What is the main component found in meteorites that is significant for understanding Earth's origin?

The main component found in meteorites that is significant for understanding Earth's origin is iridium. This element is part of a group known as "noble metals" and is rare on Earth’s crust but more abundant in certain types of meteorites, particularly those from asteroids. The presence of iridium in geological layers, especially in the boundary associated with the extinction of the dinosaurs, provides evidence for the impact hypothesis, suggesting that a meteorite struck the Earth and caused significant environmental changes.

Studying meteorites, which are remnants from the early solar system, gives scientists insights into the building blocks of planets, as meteorites can contain materials and isotopes that help reconstruct the conditions of the early solar nebula from which Earth and other planets formed. This makes iridium a critical element in the study of planetary formation and the geological history of Earth.