They never accumulated enough mass for major chemical differentiation like Earth.

Asteroids are profoundly important to scientists because they are archives of the very earliest moments of the Solar System’s birth, approximately 4.6 billion years ago. When the Sun ignited and the protoplanetary disk began forming planets, smaller bodies like asteroids failed to gather enough mass to initiate major chemical differentiation processes, unlike larger bodies such as Earth or Mars, which separated into distinct crustal, mantle, and core layers. This lack of internal processing means that asteroids retain the pristine, original material from which the entire planetary neighborhood formed. This preservation is the primary justification for extensive study, as it allows researchers to chemically reconstruct the initial makeup of the solar nebula that gave rise to everything else.